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33.6 Diseases of skin apendages

Posted by Dr.Md.Hadiuzzaman on February 12, 2013 at 12:40 AM Comments comments (0)

Hirsutism

Clinical features

Hirsutism is an excess of terminal hair growth in women in a pattern more typical of men.

Androgen-dependent growth areas affected include the upper lip, cheeks , chin, central chest, breasts, lower abdomen, and groin.

Associated with other signs of virilization, which include

                                             Temporal balding,

                                             masculine habitus,

                                            deepening of the voice,

                                            clitoral hypertrophy,

                                            and amenorrhea.

Acne is an additional sign of hyperandrogenism.


Pathogenesis

When virilization accompanies hirsutism, especially when progression is rapid, a neoplastic cause is likely.

In the absence of virilization, a neoplastic cause is extremely unlikely.

Most medically significant hirsutism is related to the polycystic ovarian syndrome (PCOS, hyperinsulinemic hyperandrogenism with anovulation).

In a study of 873 patients with medically significant hirsutism, PCOS was present in 82%.

Idiopathic hirsutism was present in 4.7%, and 6.75% of the patients had elevated androgen levels and hirsutism with normal ovulation.

Ethnic variation should be considered when evaluating hirsutism. Women of Southwest Asian, Eastern European and southern European heritage commonly have facial, abdominal, and thigh hair; whereas Asian and Indian women generally have little terminal hair growth in these areas.

In women, androgen biosynthesis occurs in the adrenal and ovary. Testosterone and the androgen precursor androstenedione are secreted by the ovary. The adrenal contributions are preandrogens: dehydroepiandrosterone (DHEA), DHEA sulfate, and androstenedione. They require peripheral conversion in the skin and liver to testosterone.

Testosterone is converted to dihydrotestosterone, the androgen that promotes androgen-dependent hair growth, in the hair follicle by 5-α-reductase. Receptor molecules in the end organ are necessary for binding and hormone action at that level. Because testosterone is normally bound to carrier molecules in the plasma at a 99% level, and it is the unbound testosterone that is active, the levels of free testosterone correlate with clinical evidence of androgen excess.

Hirsutism may result from excessive secretion of androgens from either the ovary or the adrenal gland. The excessive secretion may be from functional excesses or, rarely, from neoplastic processes. Ovarian causes include PCOS (Stein–Leventhal syndrome), and a variety of ovarian tumors, both benign and malignant. PCOS is defined by anovulation (fewer than nine periods a year or periods longer than 40 days apart) with clinical evidence of hyperandrogenism. Ovarian cysts are not required for the diagnosis, and laboratory and imaging studies are not required to establish the diagnosis.

The pathogenesis of PCOS may relate to insulin resistance with resultant elevated insulin levels leading to ovarian overproduction of androgens. Prevalence rates of PCOS for black and white women in the US are 8.0% and 4.8%, respectively.

Ovarian tumors include unilateral benign microadenomas, arrhenoblastomas. Leydig cell tumors, hilar cell tumors, granular/theca cell tumors, and luteomas are rare causes of hirsutism. In tumor-associated hirsutism, the onset is usually rapid, occurs with other signs of virilization, and begins between the ages of 20 and 40.

Adrenal causes include congenital adrenal hyperplasia (CAH) and adrenal tumors, such as adrenal adenomas and carcinomas. The adrenogenital syndrome or CAH is an autosomal-dominant disorder that may result from deficiencies of the following enzymes: 21-hydroxylase (most common form), 11β-hydroxylase, or 3β-hydroxy steroid dehydrogenase. Onset is generally in childhood, with ambiguous genitalia, precocious growth, and virilism. Nonclassic (adult-onset) CAH may present with hirsutism.

Pituitary causes include Cushing's disease, acromegaly, and prolactin-secreting adenomas. Prolactin-secreting microadenomas have a 20% incidence of hirsutism and acne. Prolactin elevations may be seen in patients with PCOS. Other conditions in which prolactin levels may be elevated and that may lead to hirsutism include hypothyroidism, phenothiazine intake, and hepatorenal failure.

Other causes of hirsutism include the exogenous intake of androgens. End-organ hypersensitivity may be a mechanism in patients with a normal evaluation. Drugs such as minoxidil, diazoxide, corticosteroids, and phenytoin, which have been reported to cause hirsutism, generally cause hypertrichosis—a generalized increase in hair that is not limited to the androgen-sensitive areas.

Evaluation

Most hirsutism is related to ethnic heritage or PCOS. 21-Hydroxylase-deficient nonclassic adrenal hyperplasia, the hyperandrogenic insulin-resistant acanthosis nigricans syndromes, and androgen-secreting tumors are relatively uncommon causes. A careful history and physical examination are essential. The history should focus on onset and progression, virilization, menstrual and pregnancy history, and family/racial background. Physical examination may reveal signs of Cushing's disease, hypothyroidism, or acromegaly. Other signs to be evaluated are the distribution of muscle mass and body fat, clitoral dimensions, voice depth, and galactorrhea.

Laboratory evaluation is controversial. In the authors’ opinion, testing is of value only when it affects management. If this is accepted, there is no mandatory hormonal testing for stable hirsutism in patients who have no signs of virilization. A diagnosis of PCOS does not require laboratory confirmation. Determination of serum lipids and testing for glucose intolerance may be the most important laboratory evaluations in patients with PCOS, as they have the greatest impact on management and long-term prognosis. When the history and physical examination suggest the possibility of a neoplasm, laboratory evaluation should include a total testosterone level. A dehydroepiandrosterone sulfate level is commonly performed if an adrenal cause is suspected. A 24 h urine cortisol test is the gold standard for the diagnosis of Cushing's disease. Measurement of thyroid-stimulating hormone (TSH), growth hormone, and somatomedin C levels are indicated if the history and physical examination suggest hypothyroidism or acromegaly.

Dexamethasone suppression tests are recommended by some authorities, but the results often do not affect management. A baseline 17-hydroxyprogesterone and adrenocorticotropic hormone (ACTH) stimulation test can screen for late-onset CAH, but steroid replacement has not been proved to result in better outcomes than empiric treatment with antiandrogens. Baseline 17-hydroxyprogesterone may be normal in some women with nonclassic 21-hydroxylase deficiency, and ACTH stimulation may result in overdiagnosis of the syndrome. An exaggerated 17-hydroxyprogesterone response to ACTH stimulation is common in PCOS at a pharmacologic dose (250 µg) but not at a physiologic dose (1 µg) of ACTH. An ovarian origin of hirsutism can be identified by a buserelin test in 30% of patients with hirsutism and by dexamethasone in 22% of patients, but data proving that buserelin challenge results in better outcomes are lacking. A prolactin level will screen for prolactin-secreting tumors, but will also lead to further expensive testing in many patients ultimately diagnosed with PCOS. A prolactin level should be obtained in any patient with galactorrhea, but is of limited value as a routine screening test for patients with hirsutism alone.

If signs of acromegaly, Cushing's disease, or virilization are present clinically, referral to an endocrinologist is recommended. The presence of major menstrual irregularities is also an indication for referral to an endocrinologist or gynecologist. Although 90% of women with hirsutism have an elevated testosterone level, elevations above 200 ng/dL and rapid onset or progressive virilization suggest serious underlying disease. A major elevation in the DHEA sulfate level (greater than 7000 ng/mL) suggests an adrenal neoplasm, and imaging of the adrenal gland is recommended. Many patients with late-onset CAH will have normal screening DHEA sulfate. Patients with prolactin levels above 20 ng/mL should likewise be referred for further evaluation with an MRI or CT scan. Polymorphisms in the gene coding for sex hormone-binding globulin have been identified in some families with hirsutism, but such testing does not affect management.

Treatment

Various forms of mechanical, chemical, and laser epilation can be performed, as for hypertrichosis

Spironolactone with various oral contraceptives, cyproterone acetate plus ethinyl estradiol, gonadotropin-releasing hormone agonists such as leuprolide and nafarelin, flutamide, finasteride, and topical eflornithine have been used successfully alone and in various combinations to treat hirsutism.

The optimal combination and dosage remain to be determined. Finasteride at doses of 2.5–5 mg/day has been shown to decrease hair number and diameter in women with hirsutism. The combination of spironolactone, 100 mg/day, plus finasteride, 5 mg/day, has been shown to be superior to spironolactone, 100 mg/day, alone. An analysis of the current literature suggested that spironolactone alone, 100 mg/day, is superior to finasteride alone, 5 mg/day, and low-dose cyproterone acetate alone, 12.5 mg/day for the first 10 days of a cycle, in the treatment of hirsutism. As spironolactone is commonly used at a dose of 100 mg twice a day, further studies are needed comparing this higher dose with other modes of therapy. In a prospective, randomized study of Diane 35 (cyproterone acetate [CPA], 2 mg, and ethinyl estradiol, 35 µg), Diane 35 plus spironolactone, and spironolactone alone, all treatments were well tolerated. Combination therapy resulted in superior measured endocrine responses, but the authors concluded that spironolactone alone was the most cost-effective treatment. The choice of an oral contraceptive (OC) is also controversial. Third-generation OCs result in a significant increase in sex hormone-binding globulin and decrease in free testosterone, but both second- and third-generation OCs are clinically effective in treating hirsutism. When flutamide is used, initial treatment with 250 mg/day is followed by a long maintenance treatment period using 125 mg/day.

Insulin sensitizers are being studied in the treatment of hirsutism, particularly PCOS. The best data to date are for metformin. Metformin therapy has been shown to control menstrual cycles and improve fertility in women with PCOS. It causes a decline in testosterone and insulin levels. Oligomenorrheic women with an increased luteinizing hormone (LH) to follicle-stimulating hormone (FSH) ratio and lower testosterone levels respond best. Spironolactone, 50 mg/day, was superior to metformin, 1000 mg/day, in the treatment of hirsutism and menstrual cycle frequency in a study of 82 adolescent and young women with PCOS. Doses of 200 mg/day are commonly used to treat hirsutism. At this dose, menstrual irregularities induced by the drug are common, and it may be best used in combination with an OC pill. Yasmin, which contains the progestogen drospirenone, has been shown to provide good cycle control for women with PCOS, with an improvement in acne but not in other symptoms of the syndrome. Good correlation has been noted between an increase in ovulation frequency with clomiphene citrate and the chance of pregnancy in women with PCOS. Other options include acarbose, gonadotrophins, and laparoscopic ovarian drilling. Infertility is best managed by a specialist in this field. Empiric treatment with an antiandrogen may be as good as steroid replacement for the management of hirsutism in patients with nonclassic CAH.


Trichomycosis axillaris

Discrete nodules, 1–2 mm in size and attached firmly to the hair shafts of the axillary or pubic areas, characterize trichomycosis.

The color of the nodules may be yellow, red, or black.

Hyperhidrosis of the affected regions is usually present.

A yellowish discoloration of the axillae is sometimes noted.

Large numbers of Corynebacterium are present in the concretions.

The disorder may coexist with erythrasma and pitted keratolysis.

Treatment with topical antibiotic preparations, such as topical clindamycin or erythromycin, or naftifine, which has antibacterial properties, combined with any modality that will decrease the hyperhidrosis, is effective, but shaving is faster.

 


 

33.5 Diseases of skin apendages

Posted by Dr.Md.Hadiuzzaman on February 12, 2013 at 12:35 AM Comments comments (0)

Pseudofolliculitis barbae

Pseudofolliculitis barbae are hairs that, after appearing at the surface, curve back and pierce the skin as ingrowing hairs. This results in inflammatory papules and pustules, which may scar . In severe cases, large deforming keloids may result in the beard area.

Pseudofolliculitis of the beard is seen in more than 50% of black men, who must sometimes give up shaving to alleviate the disorder. White persons are uncommonly affected; however, it is more common in renal transplant recipients. Tenderness responds to mid-strength topical steroids. The use of clippers or chemical depilatories, glycolic acid lotion, and adjunctive antibiotic therapy may be helpful.

Benzoyl peroxide 5%

clindamycin 1% gel has been shown to be effective in double-blind evaluation.

Laser hair removal with the long-pulse Nd:YAG laser is suitable for a wide range of skin types. The diode laser has also been used.


Pili multigemini

This rare malformation is characterized by the presence of bifurcated or multiple divided hair matrices and papillae, giving rise to the formation of multiple hair shafts within the individual follicles. It sometimes follows lines of Blaschko. Mehregan et al reported a patient with cleidocranial dysostosis and extensive pili multigemini over the heavily bearded chin and cheek areas.

There is no treatment.

 Pili bifurcatiIn this disorder, bifurcation is found in short segments along the shafts of several hairs. Each branch of the bifurcation is covered with its own cuticle. It has been seen in association with the trisomy 8 mosaic syndrome. Pili bifurcati differs from pili multigemini in which a single follicular matrix produces two different-sized hair shafts with separate cuticles that do not fuse again. Trichoptilosis is characterized by split distal ends that are never surrounded by a complete cuticle.

Trichostasis spinulosa

Trichostasis spinulosa is a common disorder of the hair follicles that clinically gives the impression of blackheads, but the follicles are filled with funnel-shaped, horny plugs within which are bundles of vellus hairs (Fig. 33-30). The hairs are round at their proximal ends and shredded distally. The disease occurs primarily on the nose and forehead, but may also occur on the trunk and be accompanied by pruritus. Dermoscopy or microscopy can be used to establish the diagnosis. The condition may be more common in patients in renal failure.

Trichostasis spinulosa results from retention of telogen hairs, which are derived from a single hair matrix. It is primarily caused by a hyperkeratosis of the follicular infundibulum, which leads to a partial obstruction of the follicular orifice and thus does not permit shedding of small telogen hairs.

The plugs may be removed with hydroactive adhesive (Biore) pads. Keratolytics are also effective after using a wax depilatory. The pulsed diode laser has been used successfully, and application of 0.05% tretinoin solution, applied daily for 2 or 3 months, may also produce satisfactory results.

 


Intermittent hair-follicle dystrophy

Birnbaum et al reported a disorder of the hair follicle leading to increased fragility of the shaft, with no identifiable biochemical disturbance. The prevalence of this disorder is unknown.

Bubble hair deformity

Bubble hairs appear as areas of hair with altered texture. Fragility has been reported. The hairs may be curved or straight and stiff. Small, bubble-like defects are found within the hair shafts on light and electron microscopy. The condition is produced by overheating of wet hair with a malfunctioning hair dryer, analogous to the popping of popcorn. All damp hair will develop bubbles of gas when exposed to high heat.

 

Hypertrichosis

Hypertrichosis is an overgrowth of hair not localized to the androgen-dependent areas of the skin.

Several forms exist. Many cases are induced by medications, including minoxidil, cyclosporine, and efalizumab. The excessive hair growth can be managed with bleaching, trimming, shaving, plucking, waxing, chemical depilatories, and electrosurgical epilation. Laser treatment with long-pulse Nd:YAG, diode, ruby, long- and short-pulse alexandrite lasers, and intense pulsed light sources can be effective. Skin type must be considered when choosing a laser system. The greatest experience in dark skin types has been with the long-pulse Nd:YAG laser.

Localized acquired hypertrichosis

Eyelash trichomegaly can occur with erlotinib, latanoprost, and intentionally with bimatoprost. Dermal tumors, such as melanocytic nevi, smooth muscle hamartomas, meningiomas, or Becker nevi, may have excessive terminal hair growth. Repeated irritation, trauma, occlusion under a cast, eczematous states, topical steroid use, linear melorheostotic scleroderma, lymphedema associated with filariasis, the Crow–Fukase (POEMS) syndrome, and pretibial myxedema may be other situations in which there is a localized increase in hair growth. Porphyrias generally show a localized hypertrichosis over the malar area, such as in porphyria cutanea tarda or variegate porphyria; however, in the Gunther variety of erythropoietic porphyria it may be generalized or more diffuse in nature.

Localized congenital hypertrichosis

Hypertrichosis cubiti (hairy elbows) consists of long vellus hair on the extensor surfaces of the distal third of the upper arm and the proximal third of the forearm bilaterally. It is a progressive, excessive growth of lanugo hairs that often begins in infancy; the hairs may reach a length of 10 cm.

Later they become coarser, but regression has been observed during adolescence. There appear to be familial cases and a sporadic form. Short stature and some developmental abnormalities are present in some cases; however, there is no need for endocrine studies or other evaluation. The condition appears to be of cosmetic significance only.

Other causes of localized congenital hypertrichosis include congenital nevocytic nevi, anterior cervical hypertrichosis, and simple nevoid hypertrichosis. Localized hypertrichosis may be a sign of underlying spinal dysraphism when it occurs over the sacral midline.

Generalized congenital hypertrichosis (congenital hypertrichosis lanuginosa)

This rare type of excessive and generalized hairiness is a fully penetrant X-linked dominant trait. The entire body is covered with fine vellus hairs 2–10 cm long . The scalp hair appears to be normal. Except for the palms and soles, all other areas are covered. Congenital hypertrichosis lanuginosa may be associated with dental anomalies and gingival fibromatosis. This type of hairiness has attracted considerable attention over the centuries. Hair removal by laser may be quite useful.

 Other cases of congenital generalized hypertrichosis may be secondary to drug ingestion by the mother. The fetal hydantoin syndrome is characterized by hypertrichosis, depressed nasal bridge, large lips, a wide mouth, and a short, webbed neck. The fetal alcohol syndrome includes hypertrichosis, a small face, capillary hemangiomas, and physical and mental retardation. A case of generalized hypertrichosis and multiple congenital defects was reported by Kaler et al in a baby born to a mother who used minoxidil throughout pregnancy. Fetal valproate syndrome is characterized by generalized hypertrichosis sparing the palms and soles, coarse facies, gum hypertrophy, hypotonia, club feet and club hands, and abnormal dermatoglyphics.

 Generalized or patterned acquired hypertrichosis

These cases include those caused by acquired hypertrichosis lanuginosa, those associated with various syndromes, and those secondary to drug intake. Acquired hypertrichosis lanuginosa (Fig. 33-32) is an ominous sign of internal malignancy. Syndromes associated with increased hair growth include lipoatrophic diabetes, stiff skin syndrome, Down syndrome, Rubenstein–Taybi syndrome, Laband syndrome, Cornelia de Lange syndrome, Hurler syndrome, leprechaunism, Winchester syndrome, the Schynzel–Giedier syndrome, and hypertrichosis with acromegalic features.

Drugs associated with hypertrichosis include minoxidil, cyclosporine, diphenylhydantoin, diazoxide, streptomycin, penicillamine, corticosteroids, danazol, psoralens, hexachlorobenzene, PUVA, topical bimatoprost, topical steroids, and topical androgens.

 



 

33.4 Diseases of skin apendages

Posted by Dr.Md.Hadiuzzaman on February 12, 2013 at 12:35 AM Comments comments (0)

Hair color

Melanin in the hair follicles is produced in the cytoplasm of the melanocytes. Organelles involved include the endoplasmic reticulum, ribosomes, and Golgi apparatus.

Melanocytes producing hair pigment are associated with the hair matrix, and melanogenesis occurs only during anagen.

This cyclic melanin synthesis distinguishes follicular melanogenesis from the continuous melanogenesis of the epidermis. With age, cyclic melanocytic activity in the follicular unit declines. By 40 years of age most individuals show evidence of graying. Graying results primarily from a reduction in tyrosinase activity within hair bulb melanocytes. Defective migration of melanocytes from a diminishing reservoir in the outer root sheath may play a role. Physiologic graying may also be related to reactive oxygen species-mediated damage to nuclear and mitochondrial DNA in bulbar melanocytes. The melanocortin 1 receptor gene (MCR1) is closely related to red hair, freckling, and sun sensitivity.

The pigment in black and dark brown hair is composed of eumelanin, whereas in blond and red hair it is pheomelanin. In black hair the melanocytes contain the densest melanosomes. Brown hair differs only by its smaller melanosomes. Light brown hair consists of a mixture of the melanosomes of dark hair and the incomplete melanosomes of blond hair. Many of the melanosomes in blond hair develop only on the matrix fibers and not in the spaces between the fibers.

Red hair shows incomplete melanin deposits on the matrix fibers to produce a blotchy-appearing melanosome. Pheomelanin is distinguished by its relatively high content of sulfur, which results from the addition of cysteine to dopaquinone along the biosynthetic pathway of melanin synthesis.

In gray hair (canities), melanogenic activity is decreased as a result of fewer melanocytes and melanosomes, as well as a gradual loss of tyrosinase activity. Graying of the scalp hair is genetically determined and may start at any age. Usually, it begins at the temples and progresses with time. The beard usually follows, with the body hair graying last. Premature whitening of scalp hair is usually caused by vitiligo, sometimes without recognized, or actually without, lesions of glabrous skin.

Early graying (before age 20 in white or before age 30 in black persons) is usually familial; however, it may occur in progeria, Rothmund–Thomson syndrome, Böök syndrome, and Werner syndrome.

In poliosis, gray or white hair occurs in circumscribed patches. This may occur in Waardenburg syndrome and piebaldism, Tietz syndrome, Alezzandrini syndrome, neurofibromatosis, and tuberous sclerosis. Poliosis is also found in association with regressing melanoma, vitiligo, and Vogt–Koyanagi syndrome, and may be seen in alopecia areata when the new hairs grow. Migratory poliosis without hair loss may represent a forme fruste of alopecia areata.

Green hair has been traced to copper in the water of a swimming pool. This occurs only in blond or light hair, and may be treated with topical EDTA, penicillamine-containing shampoos, or 1.5% aqueous 1-hydroxyethyl diphosphonic acid. Tars and chrysarobin stain light-colored hair brown.

Changes in hair color occur in various disorders. The hair is blond in phenylketonuria and homocystinuria. Light hair is also seen in oasthouse disease (familial methionine malabsorption), Menkes kinky hair syndrome, and albinism. In Griscelli and Chédiak–Higashi syndromes the hair has a silvery sheen. In kwashiorkor the hair assumes a red–blond color and may demonstrate periodic banding (flag sign, segmental heterochromia). Alternating light and dark bands may also occur in iron deficiency anemia and with courses of sunitinib. In vitamin B12 deficiency and with IFN therapy, whitening may occur. The disorder has been called canities segmentata sideropenica. It responds completely to iron supplementation. Triparanol is associated with hypopigmented hair. Minoxidil (by changing vellus to terminal hairs) causes darkening of hair; another hypotensive agent, diazoxide, gives the hair a reddish tint. Chloroquine therapy may cause hair whitening, usually in redheads and blonds, but not in brunettes. Pigmentation of the eyelashes and irides has been described with latanoprost. Xanthotrichia (yellow hair) has been noted with selenium sulfide and dihydroxyacetone.

Many black patients with acquired immunodeficiency syndrome (AIDS) have experienced softening, straightening, lightening, and thinning of their hair. Patients with human immunodeficiency virus (HIV)-1 infection may also experience elongated eyelashes and telogen effluvium.


Hair structure defects

Examination of hairs for structural defects is greatly facilitated by a method devised by Shelley: putting a piece of double-stick tape on a microscope slide and aligning 5 cm segments of hair in parallel on it. Dermoscopy can be useful in assessing hair morphology. Microscopic mounts of hairs are best examined under a dissecting microscope or polarized light. Gold-coating and scanning electron microscopy can also be done on hairs so mounted. Hairs from multiple body sites may need to be sampled. This has been documented in Netherton syndrome where scalp hair can be normal while eyebrow hair demonstrates the characteristic hair shaft defect.

 

Hair casts (pseudonits)

Hair casts represent remnants of the inner root sheath. They often occur in great numbers and may mimic nits in the scalp. While nits are firmly cemented to the hair shaft, hair casts slide freely along the shaft. Taeb et al reviewed 36 published cases and distinguished two groups: girls between 2 and 8 years of age with diffuse involvement and no scalp disease, and children and adults with psoriasis, lichen planus, seborrheic dermatitis, or trichotillomania. Keipert made a similar distinction, separating a large group of cases with some keratinizing disorder of the scalp and dark, oddly shaped masses of keratin adherent to or surrounding the hairs, which he called parakeratotic hair casts; and lighter-colored tubular casts, 2–4 mm long, which he called peripilar hair casts. Taeb et al found 0.025% tretinoin lotion effective. False hair casts may occur as a result of hair spray or deodorant concretions. Immunoglobulin casts and cutaneous spicules have been noted in multiple myeloma.

Pili torti

Also known as twisted hairs, pili torti is a malformation of hair characterized by twisting of the hair shaft on its own axis (Fig. 33-22). The hair shaft is segmentally thickened, and light and dark segments are seen. Scalp hair, eyebrows, and eyelashes may be affected. The hairs are brittle and easily broken.

In the classic type, unassociated with other disorders, onset is usually in early childhood; by puberty, it has usually improved. Clinically, it may be associated with patchy alopecia and short, broken hairs. It usually follows a dominant inheritance pattern, though recessive and sporadic cases have been reported. Acquired cases have been described in young women with anorexia nervosa. Pili torti may be seen with associated abnormalities. The Björnstad syndrome consists of congenital deafness of the cochlear type, with pili torti. Both autosomal-dominant and autosomal-recessive inheritance patterns have been described. BCS1L mutations cause the Björnstad syndrome. The gene encodes an ATPase necessary for the assembly of complex III in mitochondria. BCS1L mutations also cause lethal conditions, including the complex III deficiency and the GRACILE syndrome, with severe multisystem and neurologic manifestations.

Pili torti also may occur in citrullinemia (argininosuccinate synthetase deficiency), Menkes kinky hair syndrome, Bazex follicular atrophoderma syndrome, ectodermal dysplasias, Crandall syndrome (pili torti, nerve deafness, hypogonadism), Netherton syndrome (along with bamboo hair), with isotretinoin and etretinate therapy, in anorexia nervosa, and in trichothiodystrophy.

Laron syndrome is an autosomal-recessive disease with primary insulin-like growth factor 1 deficiency and primary growth hormone insensitivity. Affected children have sparse hair and frontal recession. Pili torti et canaliculi, tapered hair, and trichorrhexis nodosa have been noted.

 

Menkes kinky hair syndrome

Pili torti, and often monilethrix and trichorrhexis nodosa, are all common in the hairs in this sex-linked recessively inherited disorder. It has also been called steely hair disease, because the hair resembles steel wool. The characteristic ivory color of the hair appears between 1 and 5 months of age. Drowsiness, lethargy, convulsive seizures, severe neurologic deterioration, and periodic hypothermia ensue with death at an early age. Hairs become wiry, sparse, fragile, and twisted about their long axes. Osteoporosis, and dental and ocular abnormalities are common. The skin is pale and the face pudgy, and the upper lip has an exaggerated “Cupid's bow” configuration. The occipital horn syndrome, primarily a connective tissue disorder, is a milder variant of Menkes syndrome. Patients have a deficiency of serum copper and copper-dependent enzymes, resulting from mutations in the ATP7A gene. The gene encodes a trans-Golgi membrane-bound copper transporting P-type ATPase. Loss of this protein activity blocks the export of dietary copper from the gastrointestinal tract and causes the copper deficiency. Low serum copper and ceruloplasmin are characteristic, but are not seen in all patients. They are particularly variable in the first weeks of life. Other tests helpful for screening include the ratio of catechols, such as dihydroxyphenylalanine to dihydroxyphenylglycol. High levels of the catechols DOPA, dihydrophenylacetic acid, and dopamine, and low levels of dihydroxyphenylglycol are characteristic. Studies of copper egress in cultured fibroblasts have also been used. Early detection allows for genetic counseling and the institution of copper histidine treatment, which is being studied and has shown promising results in some infants. Pamidronate treatment is associated with an increase in bone mineral density in children with Menkes disease. In zebra fish, antisense morpholino oligonucleotides directed against the splice-site junctions of two mutant calamity alleles were able to correct the molecular defect. This is a promising area for research.

 

Uncombable hair syndrome

First reported in 1973 by Dupré et al as cheveux incoiffables (undressable hairs) and by Stroud and Mehergan as spun-glass hair, the microscopic abnormality of a triangular cross-sectional appearance with a longitudinal groove gives the disease its other name, pili triangulati et canaliculi.

Clinically, the defect is noted in the first few years of life as dry, blond, shiny hair that stands straight out from the scalp and cannot be combed (Fig. 33-23). On light microscopy it may appear quite normal when viewed lengthwise, but on horizontal sectioning and on scanning electron microscopy it shows the longitudinal grooves that make it abnormally rigid. These depressions are sometimes seen in unaffected persons, so that 50% of hairs need to be affected for the condition to be clinically detectable.

Autosomal-dominant, autosomal-recessive, and sporadic forms have been described. Uncombable hair has been associated with angel-shaped phalango-epiphyseal dysplasia. It has also been seen in combination with retinal dystrophy, juvenile cataract, and brachydactyly. It has also been reported in a patient who acquired the abnormality at age 39 after an episode of diffuse alopecia treated with spironolactone. Although there are usually no associated ectodermal defects, isolated cases have been reported in which uncombable hair is one component of several clustered findings. Until more experience is available in the literature, grouping of these cases into new syndromes is premature.

Some patients have responded clinically to biotin, 0.3 mg orally three times a day. Some cases improve spontaneously in late childhood.

 Monilethrix

Monilethrix, also known as beaded hairs, is a rare hereditary disease. It is characterized by dryness, fragility, and sparseness of the scalp hair (Fig. 33-24), with fusiform or spindle-shaped swellings of the hair shaft separated by narrow atrophic segments. The hair tends to break at the delicate internodes. There is an occasional rupture at the node and longitudinal fissuring of the shaft, which also involves the nodes.

The disease is often associated with keratosis pilaris of the extensor surfaces, temples, and back of the neck. Hair on regions other than the scalp may be affected. Leukonychia may occur. Inheritance of monilethrix is an autosomal-dominant trait. It has been described in association with Menkes syndrome. Mutations in desmoglein 4 are seen in monilethrix and in localized autosomal-recessive hypotrichosis, a disorder that shares clinical features with monilethrix but lacks the characteristic hair shaft changes. Several cases of monilethrix have been linked to the type II keratin gene cluster on chromosome 12q13. Causative heterozygous mutations of a highly conserved glutamic acid residue of the type II hair keratins hHb6 and hHb1 occur. Both hHb1 and hHb6 are largely coexpressed in cortical trichocytes of the hair shaft, confirming that monilethrix is a disease of the hair cortex. Improvement of the hair may occur during pregnancy, but after delivery the hair returns to its original state. Improvement may also occur with age and there may be seasonal improvement during the summer. Improvement with acitretin has been reported.


Trichorrhexis nodosa

The affected hair shafts fracture easily and may have small white nodes arranged at irregular intervals. These nodes are the sites of fraying of the hair cortex. The splitting into strands produces a microscopic appearance suggestive of a pair of brooms stuck together end to end by their bristles. The hairs soon break at these nodes (Fig. 33-25). The number of these nodes along one hair shaft varies from one to several, depending on its length. These fractured hairs are found mostly on the scalp, often in just a small area or areas, but other sites such as the pubic area, axillae, and chest may be involved.

 Several categories or types of trichorrhexis nodosa have been described. Proximal trichorrhexis nodosa involves the proximal shafts of the hairs of black patients who traumatize their hair with styling or chemicals. The involved hairs break a few centimeters from the skin surface, resulting in patches of short hair. It appears to occur in genetically predisposed patients. Distal trichorrhexis nodosa affects primarily Asians and white patients; it occurs several inches from the scalp, and is associated with trichoptilosis, or longitudinal splitting, known as split ends. Acquired localized trichorrhexis nodosa is a common type in which the defect occurs in a localized area, a few centimeters across. A number of diseases accompany this type of trichorrhexis nodosa in which pruritus is a prominent symptom; scratching and rubbing may be the cause. Among such diseases are circumscribed neurodermatitis, contact dermatitis, and atopic dermatitis.

The occurrence of trichorrhexis nodosa in some patients with argininosuccinicaciduria has suggested an etiologic connection. Trichorrhexis nodosa has been described in Menkes kinky hair syndrome, Netherton syndrome, hypothyroidism, ectodermal dysplasia, the syndrome of intractable infant diarrhea, and trichothiodystrophy. Trichoschisis, a clean transverse fracture across the hair shaft, is more commonly present in trichothiodystrophy. The curly hair that may result from isotretinoin therapy has been attributed to extensive trichorrhexis nodosa. Because trauma may induce this hair shaft abnormality, the specificity of this finding in the above conditions may simply be fortuitous.

Treatment is directed toward the avoidance of trauma to the hair.

Trichorrhexis invaginata

Also known as bamboo hair, trichorrhexis invaginata is caused by intussusception of the hair shaft at the zone where keratinization begins. The invagination is caused by softness of the cortex in the keratogenous zone. The softness may be caused by inadequate conversion of –SH to S–S proteins in the cortex. The patient with bamboo hair will have nodose ball-and-socket deformities, with the socket forming the proximal and the ball part forming the distal portion of the node along the hair shaft. This type of hair is associated with Netherton syndrome. Occasionally, only the proximal half of the abnormality is seen; this has been called golf tee hairs.

Trichorrhexis invaginata associated with congenital ichthyosiform erythroderma or ichthyosis linearis circumflexa constitutes Netherton syndrome. Atopic manifestations and high IgE levels are commonly present. The bamboo hairs may be present not only on the scalp but also on the eyebrows, eyelashes, and rarely in other hairy areas. Hair sparsity is noted all over the body. The bamboo hairs may become normal within a few years. Other reported findings include pili torti, trichorrhexis nodosa, moniliform hairs, urticaria, angioedema, growth retardation, recurrent infections, multiple epithelial neoplasms, and mental retardation. An autosomal-recessive mode of inheritance has been suggested, although reported cases involving women far outnumber men. Pathogenic mutations have been identified in serine protease inhibitor Kazal-type 5 (SPINK5) on chromosome 5q32, a gene encoding lymphoepithelial Kazal-type-related inhibitor (LEKTI), a serine protease inhibitor involved in skin barrier formation and immunity. PUVA has been reported to help the circumflex linear ichthyosis, while etretinate has been reported both to exacerbate and to improve skin findings.

Menne et al reported the bamboo hair defect in very thin, probably vellus, hairs in a 7-year-old boy with short, thin, brittle scalp hairs and no eyebrows. They termed this a canestick deformity.

Pili annulati (ringed hair, spangled hair)

Pili annulati is an unusual disease in which the hair seems banded by alternating segments of light and dark color when seen in reflected light. The light bands are caused by clusters of abnormal air-filled cavities, which scatter light, and reduplicated lamina densa in the region of the root bulb.

Hair growth is normal in patients with pili annulati, although it is rarely associated with trichorrhexis nodosa-like breaks of the hair shaft. There are no other associated abnormalities of skin or other organ systems. It is inherited by autosomal-dominant mode, begins in infancy, and requires no treatment, since the spangled appearance of the hair is not unattractive (Fig. 33-26). The condition has been reported to disappear following recovery from alopecia totalis.

 Pili pseudoannulati

This anomaly of human hair mimics pili annulati. The two differ in that the light bands in pili annulati are caused by internal effects, whereas the bright segments in pili pseudoannulati are caused by reflection and refraction of light by flattened, twisted surfaces of hair. This latter type is a variant of normal hair.

Kinking hair

Acquired progressive kinking of the hair, first described and named by Wise and Sulzberger in 1932, involves a structural abnormality of kinking and twisting of the hair shaft at irregular intervals. The main recognized variant of this disorder begins in men in their late teens or early twenties on the frontotemporal or vertex regions, and then progresses to both the parietal and frontal areas. Usually straight, light brown hair becomes curly, frizzy, and lusterless.

When this occurs in the androgen-dependent areas of young men it is a precursor of male-pattern hair loss; usually these men have a strong family history of androgenetic alopecia. Treatment with topical minoxidil has not prevented development of hair thinning. “Whisker” hairs, the short dark hairs that grow anterior to the ears in young people who eventually develop androgenic alopecia, is felt to be a variant of acquired kinking of the hair.

Acquired hair kinking has been described in other clinical situations. Some reports detail prepubertal patients or women, as well as men, in whom kinking develops in non-androgen-dependent areas. In these reports alopecia has not developed, and the curly, frizzy hair may remain present or revert to its previous condition.

Widespread kinking of the hair may be induced by drugs, notably retinoids, and it may also occur in patients with AIDS.

Woolly hair

Woolly hair is present at birth and is usually most severe during childhood, when it is often impossible to brush the hair. In adult life there is a variable amelioration in the condition. There is a clear distinction between the appearance of the affected and nonaffected members of a family. Both autosomal-dominant and autosomal-recessive inheritance have been described. Woolly hair nevus has partial scalp involvement by woolly hair, which has a markedly reduced diameter. Naxos’ disease is an autosomal-recessive syndrome with arrhythmogenic right ventricular cardiomyopathy, diffuse nonepidermolytic palmoplantar keratoderma, and woolly hair. Hair abnormalities are a reliable marker for subsequent heart disease. The disease is caused by a mutation in the gene encoding plakoglobin. Carvajal syndrome is a familial cardiocutaneous syndrome consisting of woolly hair, palmoplantar keratoderma, and heart disease. It is caused by a recessive deletion mutation in desmoplakin.

Woolly hairs tend to unite into tight locks, whereas the hairs of black persons remain individual. The hair may not grow beyond a length of 12 cm, but may attain a normal appearance in adult life. In the familial group the eyebrows and hairs on the arms, legs, and pubic and axillary regions may be short and pale. There are no associated cutaneous or systemic diseases. A Dutch kindred has been described with premature loss of curly, brittle hair, premature loss of carious teeth, nail dystrophy, and acral keratoderma. It has been designated the curly hair-acral keratoderma-caries syndrome.

The microscopic findings of woolly hair include a decreased diameter, an ovoid shape on cross-section, a pili torti-like twisting about a longitudinal axis, trichorrhexis nodosa, and pili annulati.

Plica neuropathica (felted hair)

This is a curling, looping, intertwisting, and felting or matting of the hair in localized areas of the scalp. Predisposing factors include kinky hairs, changes in hair care, and a neurotic mental state. Plica polonica is an older name for this condition.

 



 


 

33.3 Diseases of skin apendages

Posted by Dr.Md.Hadiuzzaman on February 12, 2013 at 12:35 AM Comments comments (0)

Cicatricial alopecia

Cicatricial alopecia appears as areas of hair loss with absence of follicular ostia (Fig. 33-9). Acute lesions may appear as erythematous perifollicular papules, keratotic follicular spines, or pustules. Deep inflammatory lesions may be boggy or may resemble noncicatricial areata clinically. The inflammatory nature of the lesion may only be evident on biopsy.

Discoid lupus erythematosus, lichen planopilaris, sarcoidosis, and folliculitis decalvans are the most common inflammatory causes of cicatricial alopecia.Chronic bacterial and fungal infections plaques,   may produce inflammatory alopecia that mimics primary scarring alopecia. For example, fungal folliculitis may mimic lupus erythematosus.

Biopsy can confirm the diagnosis and provide prognostic information regarding the potential for new growth. A 4 mm punch biopsy will provide the pathologist with an adequate specimen. Smaller specimens are of limited value. The punch should be placed parallel to the direction of hair growth to avoid transecting follicles, and the punch should be advanced to the deep subcutaneous fat. The biopsy site will typically bleed profusely, but a 4 mm-wide strip of gel foam advanced into the defect will generally provide rapid hemostasis. Sutures are rarely necessary, and as the scar from a sutured biopsy site generally stretches back to the original dimensions of the biopsy, suturing provides little benefit to the patient.

Where to biopsy, how many biopsies to obtain, and how to process the tissue depend on the suspected diagnosis and the preference of the pathologist. In all cases, a pathologist experienced in the interpretation of scalp biopsies is an advantage. The pathologist may prefer vertical or transverse (horizontal) sectioning of the specimen. Each has advantages. Every follicular unit in the specimen will be demonstrated in transverse sections. Vertical sections are superior for demonstrating changes in the surface epidermis, dermoepidermal junction, superficial dermis, and subcutaneous fat. In general, the features of androgenetic (pattern) alopecia, telogen effluvium, and trichotillomania are better demonstrated in transverse (horizontal) sections through the specimen. Alopecia areata and syphilitic alopecia are well demonstrated in transverse sections if serial step sections are obtained to demonstrate deeper planes of section or if the block is cut horizontally in a bread-loaf fashion prior to embedding. They are equally well demonstrated with serial vertical sections through the block. Lupus erythematosus and lichen planopilaris are more easily demonstrated in serial vertical sections.

The diagnostic yield can be enhanced by pairing vertical and transverse sections. If two biopsies are done, one specimen can be bisected vertically for direct immunofluorescence (DIF) and hematoxylin and eosin (H&E) processing. It is most easily split by laying it on its side and bisecting it with a 15 blade pushed cleanly through the specimen in a single downward motion. Sawing at the specimen will not produce a satisfactory result. One-half of the bisected specimen is placed in formalin, and the other half in immunofluorescent media. The second specimen can be bisected for transverse sections in the clinic or left for the laboratory to bisect after processing. If it is to be bisected in the clinic, it should be placed on its side. The 15 blade should be pushed downward through the specimen in a single motion at the level of the mid-dermis. All pieces for vertical and transverse sections may be placed in a single bottle to be embedded in a single cassette.

In many forms of cicatricial alopecia, a biopsy of an active inflammatory lesion will be most diagnostic. In lupus erythematosus, the biopsy must be from a lesion of several months’ duration in order to demonstrate hyperkeratosis, follicular plugging, basement membrane thickening (Fig. 33-10), and dermal mucin. Only biopsies from established lesions of lupus will demonstrate reliable immunofluorescence.

When biopsies of the most active area of alopecia have failed to yield a definite diagnosis, a biopsy from a scarred area may provide additional information. Scars show loss of elastic tissue with the Verhoeff–van Gieson stain. The pattern of elastic tissue loss is the “footprint” of the preceding inflammatory process (Figs 33-11 and 33-12). Lichen planopilaris and folliculitis decalvans both affect the infundibulum. Both result in wedge-shaped superficial dermal scars. Discoid lupus erythematosus results in scarring of both the follicular units and the intervening dermis. Morphea does not produce a scar, but rather hyalinization of collagen bundles with preservation of the elastic fibers. In idiopathic pseudopelade, the fibrous tract remnants are widened, but the elastic tissue sheath at the periphery of the fibrous tract is preserved.

Most patients with cicatricial alopecia experience gradual progression of the alopecia, and the prolonged course of the disease may lead to inappropriate therapeutic complacency. The progressive destruction of hairs will result in ever-expanding areas of permanent alopecia. Therefore, cicatricial alopecia must be treated aggressively and early to avoid permanent disfigurement. Surgical revision of the hairless plaque is an option for stable end-stage alopecia, but unless the underlying disease is controlled, surgery may only lead to a flare of the underlying disease with progression of hair loss. Therapy may be forestalled by the inability to establish a definite diagnosis. To help guide therapy for patients who defy diagnosis, work groups of the North American Hair Research Society have proposed a classification scheme based on the type and pattern of inflammation. Some forms of destructive alopecia are lymphocyte-mediated, while some are suppurative processes. The type of infiltrate and the portion of the pilosebaceous unit affected can be used to guide therapy. This classification system may also allow patients to enroll in clinical trials, even in the absence of a definite diagnosis.

 Lymphoid-mediated disorders

Lupus erythematosus

Chronic cutaneous lupus of the scalp (discoid lupus erythematosus [DLE]) is a common cause of cicatricial alopecia. In active disease, anagen hairs may be easily extracted from the involved area. Usually, erythema, atrophy, follicular plugging, and mottled hyperpigmentation and hypopigmentation are present. Patients with chronic cutaneous lupus of the scalp may or may not have accompanying SLE or skin lesions of DLE on other parts of the body. The external ear canal and concha should always be examined, as they are common sites for discoid lesions. Occasionally, alopecia occurs in a plaque of tumid lupus. Lupus panniculitis may occasionally result in alopecia in the absence of surface skin changes. SLE is often associated with discoid lesions of the scalp. Patients with SLE may also have short miniaturized “lupus hairs” on the anterior scalp.

Biopsy of early lesions of DLE is often nondiagnostic. Patchy lymphoid inflammation and perifollicular mucinous fibrosis may be the only histologic findings. Focal vacuolar interface dermatitis may or may not be noted. Active established lesions, present for several months, have a higher diagnostic yield. Active established lesions usually demonstrate hyperkeratosis, follicular plugging, vacuolar interface dermatitis, basement membrane zone thickening, pigment incontinence, and dermal mucin. Perivascular and periadnexal lymphoid infiltrates are patchy and involve the eccrine coil and fibrous tract remnants. Fibrous tract involvement creates dense vertical columns of lymphocytes. The underlying subcutaneous tissue may demonstrate nodular lymphoplasmacytic infiltrates and fibrin or hyaline rings around necrotic fat. Hypertrophic lesions of chronic cutaneous lupus erythematosus often demonstrate lichenoid dermatitis. DIF may be nonspecific, but active established lesions typically demonstrate a “full house” (continuous granular deposition of IgG, IgA, IgM, and C3) at the dermoepidermal junction. When present, this pattern is particularly helpful in distinguishing lichenoid hypertrophic lupus erythematosus from lichen planopilaris. Burnt-out lesions of DLE demonstrate loss of elastic fibers throughout the dermis, which differs from the focal peri-infundibular wedge-shaped scars of lichen planopilaris. In systemic lupus, there may be follicular atrophy associated with pronounced dermal mucinosis.

Chronic cutaneous lupus may respond to intralesional or potent topical corticosteroids, but systemic therapy is frequently required. Antimalarials, retinoids, dapsone, thalidomide, sulfasalazine, mycophenolate mofetil, and methotrexate have been used successfully. Topical tazarotene and topical calcineurin inhibitors are generally disappointing.

Lichen planopilaris

Lichen planopilaris presents with perifollicular erythema and progressive scarring. Small follicular papules may be noted, or the lesion may resemble the ivory white irregular patches of pseudopelade. In some patients, typical polygonal flat-topped papules are present on the wrists and ankles, and lacy white lesions are noted on the oral and genital mucosa. Widespread follicular papules may be present on the trunk or extremities. In most patients, however, only the scalp is involved. Frontal fibrosing alopecia appears to be a variant of lichen planopilaris. Most patients are older women with bandlike frontotemporal alopecia (Fig. 33-13). Graham Little–Piccardi–Lassueur syndrome includes cicatricial alopecia on the scalp, keratosis pilaris in the skin of the trunk and extremities, and noncicatricial hair loss in the pubis and axillae. It has been described in association with complete androgen insensitivity syndrome, a condition that also presents with noncicatricial alopecia in the axillary and pubic hair.

 Diagnostic biopsies demonstrate lichenoid interface dermatitis of the follicular unit and sometimes the intervening epidermis. The entire fibrous tract may be filled with cytoid bodies (Fig. 33-14). The changes commonly occur focally and may be best visualized with serial vertical sections. Perifollicular mucinous fibrosis is common and focal perifollicular lymphoid infiltrates tend to involve the infundibulum (the infiltrates of lupus erythematosus tend to involve the isthmus). DIF may be negative or may reveal cytoid bodies and shaggy linear fibrin at the dermoepidermal junction.


Lichen planopilaris responds to oral and intralesional corticosteroids. Topical corticosteroids may be adequate in a few patients, but the activity of the disease waxes and wanes, and slow progression should not lead to therapeutic complacency. Oral retinoids can be effective. Alternative therapies include the other oral agents used to treat lupus; however, there are fewer data regarding their use in lichen planopilaris. As in lupus, topical tazarotene and topical macrolactams are generally disappointing. Biologics have been suggested as therapy, but onset of lichen planopilaris has been noted during etanercept therapy.

Hot comb alopecia and central centrifugal cicatricial alopecia

Hot comb alopecia was reported in the late 1960s as a scarring alopecia seen in black women who straightened their hair with hot combs for cosmetic purposes. It develops characteristically on the crown and spreads peripherally to form a large oval area of partial hair loss. The hot petrolatum used with the iron was thought to cause thermal damage to the hair follicle. However, Sperling et al reported a similar-appearing scarring alopecia in both men and women who did not report the use of hot combs. Some authors now regard hot comb alopecia, central centrifugal cicatricial alopecia (CCCA), and idiopathic pseudopelade to be one entity or overlapping entities that can be indistinguishable.

CCCA is seen most commonly in African American women, is slowly progressive, usually begins in the crown, and advances to the surrounding areas (Fig. 33-15). The term is often used as a broad category that includes cases once classified as hot comb alopecia and central elliptical pseudopelade in white women. Some patients will demonstrate crops of crusts at the periphery of the patches, a feature of folliculitis decalvans. Treatment of CCCA is difficult and often unsatisfactory. Discontinuation of chemical and heat processing, and reduction of traction are routinely recommended, but the effectiveness of these recommendations has yet to be substantiated. Cases with overlapping features of folliculitis decalvans may respond to long-term antibiotic therapy and topical corticosteroids. In such overlapping cases, the histology shows a lymphocytic infiltrate during the chronic stage, but periodic crops of pustules demonstrate a neutrophilic folliculitis.

Neutrophil-mediated disorders

Folliculitis decalvans

Folliculitis decalvans presents with crops of pustules that result in cicatricial alopecia. Successive crops of pustules, crusts, or erosions lead to expansion of the alopecic patches. Staphylococci are sometimes cultured from the lesions, and some authors have suggested that folliculitis decalvans merely represents a chronic staphylococcal infection. It is more likely that follicular destruction is the result of an abnormal suppurative immune response. Staphylococci and other organisms probably play a role in inciting the response. The lesions often respond to long-term treatment with tetracycline. The improvement may reflect the antineutrophil effects of the drug or its antimicrobial effects. Many patients also respond to other forms of antistaphylococcal therapy, but the lesions generally recur after the antibiotic is discontinued. Chronic antibiotic treatment generally results in a continued response. Some sustained responses have been noted after combination therapy with rifampin and clindamycin. Rifampin alone has been used, but may promote the emergence of resistance. Selenium sulfide shampoo and topical corticosteroids may be useful as adjunctive therapy. Oral retinoids, oral and topical fusidic acid, and oral zinc sulphate have sometimes produced sustained responses.

A variant of folliculitis decalvans occurs in African American patients who present with pseudofolliculitis of the beard, acne keloidalis nuchae, and scarring alopecia in the vertex and parietal scalp. The scalp demonstrates ingrown hairs, crops of pustules or crusts, and permanent scarring alopecia. While pseudofolliculitis barbae is generally accepted to be the result of ingrown hairs, the pathogenesis of acne keloidalis nuchae remains in question. Histologically, ingrown hairs are common in advanced lesions. Early lesions may not demonstrate the hair. Some patients merely develop small papules on the nape of the neck, while others develop pustules, crusts, and progressive alopecia. This latter group overlaps with folliculitis decalvans.

Acne necrotica

Acne necrotica presents with discrete excoriated follicular papules in the scalp. Biopsy demonstrates an inflammatory crust and suppurative folliculitis. Usually there is no associated scarring alopecia, but occasional cases overlap with folliculitis decalvans.

Erosive pustular dermatitis of the scalp

This often presents as expanding eroded patches with moist granulation tissue (Fig. 33-16). The lesions often follow trauma or a surgical procedure and tend to be chronic and progressive. They respond best to class I topical corticosteroids.

Dissecting cellulitis (perifolliculitis capitis abscessens et suffodiens of Hoffman)

This often coexists with acne conglobata and hidradenitis suppurativa. It may also occur with folliculitis decalvans. The lesions are deep, boggy, and suppurative (Fig. 33-17). They may respond to tetracyclines, retinoids, and intralesional corticosteroids.

Tufted folliculitis

Tufted folliculitis presents with doll's hair-like bundling of follicular units. It is seen in a wide range of scarring conditions, including chronic staphylococcal infection, chronic lupus erythematosus, lichen planopilaris, Graham Little syndrome, folliculitis decalvans (Fig. 33-18), acne keloidalis nuchae, immunobullous disorders, and dissecting cellulitis. Compound hairs (two or more hairs sharing a common infundibulum) occur physiologically on the scalp and legs. They are common in the occipital scalp. Recurrent staphylococcal infection is more common in patients with many compound hairs and commonly leads to tufted folliculitis.

Other forms of permanent alopecia

Pseudopelade of Brocq

Also known as alopecia cicatrisata, this is a rare form of cicatricial alopecia in which destruction of the hair follicles produces multiple round, oval, or irregularly shaped, hairless, cicatricial patches of varying sizes. They are usually coin-sized and are white or slightly pink in color, with a smooth, shiny, marble-like or ivory, atrophic, “onion skin” surface. Interspersed in the patches may be a few spared follicles with hairs growing from them. A clinical inflammatory stage is completely absent. No pustules, crusts, or broken-off hairs are present. The onset is, as a rule, insidious, with one or two lesions appearing on the vertex. The condition affects females three times more commonly than males, and has a prolonged course. In advanced cases large irregular patches are formed by coalescence of some of the many small macules, a pattern referred to as “footprints in the snow.” The alopecia is permanent and the disease is slowly progressive. Histologically, the majority of patients with clinical lesions of pseudopelade demonstrate true scarring (indicated by loss of elastic tissue) in a wedge-shaped pattern in the superficial dermis. The pattern is similar to that seen in lichen planopilaris and suggests that many cases classified as pseudopelade represent an end stage of lichen planopilaris. A subset of patients, however, demonstrates no perifollicular or interfollicular scarring at all. This subset has been called idiopathic pseudopelade. It shows significant clinical overlap with CCCA. In these patients, the dermis is contracted into a thin band of dense collagenous tissue. Elastic fibers are intact and quite thick as a result of elastic recoil related to dermal contraction. Fibrous tract remnants are wide and hyalinized with an intact elastic sheath. Lymphoid and neutrophilic inflammation is absent, but loss of the inner and outer root sheaths with subsequent hair fiber granuloma formation is noted. Sebaceous glands are decreased or absent, as they are in most forms of permanent alopecia. DIF is negative.

The end stage of many forms of cicatricial alopecia can resemble pseudopelade clinically, but, like lichen planopilaris, they demonstrate distinct patterns of elastic tissue loss in the dermis. Folliculitis decalvans is distinguished by periodic crops of pustules or crusts at the periphery of the alopecic patches. It produces superficial wedge-shaped scars similar to those of lichen planopilaris.

Topical and intralesional corticosteroids and long-term tetracycline in anti-inflammatory doses may be tried but are not often successful. The disease usually reaches an inactive end stage after many years.

Traction alopecia

Traction alopecia occurs from prolonged tension on the hair, either from wearing the hair tightly braided or in a ponytail, pulling the hair to straighten it, rolling curlers too tightly, or from the habit of twisting the hairs with the fingers. Traction alopecia most commonly involves the periphery of the scalp, especially the temples and above the ears (Fig. 33-19).

Sarcoidosis

Sarcoidosis of the scalp presents with diffuse or patchy hair loss. The involved scalp is often indurated and a raised peripheral border may be present. The lesions are often red–brown in color and may have an apple jelly appearance with diascopy. Biopsy reveals noncaseating granulomas. Treatment is as for other forms of sarcoidosis.

Pressure alopecia

Pressure alopecia occurs in adults after prolonged pressure on the scalp during general anesthesia, with the head fixed in one position. It may also occur in chronically ill persons after prolonged bed rest in one position (Fig. 33-20), which causes persistent pressure on one part of the scalp. It probably arises because of pressure-induced ischemia.

Tumor alopecia

Tumor alopecia refers to hair loss in the immediate vicinity of either benign or malignant tumors of the scalp. Syringomas, nerve sheath myxomas, and steatocystoma multiplex are benign tumors that may be limited to the scalp and cause alopecia. Alopecia neoplastica is the designation given to hair loss from metastatic tumors, most often from breast or renal carcinoma (Fig. 33-21).

Keratosis pilaris atrophicans

Keratosis pilaris atropicans includes many forms of keratosis pilaris with cicatricial alopecia. Variants include keratosis pilaris atrophicans faciei, atrophoderma vermiculatum, keratosis follicularis spinulosa decalvans, and ichthyosis follicularis.

Keratosis pilaris atrophicans faciei (ulerythema ophryogenes, keratosis pilaris rubra atrophicans faciei, folliculitis rubra, lichen pilare, or xerodermie pilaire symmétrique de la face) begins in infancy as follicular papules with perifollicular erythema. Initially, the lesions are restricted to the lateral eyebrows. With time, they spread to involve the cheeks and forehead. There may be associated keratosis pilaris on the extremities and buttocks. The condition may also be associated with an atopic diathesis, ectodermal dysplasia, or Noonan syndrome.

Atrophoderma vermiculatum (acne vermoulanti, honeycomb atrophy, folliculitis ulerythema reticulata, ulerythema acneiforme, folliculitis ulerythematous reticulata, atrophodermia reticulata symmetrica faciei, atrophoderma reticulatum) presents with erythematous follicular papules on the cheeks in childhood. With time, the lesions develop into pit-like depressions (reticulate atrophy). Autosomal-dominant inheritance has been described. This condition generally spares the scalp and eyebrows.

Keratosis follicularis spinulosa decalvans is a rare X-linked disorder described by Siemens in 1926. The gene has been mapped to Xp21.2–p22.2. It begins in infancy with keratosis pilaris localized on the face, and then evolves to more diffuse involvement. Progressive cicatricial alopecia occurs on the scalp, eyebrows, and sometimes eyelashes. The alopecia starts during childhood, and active disease may remit during the early teenage years. Corneal and conjunctival inflammation, corneal dystrophy, and blepharitis occur, and photophobia is usually a prominent finding.

Ichthyosis follicularis also demonstrates extensive spiny follicular hyperkeratosis, permanent alopecia, and photophobia. Palmar plantar keratosis, nail deformities, atopy, and recurrent cheilitis have been described.

Atrichia with papular lesions

Atrichia with papular lesions is a rare autosomal-recessive disorder with early onset of atrichia, followed by a papular eruption appearing within the first years of life. The condition has been linked to chromosome 8p21 and mutations have been detected in what is now referred to as the hairless gene. It is discussed in more detail in  Chapter 27.

 

33.2 Diseases of skin apendages

Posted by Dr.Md.Hadiuzzaman on February 12, 2013 at 12:30 AM Comments comments (0)

Pattern alopecia (androgenetic alopecia)

Male-pattern baldness

Male-pattern alopecia or male-pattern androgenetic alopecia (common baldness) shows itself during the teens, twenties, or early thirties with gradual loss of hair, chiefly from the vertex and frontotemporal regions. The process may begin at any time after puberty, and the presence of “whisker” or kinky hair may be the first sign of impending male-pattern alopecia. The anterior hairline recedes on each side, in the Geheimratswinkeln (“professor angles”;), so that the forehead becomes high. Eventually, the entire top of the scalp may become devoid of hair. Several patterns of this type of hair loss occur, but the most frequent is the biparietal recession with loss of hair on the vertex. The rate of hair loss varies among individuals. Sudden hair loss may occur in the twenties and then proceed relentlessly, though very slowly, for a number of years. The follicles produce finer and lighter hairs with each hair cycle until terminal hairs are eventually replaced by vellus hairs. During evolution of the process, hair shafts vary significantly in diameter. The parietal and occipital areas are usually spared permanently from this process of progressive miniaturization.

Early-onset male-pattern alopecia is related to the androgen receptor gene. There is no doubt that inherited factors and the effect of androgens such as dihydrotestosterone on the hair follicle are important. Arguments for regarding the inheritance as polygenic include the high prevalence, gaussian curve of distribution in the population, increased risk with number of affected relatives, increased risk in relatives of severely affected women compared with mildly affected, and greater import of an affected mother than an affected father. The possibility that the early onset (before the age of 30) and later onset (after the age of 50) forms may be inherited separately by single genes is also hypothesized.

Male-pattern alopecia is dependent on adequate androgen stimulation and appears to be related to the androgen receptor gene. Eunuchs do not develop baldness if they are castrated before or during adolescence. If they are given androgen therapy, baldness may develop. The 5-α reduction of testosterone is increased in the scalp of balding individuals, yielding increased dihydrotestosterone. Androgen-inducible transforming growth factor (TGF)-β1 derived from dermal papilla cells appears to mediate hair growth suppression. In congenital 5-α-reductase deficiency, the type 2 isoenzyme is lacking and baldness does not occur. Pattern alopecia does occur in males with X-linked ichthyosis, indicating that steroid sulfatase is not critical for the production of alopecia.

Progressive shortening of the anagen phase of hair growth is noted as the hair shaft diameter decreases, so hairs are not only narrowing, but are becoming shorter. A higher proportion of telogen hairs in the affected area results in greater telogen shed. There may also be an increase in the duration of the lag phase between telogen and anagen (the kenogen lag phase).

Histologically, a decrease in anagen and increase in telogen follicles is present. Follicular miniaturization and variability in shaft diameter are noted. These features are particularly evident in transverse sections. Below the level of the miniaturized or telogen follicle, a vascular or fibromucinous fibrous tract remnant is present. These tracts appear numerous in cross-section. Many mast cells may be noted in the fibrous tract remnant, but inflammatory cells are absent. Sebaceous glands may be enlarged, and hair thinning may be associated with solar elastosis. Sparse lymphoid inflammation with spongiosis may be noted at the level of the follicular infundibulum. This may represent associated seborrheic folliculitis. A sparse lymphoid infiltrate may also be noted at the level of the hair bulge.

Miniaturized human hair follicles grafted on to immunodeficient mice can quickly regenerate and grow as well as or better than terminal follicles from the same individual. This suggests that even advanced pattern alopecia may be reversible. Unfortunately, available pharmacologic interventions produce little effect in advanced pattern alopecia.

Minoxidil, an oral hypotensive drug that causes hypertrichosis when given systemically, is available as topical solutions (Rogaine). Minoxidil promotes the survival of dermal papilla cells, prolongs anagen phase, and results in enlargement of shaft diameter. Clinically, apparent success is best in early cases (less than 10 years) of limited extent (bald area of less than 10 cm diameter on the vertex) in whom pretreatment hair density is above 20 hairs/cm2. Minoxidil is available without a prescription as a 2% or a 5% solution. With the 2% solution, 26% of men studied showed moderate to dense regrowth, while 33% showed minimal regrowth after 4 months. Studies show a 45% increase in hair weight with the 5% solution compared to the 2% solution. In those who respond, regrowth can occur as early as 2 months after the first application. Those who respond must continue to use minoxidil indefinitely to maintain a response.

Finasteride, a type 2 5-α-reductase inhibitor, given as a 1 mg tablet daily, is effective in preventing further hair loss and in increasing the hair counts to the point of cosmetically appreciable results in men aged 18–41 with mild to moderate hair loss at the vertex, in the anterior midscalp, and in the frontal region. It has been shown to stop hair loss in up to 90% of men for at least 5 years. Approximately 65% of men demonstrate hair regrowth. As with monoxidil, continued use of the product is required to sustain benefits. Hair patterning on the temples is not improved. It has been shown to lower dihydrotestosterone in the scalp and the serum of treated patients. Hair growth will be evident only after 6 months or more on the drug. If no effect is seen after 12 months, further treatment is unlikely to be of benefit. In one study, regimens that included finasteride were more effective than minoxidil alone, and therapeutic efficacy was enhanced by combining the two drugs. Short-term side effects related to finasteride are infrequent; however, the need to take this medication indefinitely suggests that study of long-term side-effect profiles is critical. A prostate cancer prevention trial with a different dosage form of the same drug showed a decrease in the incidence of cancer. However, those cancers that did occur in the treatment group had a higher average Gleason score. This could be because only lower-grade cancers were prevented. Dutasteride blocks both type 1 and type 2 5-α-reductase, and is effective in the treatment of male-pattern hair loss. Other treatments that show some promise in preliminary studies include fluridil (a topical antiandrogen that suppresses the human androgen receptor) and hormone-enriched topical cell culture medium. Hair transplantation using micrografts of hair follicles from the occipital area to the anterior scalp may satisfactorily recreate hairlines and give excellent cosmetic results.


Female-pattern alopecia (androgenetic alopecia in women)


Women generally have diffuse hair loss throughout the apical scalp with the part wider anteriorly. There is typically sparing of the frontal hairline, although a subset of women exhibits a “male” pattern of temporal recession. Although maintenance of the frontal hairline is the rule in women, a progressive decrease in hair density from the vertex to the front of the scalp does occur. The midline part is an important clinical clue, revealing a “Christmas tree pattern” of hair loss with the part tapering from the anterior to posterior scalp. The BASP classification has been suggested as a single hair loss classification scheme for use in men and women. It is based on basic (BA) types representing the shape of the anterior hairline, and specific (SP) types representing the density of hair on distinct areas (frontal and vertex). This is important because patients of either sex may demonstrate male or female patterns of alopecia. Phototrichograms and measurement of shaft diameter can be used to assess female-pattern alopecia. The same basic changes—reduced hair density and diameter, and diminished anagen and increased telogen hair—occur in women as in men. Sebaceous gland hyperplasia may be present, but is less common than in men. Transverse histologic sections demonstrate variability in the size of hair follicles (anisotrichosis).

The cause is now believed to be a genetic predisposition with an excessive response to androgens. Both women and men with pattern alopecia have higher levels of 5-α-reductase and androgen receptor in frontal hair follicles compared to the levels in occipital follicles. There is also evidence suggesting a hierarchy of androgen sensitivity within follicular units. Follicular miniaturization relates to unrepaired DNA damage and a reduced proliferation rate of matrix keratinocytes. Smoking may be an independent risk factor. Most women with pattern alopecia have normal menses and fertility. If other evidence of androgen excess is present, such as hirsutism, menstrual irregularities, or acne, or if the onset is sudden, evaluation as outlined for hirsutism (see below) should be performed. Men with spinal and bulbar muscular atrophy (Kennedy disease), an X-linked neurodegenerative disease caused by an expansion of a polymorphic tandem CAG repeat within the androgen receptor gene, have a decreased incidence of pattern alopecia.

Topical minoxidil is of benefit. Although some data suggest that 5% minoxidil may be of greater benefit than 2% minoxidil, the evidence is mixed. Given the higher cost of 5% minoxidil, the 2% formulation may be the best choice for many women. Oral antiandrogens, including spironolactone and cyproterone acetate, have been used to treat androgenetic alopecia in women. In one study, cyproterone acetate was more effective than minoxidil when there were other signs of hyperandrogenism, hyperseborrhea, and menstrual abnormalities, and when the body mass index was high. When these other factors were absent, minoxidil was the more effective treatment.

Treatment with finasteride is of no benefit for most women, although the subset with temporal recession may show some benefit. Finasteride treatment is contraindicated in women who may become pregnant. Hair transplantation, wigs, or interwoven hair may give satisfactory cosmetic results. In a pilot study, topical melatonin appeared to prolong anagen phase and may prove to be of some benefit. In some women, telogen effluvium may produce worsening of pre-existing pattern alopecia. Reversible causes of telogen effluvium, such as seborrheic dermatitis, nutrient deficiency, and thyroid disease, should be addressed.

Trichotillomania (trichotillosis)

Trichotillomania is the compulsive practice of plucking hair from the scalp, brows or eyelashes. Typical areas are irregular patches of alopecia that contain hairs of varying length. The scalp has a rough texture, resulting from the short remnants of broken-off hairs. Trichotillomania is seen mostly in girls under the age of 10, but boys, or adults of either sex, may engage in the practice also. Some patients relate exquisite pain localized to a follicle that can only be relieved by plucking the hair.

When speaking with a patient with characteristic areas of alopecia, it has been suggested that it be asked not if but rather how removal of the hair is done. If this fails to uncover a history of hair pulling, shaving a 3 cm2 area in the involved part of the scalp will result in hairs too short for plucking, and normal regrowth in the “skin window” within 3 weeks. Finally, a biopsy, especially if cut horizontally, may demonstrate empty anagen follicles, catagen hairs, pigment casts within the infundibulum, trichomalacia, and hemorrhage. Alopecia areata shares many of these histologic features, and care must be taken to search for the presence of peribulbar lymphocytes or inflammatory cells within the fibrous tract remnants.

Trichotillomania is usually a manifestation of an obsessive–compulsive disorder, but may also be associated with depression or anxiety. It may be associated with compulsive swallowing of the plucked hairs (trichophagia), and may result in formation of a gastric bezoar. Behavior modification, psychotherapy, and appropriate psychopharmacologic medication (such as serotonin-reuptake inhibitors) may be helpful. Valproic acid, quetiapine and naltrexone have been reported as effective in some patients.

 Other forms of noncicatricial alopecia

Alopecia syphilitica may have a typical moth-eaten appearance on the occipital scalp (Fig. 33-7), may show a generalized thinning of the hair, or may resemble alopecia areata. Other areas such as the eyebrows, eyelashes, and body hair may be involved. The alopecia may be the first sign of syphilis.

Follicular mucinosis (alopecia mucinosa) most commonly occurs on the scalp or beard area and manifests as a boggy red plaque or hypopigmented patch with hair loss. Comedone-like lesions may exude mucin when expressed. Biopsy demonstrates deposition of mucin in the outer root sheath and sebaceous glands. The mucin stains as hyaluronic acid, rather than epithelial sialomucin. Primary cases (unassociated with underlying disease) usually occur as localized lesions of the head or neck. Young people are primarily affected. The secondary type is associated with mycosis fungoides-type cutaneous T-cell lymphoma or a chronic inflammatory skin disease. Lesions associated with mycosis fungoides are generally widespread and chronic, and occur in older patients.

Vascular or neurologic alopecia, most often of the lower extremities, may be seen in diabetes mellitus or atherosclerosis. In meralgia paresthetica there may be alopecia of the anesthetic area of the outer thigh.

Endocrinologic alopecia may occur in various endocrinologic disorders. In hypothyroidism the hair becomes coarse, dry, brittle, and sparse. The proportion of telogen hairs has been shown to be 3–7 times higher than the normal 10%. In hyperthyroidism the hair becomes extremely fine and sparse. Oral contraceptives have been implicated in some instances of androgenetic alopecia. It develops in predisposed women who are usually taking androgenic progestogens. It is advisable to discontinue the androgen-dominant pill and substitute an estrogen-dominant oral contraceptive. Some women develop telogen effluvium 2–4 months after discontinuing anovulatory agents, which is analogous to postpartum alopecia.

Congenital alopecia occurs either as total or partial loss of hair, or a lack of initial growth, accompanied usually by other ectodermal defects of the nails, teeth, and bone. The hair is light and sparse, and grows slowly. Congenital triangular alopecia (Fig. 33-8) and aplasia cutis congenita are examples of congenital localized absence of hair, while hidrotic ectodermal dysplasia is an example of a diffuse abnormality of hair associated with dental and nail changes.

Lipedematous alopecia consists of thickening of the scalp that gives the impression of thick cotton batting. The hair may be normal or shortened and sparse. Biopsy shows an increase in thickness of the subcutaneous fat and variable lymphoid inflammation. This disease appears to affect black persons primarily.

 


 

33.1 Diseases of skin apendages

Posted by Dr.Md.Hadiuzzaman on February 12, 2013 at 12:30 AM Comments comments (0)

Diseases of the Skin Appendages

Diseases of the hair

Normal human hairs can be classified according to cyclical phases of growth. Anagen hairs are growing hairs, catagen hairs are those undergoing transition from the growing to the resting stage, and telogen hairs are resting hairs, which remain in the follicles for variable lengths of time before they fall out (teloptosis). The lag period between loss of the telogen hair and growth of a new anagen hair has been referred to as kenogen.

Anagen hairs grow for about 3 years (1000 days), with a range between 2 and 6 years. The follicular matrix cells grow, divide, and become keratinized to form growing hairs. As the matrix produces the hair shaft, it incorporates substances that may be useful in medical or forensic analysis. Catagen hairs are in a transitional phase, lasting 1 or 2 weeks, in which all growth activity ceases, with the eventual formation of the telogen “club” hair. Many apoptotic cells are present in the outer root sheath of the catagen hair as it involutes. Telogen club hairs are resting hairs, which continue in this state for 3–5 months (about 100 days) before they are released.

Among human hairs plucked from a normal scalp, 85–90% are anagen hairs and 10–15% are telogen hairs. Catagen hairs normally comprise less than 1% of scalp hairs. It has been estimated that the scalp normally contains about 100 000 hairs, and the average number of hairs shed daily is 100–150. The hair growth rate of terminal hairs is about 0.37 mm/day. Contrary to popular belief, neither shaving nor menstruation has any effect on hair growth rate. The average uncut scalp hair length is estimated to be 25–100 cm, although exceptional hairs may be as long as 170 cm (70 inches).

Human hair is also designated as lanugo, vellus, or terminal hair. Lanugo hair is the fine hair present on the body of the fetus. This is replaced by the vellus and terminal hairs. Vellus hairs are fine and usually light-colored, and have a narrow hair shaft thinner than the width of the inner root sheath. Terminal hairs are coarse, thick, and dark, except in blonds. Hair occurs on all skin surfaces except the palms, soles, labia minora, lips, nails, glans, and prepuce. Terminal hairs are commonly present on a man's face, chest, and abdomen, but vellus hairs usually predominate on these sites in women.

Causes of alopecia are generally divided into the broad categories of cicatricial and noncicatricial alopecia. The evaluation should take into account the patient's age and ethnicity. Examination of hair shafts can establish a diagnosis of trichodystrophy. Hair counts, hair pull, and hair pluck (trichogram) can establish the degree of hair shedding, the type of hair that is shed, and the anagen to telogen ratio. Biopsies can also the determine anagen to telogen ratio, and provide information regarding the potential for regrowth, as well as providing a diagnosis. Biopsies are particularly valuable in the evaluation of cicatricial alopecia. Often, a correct diagnosis hinges on a synthesis of clinical, histologic, serologic, and immunofluorescent data.


Noncicatricial alopecia

Alopecia areata

Clinical features

Alopecia areata (in French, pelade) is characterized by rapid and complete loss of hair in one or more round or oval patches, usually on the scalp, bearded area, eyebrows, eyelashes, and less commonly, on other hairy areas of the body. Often the patches are from 1 to 5 cm in diameter. A few resting hairs may be found within the patches. Early in the course there may be sparing of gray hair, and white hairs are rarely affected. Sudden whitening of hair may represent widespread alopecia areata in a patient with salt and pepper hair. In about 10% of cases of alopecia areata, especially in long-standing cases with extensive involvement, the nails develop uniform pits that may form transverse or longitudinal lines. Trachyonychia, onychomadesis, and red or spotted lunulae occur, but less commonly. Dermoscopic examination typically demonstrates diffuse, round, or polycyclic perifollicular yellow dots.

Complete loss of scalp hair is referred to as alopecia totalis, and complete loss of all hair as alopecia universalis. In most cases, hair loss is confined to the scalp and is patchy in distribution. Loss may occur confluently along the temporal and occipital scalp (ophiasis) (Fig. 33-1) or on the entire scalp except for this area (sisaipho). Rarely, alopecia areata may present in a diffuse pattern that may mimic pattern alopecia. Clues to the correct diagnosis include a history of periodic regrowth, nail pitting, and the presence of tapered fractures or exclamation point hairs (Fig. 33-2). Alopecia areata generally presents as an anagen effluvium, with an inflammatory insult to the hair matrix resulting in tapering of the hair shaft and in fracture of anagen hairs. As the hair miniaturizes or converts from anagen to telogen, the remaining lower portion of the hair rises above the level of the scalp, producing the exclamation point hair.

 Alopecia areata is associated with a higher incidence than usual of atopic dermatitis, Down syndrome, lichen planus, and autoimmune diseases, such as systemic lupus erythematosus (SLE), thyroiditis, diabetes mellitus, myasthenia gravis, and vitiligo. However, most cases of alopecia areata occur without associated disease, and routine screening for these disorders is of little value unless prompted by signs or symptoms.

Migratory poliosis of the scalp may represent a forme fruste of alopecia areata. Patients with this disorder present with migrating circular patches of white hair, but never lose hair. The histology resembles alopecia areata.

Etiologic factors

The preponderance of evidence supports an autoimmune etiology. Oligoclonal and autoreactive T lymphocytes are present in the peribulbar inflammatory infiltrate, and many patients respond to immune-modulating drugs. Affected alopecia areata scalp skin grafted on to nude mice with severe combined immunodeficiency demonstrates loss of infiltrating lymphocytes and hair growth. In this model, injecting T lymphocytes with scalp homogenate can reproduce the alopecia. Follicular melanocytes substitute for scalp homogenates to produce alopecia areata in this model, providing evidence that follicular melanocytes are the targets for activated T cells in this disease. This hypothesis is also supported by the observations that white hair is rarely affected and regrowing hair is often depigmented.

In early alopecia areata, the perifollicular and intrafollicular inflammatory infiltrate is composed of activated CD4+ and CD8+ T cells, together with macrophages and Langerhans cells. The early phase of hair loss appears to be mediated by type 1 cytokines, including interleukin (IL)-2, interferon (IFN)-γ, and tumor necrosis factor (TNF)-α. The hair bulb normally represents an area of relative immune privilege during anagen, as evidenced by a very low level of expression of major histocompatibility complex (MHC) class Ia antigens. This immune privilege may prevent antigen recognition by autoreactive CD8+ T cells. Alopecia areata may be related to collapse of this immune privilege. IFN-γ-deficient mice are resistant to alopecia areata.

Onset of disease after Epstein–Barr virus infectious mononucleosis has been reported. Neuropeptides modify immune reactivity and may have a role in the disease. Heredity also plays a part. Overall, nearly 25% of patients have a positive family history; there are reports of twins with alopecia areata. Patients with “early onset, severe, familial clustering alopecia areata” have a unique and highly significant association with the HLA antigens DR4, DR11, and DQ7. The “later onset, milder severity, better prognostic” subsets of patients have a lower frequency of familial disease and do not share these HLA antigens. Familial alopecia areata associated with hereditary thrombocytopenia related to mutations in genes on chromosome 17 has been described. R620W (c.1858C>T, a variant of the protein tyrosine phosphatase nonreceptor 22 gene [PTPN22]) is associated with a variety of autoimmune disorders, including alopecia areata. It is associated with early onset of disease, widespread hair loss, and a positive family history.

HistologyIn early disease there is a lymphoid infiltrate in the peribulbar area of anagen or early catagen follicles. Eosinophils may be present in the infiltrate, and lymphocyte-mediated damage to the bulb produces melanin pigment incontinence in the surrounding stroma. The hair structures enter an abnormal catagen phase, followed by telogen. During this phase, the presence of many catagen hairs and pigment casts within the follicular canal can cause histologic confusion with trichotillomania. In alopecia areata, the follicles eventually miniaturize, appearing as small dystrophic anagen hairs high in the dermis, often with a persistent lymphocytic peribulbar infiltrate. The presence of a peribulbar infiltrate helps to distinguish the miniaturized follicles of alopecia areata from those of androgenetic alopecia. Fibrous tract remnants beneath the miniaturized bulbs of alopecia areata may contain lymphoid cells, eosinophils, and melanin pigment. These findings are never present in trichotillomania or androgenetic alopecia. With time, the lymphocytes disappear, but focal eosinophils and pigment remain. Finally, only focal melanin pigment remains in the fibrous tract remnants. Hair fiber granulomas and scarring never occur. Every histologic feature of alopecia areata may be seen in syphilis. The presence of plasma cells is suggestive of syphilis, but plasma cells are also lacking in about one-third of syphilis biopsies. Plasma cells may be present in biopsies from any form of inflammatory alopecia if the biopsy is taken from the occipital scalp, as this site readily recruits plasma cells.

Differential diagnosis

The sharply circumscribed patch of alopecia with exclamation point hairs at the periphery and the absence of scarring are indicative of alopecia areata. Tinea capitis, androgenetic alopecia, early lupus erythematosus, syphilis, congenital triangular alopecia, alopecia neoplastica, and trichotillomania should be kept in mind when alopecia areata is considered. A biopsy will generally help to distinguish alopecia areata from these other entities, except syphilis, which may be indistinguishable. In endemic areas of southwest Asia, Pheidole ants shear hair shafts during the night, resulting in overnight loss of clumps of hair. The resulting round patches of hair loss closely mimic alopecia areata.

Treatment

The natural course of the hair loss is highly variable. Some patches will regrow in a few weeks without any treatment. Various treatments can induce growth, but the inherent risks and cost must be weighed against the benefit of earlier regrowth. In his series of 63 consecutive responders to a follow-up questionnaire, Arnold found that, after reassurance only, hair had regrown in all but four patients after 1 year and in all but one after 2 years. The great majority had recovered in 3 months after their only office visit. Therefore, anecdotal reports of success must be interpreted carefully in the light of the high rate of spontaneous recovery.

Intralesional injections of corticosteroid suspensions are the treatment of choice for localized, cosmetically conspicuous patches, such as those occurring in the frontal hairline or involving an eyebrow. Injections of triamcinolone, 2–10 mg/mL, are typically given intradermally or in the superficial subcutaneous tissue. Large volumes and higher concentrations of triamcinolone present a greater risk of atrophy. Injection under significant pressure or with a small-bore syringe increases the likelihood of retinal artery embolization. High-strength topical steroids may be used as a safer first-line therapy, but are less reliable than injections. Several investigators have reported the use of pulsed oral corticosteroids in rapidly progressing or widespread disease. However, long-term treatment is frequently needed to maintain growth, and the attendant risks should be carefully weighed against the benefits. In a study of 66 patients aged 9–60 years, monthly methylprednisolone was administered at a dose of 500 mg/day during 3 days or 5 mg/kg twice a day over 3 days in children. More than 60% of patients with widespread patchy alopecia responded. Half of the patients with alopecia totalis had a good response, while a quarter of those with universal alopecia responded. Patients with ophiasic alopecia areata did not respond.

Induction of contact sensitivity to squaric acid dibutyl ester, dinitrochlorobenzene, and diphencyprone can be useful in refractory cases. In mice, contact immunotherapy is associated with a decrease in cutaneous activated T cells, a reduction in intrafollicular CD8+ lymphocytes, and reduced expression of CD44v3+ and CD44v10+ cells. These results suggest that blockade of leukocyte trafficking and extravasation is an important mechanism of action. Topical or oral methoxsalen and ultraviolet A (PUVA) therapy is an option for refractory or widespread lesions. Short-contact topical anthralin 1% cream (applied for 15–20 min and then shampooed off) can be of benefit. Topical minoxidil may be combined with other treatments or utilized as a single agent. Preliminary results suggest methotrexate and sulfasalazine may be beneficial. Biologics have produced mixed, and largely disappointing, results, and alopecia areata has developed during biologic therapy for other conditions. The 308 nm xenon chloride excimer laser (300–2300 mJ/cm2/session) has been reported to produce regrowth after 11 and 12 sessions over a 9–11-week period. Periocular pigmentation is associated with use of travoprost for eyelash disease. Therapeutic results are mixed.

Alopecia areata can cause tremendous psychological stress. Education about the disease process, cosmetically acceptable alternatives (especially information about wigs), and research into innovative therapies should all be made available to the patient. In addition to the information conveyed by the dermatologist, an excellent resource is the National Alopecia Areata Foundation (NAAF): E-mail: info@naaf.org, website: www.naaf.org.

Prognosis

The tendency is for spontaneous recovery in patients who are postpubertal at onset. At first, the regrowing hairs are downy and light in color; later, they are replaced by stronger and darker hair with full growth. Predictors of a poor prognosis are the presence of atopic dermatitis, childhood onset, widespread involvement, ophiasis, duration of longer than 5 years, and onychodystrophy. Acute diffuse and total alopecia is a newly defined subtype of alopecia areata that occurs in young adults and has a good prognosis.

 Telogen effluvium

Telogen effluvium presents with excessive shedding of normal telogen club hairs. This excessive shedding of telogen hairs has several possible mechanisms. It most commonly occurs 3–5 months after the premature conversion of many anagen hairs to telogen hairs induced by surgery, parturition, fever, drugs, dieting, or traction. Local patches of early telogen conversion may be induced by papulosquamous diseases affecting the scalp. Alternatively, follicles may remain in prolonged anagen rather than normally cycling into telogen. This occurs during pregnancy. On delivery, many follicles are then released simultaneously into telogen, and shedding occurs 3–5 months later. Prolongation of telogen also occurs during pregnancy, and results in an initial wave of hair loss soon after delivery or heralding early termination of a pregnancy. Shortening of the anagen phase occurs in pattern (androgenetic) alopecia, and results in telogen effluvium. Normally, anagen lasts about 1000 days and telogen about 100 days. This results in a 10:1 ratio of anagen to telogen hairs in the scalp. With progression of pattern alopecia, anagen shortens, and the ratio of anagen to telogen hairs falls. A greater proportion of hairs is in telogen at any one time, resulting in a chronic increase in telogen shed. Administration of topical minoxidil may produce a telogen effluvium by premature termination of telogen necessary to initiate anagen in responding follicles. This causes early telogen release and a brief telogen effluvium.

Whatever the cause of the telogen loss, the hair is lost “at the root.” Each hair will have a visible depigmented club-shaped bulb and will lack a sheath (Fig. 33-3). In most cases, loss is diffuse. Patients commonly have more than one mechanism for telogen hair loss. Patchy or diffuse telogen may be associated with papulosquamous diseases of the scalp. Perceptible thinning of the hair is more common in patients with pre-existing pattern alopecia. In patients with pattern alopecia, shortening of the hair cycle results in increased telogen shed. Superimposed papulosquamous disease, iron deficiency, or thyroid disease can result in even more telogen shed and accentuates the pattern loss.

Trichodynia is a common symptom in patients with telogen effluvium, as it is in pattern hair loss. Trichodynia often coexists with signs of depression, obsessive personality disorder, and anxiety.

Telogen shed may be estimated by the pull test: grasping 40 hairs firmly between thumb and forefinger, followed by a slow pull that causes minimal discomfort to the patient. A count of more than 4–6 club hairs is abnormal, but the result is influenced by recent shampooing (a count of 2–3 hairs being abnormal in a freshly shampooed scalp), combing, and the phase of telogen effluvium (whether it is resolving or entering a chronic phase). The clip test may also be useful; 25–30 hairs are cut just above the scalp surface and mounted. Indeterminate and telogen hairs are short and of small diameter. Many hairs of this type may be present in telogen effluvium or pattern alopecia. Trichogram evaluation (50 hairs plucked with a Kelly clamp with rubber drains over the teeth) can also provide information on the anagen to telogen ratio.

Age, sex, race, and genetic factors influence the normal average daily hair loss in an individual. A full head of hair numbers about 100 000; of these, approximately 100–150 are lost daily. In telogen effluvium, estimates of loss vary from 150 to more than 400. Patients may be instructed to collect and count the hair daily; however, they should make sure they collect all small hairs and those that come out in washing and in the bed, as well as those present on the comb or brush. When the pull test is positive, hair shed counts are not needed. An alternative is to collect all hairs lost during a 1 min combing session. For this technique, developed by Dr Jeffrey Miller, the patient combs for 1 min prior to shampooing on 3 consecutive days. The patient is instructed to comb from the vertex to the anterior hairline. The normal range of lost hairs with this technique is 10–15. Loss of more than 50 is common in telogen effluvium. Serial 1 min hair counts can be performed to monitor progress.

Telogen effluvium is commonly related to protein or other nutrient deprivation (Fig. 33-4). Assessment of dietary habits and determination of iron saturation and ferritin are the simplest ways to determine nutritional status. Iron replacement is advisable if saturation or ferritin is low, but in one study iron replacement alone did not result in resolution of telogen effluvium. Iron may merely serve as a marker for overall nutritional status. Patients with evidence of deficiency should be given supplements to correct the identified deficiency and encouraged to eat a varied diet. Sources of blood loss, such as menstrual bleeding and gastrointestinal blood loss, should be investigated. Hypothyroidism, allergic contact dermatitis to hair dyes, and renal dialysis with secondary hypervitaminosis A may also be associated with telogen effluvium. Drug-induced telogen effluvium has been noted with the use of aminosalicylic acid, amphetamines, bromocriptine, captopril, carbamazepine, cimetidine, coumarin, danazol, enalapril, etretinate, levodopa, lithium carbonate, metoprolol, metyrapone, pramipexole, propranolol, pyridostigmine, and trimethadione. Postnatal telogen effluvium of infants may occur between birth and the first 4 months of age. Usually, regrowth occurs by 6 months of age. Telogen counts by Kligman in six infants varied from 64% to 87%. He also found a tendency for the alopecia to occur in the male-pattern distribution. Idiopathic chronic telogen effluvium has been described by Whiting in a group of 355 patients (346 women and 9 men) with diffuse generalized thinning of scalp hair. Most were 30–60 years old, and their hair loss started abruptly, with increased shedding and thinning. There was a fluctuating course and diffuse thinning of the hair all over the scalp, accompanied by bitemporal recession. He found high telogen counts on horizontal sections of scalp biopsies and considers these patients to have a chronic form of telogen effluvium. This chronic form may respond to 5% minoxidil solution.

If a 4 mm punch biopsy is performed, 25–50 hairs are normally present for inspection in transverse (horizontal) sections. If more than 12–15% of terminal follicles are in telogen, this indicates a significant shift from anagen to telogen. Pattern (androgenetic alopecia) demonstrates miniaturization, variable hair shaft diameter, and an increased proportion of telogen hairs. Traction alopecia and trichotillosis (trichotillomania) result in an increased number of catagen and telogen hairs. Pigment casts, empty anagen follicles, trichomalacia, and catagen hairs help distinguish these entities from simple telogen effluvium.

No specific therapy is required for most patients with telogen effluvium. In the majority of cases the hair loss will stop spontaneously within a few months and the hair will regrow. Drug-induced telogen effluvium responds to discontinuation of the offending agent. The prognosis is good if a specific event can be pinpointed as a probable cause. Papulosquamous scalp disorders may precipitate telogen hair loss and should be addressed. Iron and thyroid status should be determined if the course is prolonged or if history or physical examination suggests an abnormality. Patients should be encouraged to eat a balanced diet. In a mouse model, sonic stress can produce catagen. This model may be useful in the study of agents for the treatment of telogen effluvium.

 Anagen effluvium

Anagen effluvium usually results from hair shaft fracture. It is frequently seen following the administration of cancer chemotherapeutic agents, such as the antimetabolites, alkylating agents, and mitotic inhibitors. These agents result in temporary shutdown of the hair matrix with resultant tapering of the shaft (Pohl–Pinkus constrictions). Trichograms reveal tapered fractures. Only anagen hairs are affected. The 10% of scalp hairs in telogen have no matrix and are unaffected. The loss tends to be diffuse but not complete. It may resemble pattern alopecia. Severe loss is frequently seen with doxorubicin, the nitrosureas, and cyclophosphamide. When high doses are given, loss of anagen hairs becomes most apparent clinically in 1–2 months. The hair shafts are abruptly narrowed at the time of maximum drug effect, and when the very thin portion reaches the surface, the hair shafts all break at about the same time. With cessation of drug therapy, the follicle resumes its normal activity within a few weeks; the process is entirely reversible. It is apparent that mitotic inhibition merely stops the reproduction of matrix cells but does not permanently destroy the hair. A pressure cuff applied around the scalp during chemotherapy and scalp hypothermia have been reported to prevent such anagen arrest, but as the scalp may be a site of metastasis, it may be better not to spare the scalp from the effects of chemotherapy. Topical minoxidil has been shown to shorten the period of baldness by an average of 50 days.

In addition to the cytotoxic chemotherapeutic agents, various agents, such as isoniazid INH, thallium, and boron may induce anagen effluvium. Anagen effluvium with tapered fractures also occurs in alopecia areata and syphilis. In these diseases, an inflammatory insult to the hair bulb results in Pohl–Pinkus constrictions and tapered fracture.

Anagen loss may also occur at the root. Loose anagen syndrome, described by Price in 1989, is a disorder in which anagen hairs may be pulled from the scalp with little effort. It occurs mostly in blond girls and usually improves with age. The syndrome appears to be related to a defect in the hair cuticle. Instead of anchoring the hair firmly, the cuticle simply folds back like a rumpled sock (Fig. 33-5), allowing the hair shaft to be extracted. Woolly hair can be associated with loose anagen hair syndrome. A keratin mutation, E337K in K6HF, was identified in three of nine families studied. Colobomas have also been associated with loose anagen hair.

Anagen hairs may be easily extracted from active areas of lupus erythematosus and lichen planopilaris. They commonly lack the root sheath that normally surrounds a plucked anagen hair (Fig. 33-6). Anagen effluvium has also been described in lesions of pemphigus.

 


 

33.9 Diseases of nail

Posted by Dr.Md.Hadiuzzaman on February 11, 2013 at 11:05 PM Comments comments (0)

Diseases of the nails

Several general references are available that review a wide spectrum of nail changes.


Nail-associated dermatosesNumerous dermatoses are associated with characteristic, sometimes specific, nail changes. Many are considered elsewhere.

Lichen planus of nailsThe reported incidence of nail involvement in lichen planus varies from less than 1% to 10%. Lichen planus of the nails may occur without skin changes, but 25% with nail disease will have lichen planus at other locations. Although it may occur at any age, most commonly it begins during the fifth or sixth decade of life. The nail plate may be markedly thinned, and at times distinct papules of lichen planus may involve the nailbed. Twenty-nail dystrophy (trachyonychia) may be the sole manifestation of lichen planus. Other nail changes are irregular longitudinal grooving and ridging of the nail plate, thinning of the nail plate, pterygium formation (Fig. 33-38), shedding of the nail plate with atrophy of the nailbed, subungual keratosis, or even onychopapilloma, erythronychia (red streaks), subungual hyperpigmentation, and nail degloving. This latter sign is a newly described entity where there is partial or total shedding of the nail or the entire nail apparatus. The surrounding skin may also slough. This may be caused by trauma, ischemia and gangrene, or severe dermatologic disease such as toxic epidermal necrolysis or lichen planus.

 

 

Fig. 33-38  Pterygium caused by lichen planus.

(Courtesy of Lawrence Lieblich, MD)

The histologic changes of lichen planus may be evident in any individual nail constituent or a combination of them. The one most frequently involved is the matrix.

Treatment is mostly unsatisfactory. Intralesional injection of corticosteroids may be of help in some patients. Digital nerve blocks should be considered before infiltration of the matrix or nailbed. Topical corticosteroids under polyethylene occlusive dressings are usually inadequate. Clobetasol combined with tazarotene may be successful. Oral prednisone (0.5–1 mg/kg for 3 weeks) or oral retinoids in combination with topical steroids applied to the involved sites has been successful in some patients. Tosti et al reported that typical lichen planus of the nails in children responded to 0.5–1 mg/kg/month of intramuscular triamcinolone acetonide given for 3–6 months, until the proximal half of the nail was normalized. Disease recurred in only two patients during the follow-up period. While twenty-nail dystrophy was not treated, patients spontaneously improved; those with idiopathic atrophy of the nails were unchanged. (See  Chapter 12 for additional therapeutic considerations.)

 



Psoriatic nailsNail involvement in psoriasis is common, with reported incidences varying from 10% to 78%. Older patients, those with active exacerbations of disease, and those with psoriatic arthritis are more likely to express nail abnormalities. In the nail plate there may be pits (Fig. 33-39), or much less often, furrows or transverse depressions (Beau's lines), crumbling nail plate, or leukonychia, with a rough or smooth surface. Splinter hemorrhages are found in the nailbed, with reddish discoloration of a part or all of the nailbed, and horny masses. In the hyponychium, subungual hyperkeratosis, oil spots, and a yellowish–green discoloration may occur in the area of onycholysis. Onychomycosis may be closely simulated. The severity of nail disease may correlate with the severity of skin and joint disease. Pustular psoriasis may produce onycholysis, with lakes of pus in the nailbed or in the perionychial areas. Rarely, anonychia may result. Other papulosquamous diseases may affect the nails like psoriasis, with the exception of nail pitting. Reiter's disease, pityriasis rubra pilaris, Sézary syndrome, and acrokeratosis paraneoplastica produce as a rule hypertrophic nails with subungual hyperkeratosis.

Psoriatic nail disease may be a solitary finding or be part of a widespread skin and nail involvement. The treatment options selected depend on the degree of cutaneous and nail involvement. (See  Chapter 10 for additional information and therapeutic options.) Successful systemic treatment of psoriasis will usually also improve or clear the nail changes. Methotrexate, PUVA, cyclosporine, the biologics, or acitretin may be effective. All local therapies have limitations. Intralesional injection of triamcinolone acetonide suspension, 3–5 mg/mL, with a 30-gauge needle is frequently helpful. Digital nerve block facilitates adequate injection. Topical 5-fluorouracil (5-FU) applied to the proximal nailfold has been reported to be effective. It is best to avoid the free edge of the nail when applying 5-FU, as it may cause distal onycholysis. Topical cyclosporine and topical tazarotene 0.1% gel may also be helpful. Topical calcipotriol improves about 50% of patients with localized pustular psoriasis of the nails and may be used as a maintenance treatment after successful intervention with systemic retinoids.

 


Darier's diseaseLongitudinal, subungual, red or white streaks, associated with distal wedge-shaped subungual keratoses, are the nail signs diagnostic for Darier–White disease. Keratotic papules on the dorsal portion of the nailfold may clinically resemble acrokeratosis verruciformis, but histologically have features of Darier's disease. Other nail findings include splinter hemorrhages and leukonychia. All of these findings are less pronounced on the toenails.

ClubbingClubbing is divided into two types: idiopathic and acquired, or secondary. The changes occur not only in the nails but also in the terminal phalanges. The nails bulge and are curved in a convex arc in both transverse and longitudinal directions. The eponychium is thickened. The angle formed by the dorsal surface of the distal phalanx and the nail plate (Lovibond's angle) is approximately 160°; however, with clubbing this angle is obliterated and becomes 180° or greater (Fig. 33-40). There is no diamond-shaped window when the dorsal surfaces of the corresponding finger of each hand are opposed (Schamroth's sign). The soft tissues of the terminal phalanx are bulbous and of are mobile when pressure is applied over the matrix. Thickening of the nailbed is present and can be assessed reliably by a plain radiograph of the index finger.

Idiopathic clubbing is either of the isolated dominantly inherited type or of the pachydermoperiostosis type with its associated findings. In the hereditary isolated type, a homozygous missense mutation in exon 6 of the human HPGD gene encoding NAD(+)-dependent 15-hydroxyprostaglandin dehydrogenase (15-PGDH) has been identified. Secondary (acquired) clubbing is usually a consequence of pulmonary, cardiac, thyroid, hepatic, or gastrointestinal disease. Around 36% of HIV patients has been documented to express clubbed nails. Typically, there is periostitis, with periosteal new bone formation in the phalanges, metacarpals, and distal ulna and radius. This is called hypertrophic osteoarthropathy and is responsible for the painful clubbing. It typically occurs in men with bronchogenic carcinoma. Unilateral or asymmetrical clubbing may also occur in Takayasu arteritis and sarcoidosis.

 


Shell nail syndromeCornelius et al described a shell nail in association with bronchiectasis. The nail resembles a clubbed nail, but the nailbed is atrophic instead of being a bulbous proliferation of the soft tissue.

 



Koilonychia (spoon nails)Spoon nails are thin and concave, with the edges everted so that if a drop of water were placed on the nail, it would not run off (Fig. 33-41). Koilonychia may result from faulty iron metabolism and is one of the signs of Plummer–Vinson syndrome, as well as of hemochromatosis. Spoon nails have been observed in coronary disease, syphilis, polycythemia, and acanthosis nigricans. Familial forms are also known to occur. Other associations include psoriasis, lichen planus, Raynaud disease, scleroderma, acromegaly, hypothyroidism and hyperthyroidism, monilethrix, palmar hyperkeratoses, and steatocystoma multiplex. A significant number of cases are idiopathic. Manual trauma in combination with cold exposure may result in seasonal disease. Sherpas are Tibetan people living in the Nepalese Himalayas, who often serve as porters on mountain-climbing expeditions. Chronic cold exposure, in combination with hypoxemia, may contribute to the high frequency with which koilonychia is observed among them.

 


Congenital onychodysplasia of the index fingersCongenital onychodysplasia of the index fingers is defined by the presence of the condition at birth, index finger involvement (unilateral or bilateral), variable distortion of the nail or lunula, and polyonychia, micronychia, anonychia, hemionychogryphosis, or malalignment. It may also involve adjacent fingers, such as the middle fingers and thumbs. An underlying bone dysplasia may be present beneath the involved nail. Cases have occurred in an autosomal-dominant pattern; other proposed causes include in utero ischemia or exposure to teratogens.

 


TrachyonychiaThe nails may become opalescent, thin, dull, fragile, and finely ridged longitudinally (and as a result, distally notched). When this involves all 20 nails, it is referred to as twenty-nail dystrophy. This latter presentation may be seen at any age from    years to adulthood, although it is most commonly diagnosed in children. It can be idiopathic or caused by alopecia areata, psoriasis, lichen planus, atopy, ichthyosis vulgaris, or other inflammatory dermatoses. Familial forms exist. In some cases spongiosis may be found on nail biopsy. Trachyonychia has also been reported associated with autoimmune processes such as selective IgA deficiency, vitiligo, sarcoidosis, and graft versus host disease. Unilateral involvement may occur in complex regional pain syndrome. Thus it is caused by a heterogenous group of inflammatory conditions. Tazarotene alone or in association with topical steroids may improve the condition. Childhood cases may resolve spontaneously; in one study 50% cleared within 6 years.

 


OnychauxisIn onychauxis the nails are thickened but without deformity (simple hypertrophy). Simple thickening of the nails may be the result of trauma, acromegaly, Darier's disease, psoriasis, or pityriasis rubra pilaris. Some cases are hereditary.

Treatment involves periodic partial or total debridement of the thickened nail plate by mechanical or chemical (40% urea paste) means. Matricectomy and nail ablation are options, as they are in onychogryphosis, congenital nail dystrophies, and chronic painful nails such as recalcitrant ingrown toenails or splits within the medial or lateral third of the nail.

 


OnychogryphosisHypertrophy may produce nails resembling claws or a ram's horn. Onychogryphosis may be caused by trauma or peripheral vascular disorders but is most often caused by neglect (failure to cut the nails for very long periods). It is most commonly seen in the elderly.

Some recommend avulsion of the nail plate with surgical destruction of the matrix with phenol or the CO2 laser, if the blood supply is good.

 


OnychophosisA common finding in the elderly, onychophosis is a localized or diffuse hyperkeratotic tissue that develops on the lateral or proximal nailfolds, within the space between the nailfolds and the nail plate. It may involve the subungual area, as a direct result of repeated minor trauma, and most frequently affects the first and fifth toes. The use of comfortable shoes should be encouraged. The areas involved should be debrided and treated with keratolytics. Emollients are also helpful.

 


AnonychiaAbsence of nails, a rare anomaly, may be the result of a congenital ectodermal defect, ichthyosis, severe infection, severe allergic contact dermatitis, self-inflicted trauma, Raynaud phenomenon, lichen planus, epidermolysis bullosa, or severe exfoliative diseases. Permanent anonychia has been reported as a sequel of Stevens–Johnson syndrome. It may also be found in association with congenital developmental abnormalities, such as microcephaly, and wide-spaced teeth (autosomal-recessive inheritance), the autosomal-dominant Cooks syndrome (bilateral nail hypoplasia of digits 1–3, the absence of nails of digits 4 and 5 of the hands, total absence of all toenails, and absence or hypoplasia of the distal phalanges of the hands and feet), DOOR syndrome (deafness, onycho-osteodystrophy, mental retardation), and the glossopalatine syndrome (abnormal mouth, tongue being attached to the temporomandibular joint).

It may also present as an autosomal-recessive disorder with anonychia as the solitary finding. It has been found to be caused by a mutation in the R-spondin 4 gene. R-spondins are secreted proteins that activate the Wnt/β-catenin signaling pathway. R-spondin 4 is exclusively expressed in the mesenchyme underlying the digit tip epithelium in embryonic mice.

 


OnychoatrophyFaulty underdevelopment of the nail may be congenital or acquired. The nail is thinned and small. Vascular disturbances, epidermolysis bullosa, lichen planus, Darier's disease, multicentric reticulohistiocytosis, and Hansen's disease may cause onychoatrophy. It is also seen in congenital syndromes such as Apert, Goltz, Turner, Ellis–van Creveld, nail–patella, dyskeratosis congenita, cartilage–hair hypoplasia, progeria, hypohidrotic ectodermal dysplasia, incontinentia pigmenti, popliteal web, trisomy 13 and trisomy 18, and as a side effect of etretinate therapy.

 



OnychomadesisOnychomadesis is a periodic idiopathic shedding of the nail beginning at its proximal end. The temporary arrest of the function of the nail matrix may cause onychomadesis. Neurologic disorders, peritoneal dialysis, cutaneous T-cell lymphoma, Kawasaki's disease, pemphigus vulgaris, drug allergy, and keratosis punctata palmaris et plantaris have been reported causes. It may appear as a periodic finding in runners. Immobilization from casting for fractures may cause onychomadesis and pyogenic granuloma formation. Medications such as antineoplastic agents, azithromycin, and retinoids may cause onychomadesis also.

 


Beau's linesBeau's lines are transverse furrows that begin in the matrix and progress distally as the nail grows (Fig. 33-42). They are ascribed to the temporary arrest of function of the nail matrix. Although usually found to be bilateral, unilateral Beau's lines may occur. Various systemic and local traumatic factors may cause this. They may result from almost any systemic illness or major injury, such as a broken hip. Some specific associations are childbirth, measles, paronychia, acute febrile illnesses, high altitude exposure, and drug reaction. When the process is intermittent, the nail plate may resemble corduroy. Shelley “shoreline” nails appear to be a very severe expression of essentially the same transient growth arrest. They have been reported in all 20 nails of a newborn.

 


Half and half nailsHalf and half nails show the proximal portion of the nail white and the distal half red, pink, or brown, with a sharp line of demarcation between the two halves (Fig. 33-43). Seventy-six percent of hemodialysis patients and 56% of renal transplant patients have at least one type of nail abnormality. Half and half nails are the most frequent, affecting 20% of hemodialysis patients. Absence of lunula, splinter hemorrhage, and half and half nails were significantly more common in hemodialysis patients, while leukonychia was significantly more common in transplant patients.

 


Muehrcke's linesMuehrcke described narrow white transverse bands occurring in pairs as a sign of chronic hypoalbuminemia. The lines may resolve when serum albumin is raised to or near normal (Fig. 33-44). Unlike Mees’ lines, the disturbance appears to be in the nailbed, not in the nail plate. Similar lines have been reported in patients with normal albumin levels who are receiving chemotherapy. In a case of unilateral Muehrcke's lines associated with trauma, it was suggested that edema effects this change by inducing microscopic separation of the normally tightly adherent nail from its bed.

 


Mees’ linesMees described single or multiple white transverse bands in 1919 as a sign of inorganic arsenic poisoning. They have also been reported in thallium poisoning, septicemia, dissecting aortic aneurysm, parasitic infections, chemotherapy, and both acute and chronic renal failure.

 


Terry nailsIn Terry nails the distal 1–2 mm of the nail shows a normal pink color (Fig. 33-45), while the entire nail plate or proximal end has a white appearance as a result of telangiectases in the nailbed. These changes have been noted in 25% of hospitalized patients, most commonly those with cirrhosis, chronic congestive heart failure, and adult-onset diabetes, and in very elderly patients.

 


Onychorrhexis (brittle nails)Brittleness with breakage of the nails may result from frequent soap and water exposure, nail polish remover, hypothyroidism, anorexia or bulimia, or after oral retinoid therapy. It affects up to 20% of the population, women twice as often as men. Fragilitas unguium (nail fragility) is part of this process. In a series of 35 patients treated with biotin, 63% showed clinical improvement. The nail plate thickness in patients treated with biotin increases by 25%. Daily application of white petrolatum after soaking in water is also helpful.

 


OnychoschiziaSplitting of the distal nail plate into layers at the free edge (Fig. 33-46) is a very common problem among women and represents a dyshesion of the layers of keratin, possibly as a result of dehydration. Longitudinal splits may also occur. Patients with biotinidase deficiency may manifest onychoschizia, along with total or partial alopecia and an eczematous or desquamating periorificial eruption. Hypotonia, seizures, and developmental delay in children and depression in adults are the most common systemic abnormalities. Lack of treatment may result in loss of hearing and vision.

Nail polish should be discontinued; nail buffing can be substituted. Frequent application of emollients may be helpful. Biotin has also been shown to be effective in doses up to 2.5 mg/day, or 2–4 times that much in deficient patients.

 



Stippled nailsSmall, pinpoint depressions in an otherwise normal nail characterize this type of nail change. This may be an early change seen in psoriasis. Stippled nails are also seen with some cases of alopecia areata, in early lichen planus, psoriatic or rheumatoid arthritis, chronic eczematous dermatitis, perforating granuloma annulare, and in some individuals with no apparent disease. The deeper, broader pits are more specific for psoriasis. The pitting in alopecia areata tends to be shallower and more regular, suggesting a “Scotch plaid” (tartan) pattern.

 



Racquet nails (nail en raquette)In racquet nails, the end of the thumb is widened and flattened, the nail plate is flattened as well, and the distal phalanx is abnormally short (Fig. 33-47). Racquet nails occur on one or both thumbs and are apparently inherited as an autosomal-dominant trait.

 


Chevron nail (herringbone nail)This entity appears to be a rare transient fingernail ridge pattern of children. The ridges arise from the proximal nailfold and converge in a V-shaped pattern toward a midpoint distally.

 


HapalonychiaSoftened nails result from a defect in the matrix that makes the nails thin and soft so that they can be easily bent. This type of nail change is attributed to malnutrition and debility. It may be associated with myxedema, rheumatoid arthritis, anorexia, bulimia, Hansen's disease, Raynaud phenomenon, oral retinoid therapy, or radiodermatitis.

 


PlatonychiaThe nail is abnormally flat and broad. It may be seen as part of an autosomal-dominant condition in which multiple nail abnormalities are present in many members of a large family.

 


Nail–patella syndrome (hereditary osteo-onychodysplasia, Fong syndrome)Nail–patella syndrome comprises numerous anomalies and is characterized by the absence or hypoplasia of the patella and congenital nail dystrophy. Triangular lunulae are characteristic (Fig. 33-48). Other bone features are thickened scapulae, hyperextensible joints, radial head abnormalities, and posterior iliac horns. The skin changes may also include webbing of the elbows. Eye changes such as cataracts, glaucoma, and heterochromia of the iris may also be present. Hyperpigmentation of the pupillary margin of the iris (“Lester iris”) is a characteristic finding in about half the cases. Patients with nail–patella syndrome may exhibit glomerulonephritis with urinary findings of albuminuria, hematuria, and casts of all kinds, especially hyaline casts. They may be predisposed to developing hemolytic–uremic syndrome, edema, and hypertension. Sixty percent of patients have renal abnormalities, and 20% suffer from renal failure. It is an autosomal-dominant trait localized to the distal long arm of chromosome 9. Limb and kidney defects seen in L1M-homeodomain protein Lmx1b mutant mice are similar to those present in patients with nail–patella syndrome. Mutations of the human LMX1B gene result in this syndrome.

 


OnychophagiaNail biting is a common compulsive behavior that may markedly shorten the nail bed, sometimes damages the matrix, and at times leads to pterygium formation. It is a difficult habit to cure. If there is strong motivation, habit reversal training with awareness training, competing response training, and social support may help. Psychopharmacologic intervention with medications, such as serotonin-reuptake inhibitors, and hypnosis are other options.

 



OnychotillomaniaOnychotillomania is a compulsive neurosis in which the patient picks constantly at the nails or tries to tear them off. Like onychophagia, this obsessive–compulsive disorder may be treated by biofeedback, cognitive–behavioral methods, hypnosis, or psychopharmacologic agents.

 


OnycholysisOnycholysis is a spontaneous separation of the nail plate, usually beginning at the free margin and progressing proximally. Rarely, the lateral borders may be involved, with spread confined to these. Less often, separation may begin proximal to the free edge, in an oval area 2–6 mm broad, with a yellowish-brown hue (“oil spot”). This is a lesion of psoriasis; ordinary distal onycholysis is also commonly due to psoriasis. The nail itself is smooth and firm with no inflammatory reaction. Underneath the nail a discoloration may occur from the accumulation of bacteria, most commonly Pseudomonas, or yeast, most commonly Candida. Color changes, such as green (a result of pyocyanin from Pseudomonas), black, or blue may be seen. One or more nails may be affected.

Onycholysis is noted most commonly in women, probably secondary to traumatically induced separation. It is common in patients with hand dermatitis. Keratinization of the distal nailbed, chronic exposure to irritants, untreated dermatitis, and secondary infection with Candida albicans are potential reasons for the failure of the nail to reattach itself.

Systemic causes are many: hyper- and hypothyroidism, pregnancy, porphyria, pellagra, and syphilis. Onycholysis has also been associated with atopic dermatitis, eczema, lichen planus, congenital abnormalities of the nails, trauma induced by clawing, pinching, stabbing (manicuring), and foreign-body implantation. It may be caused by mycotic, pyogenic, or viral (herpes) infections. Women should be checked for vaginal candidiasis, because that anatomic location may be the source of the infection opportunistically invading and aggravating onycholysis. Chemical causes may include the use of solvents, nail polish base coat, nail hardeners containing formalin derivatives, artificial fingernails, and allergic or irritant contact dermatitis from their use. Rarely, photo-onycholysis may occur during or soon after therapy with tetracycline derivatives, psoralens, fluoroquinolones, or chloramphenicol, and subsequent exposure to sunlight. Chemotherapeutic agents and systemic retinoids may induce onycholysis. On rare occasions it may be a sign of subungual exostoses, squamous cell carcinoma, or metastasis. Autosomal-dominant hereditary forms are also known.

Trauma and chemical irritants should be completely avoided and the nailbed should be kept completely dry. The affected portion of the nail should be kept clipped away. Drying by exposing the nailbed in this way will rid the area of Pseudomonas and assist greatly in eliminating Candida. The combination of drying and topical steroids to minimize inflammation will often allow for reattachment of the nail and improvement or cure. Usually, this process takes 3–6 months or more to occur.

 


Median nail dystrophy (dystrophia unguis mediana canaliformis, solenonychia)Median nail dystrophy consists of longitudinal splitting or canal formation in the midline of the nail. The split, which often resembles a fir tree, occurs at the cuticle and proceeds outward as the nail grows (Fig. 33-49). Trauma has been suspected of being the chief cause. Repeated typing with the nail tip on personal digital assistants or Blackberry™-type devices has been reported to cause a median nail dystrophy. Some cases will resolve with avoidance of trauma; however, many will persist for years despite scrupulous care. The deformity may result from a papilloma or glomus tumor in the nail matrix, producing a structure like a tube (solenos) distal to it. Familial cases and an onset with isotretinoin therapy are other associations.

 


Pterygium unguisPterygium unguis forms as a result of scarring between the proximal nailfold and matrix. The classic causative example is lichen planus. It has been reported to occur as a result of sarcoidosis, porokeratosis of Mibelli, peripheral circulatory disturbances, and Hansen's disease. Onychomatricoma may uncommonly simulate pterygium, but histologic examination will confirm the nature of this benign tumor.

 



Pterygium inversum unguisPterygium inversum unguis is characterized by adherence of the distal portion of the nailbed to the ventral surface of the nail plate (Fig. 33-50). The condition may be present at birth or acquired, and may cause pain with manipulation of small objects, typing, and close manicuring of the nail. It is a condition resulting from the extension of the zone of the nailbed that normally contributes to the formation of the nail plate. This eventually leads to a more ventral and distal extension of the hyponychium. The most common forms of pterygium inversum unguis are the acquired secondary forms caused by systemic connective tissue diseases, particularly progressive systemic sclerosis and SLE.

 


HangnailHangnail is an overextension of the eponychium (cuticle), which becomes split and peels away from the proximal or lateral nailfold. These lesions are painful and annoying, so that persistent cuticle biting frequently develops. Trimming these away with scissors is the best solution. The use of emollient creams to keep the cuticle soft is also recommended.

 


Pincer nailsPincer nails, trumpet nails, or omega (from the shape of the Greek letter) nails are alternative terms for a common toenail disorder in which the lateral edges of the nail slowly approach one another, compressing the nailbed and underlying dermis (Fig. 33-51). It may less often occur in the fingernails and, surprisingly, is usually asymptomatic. Uncommonly, pain, recurrent or chronic infections, or even underlying osteomyelitis may complicate this condition. It may be an autosomal-dominantly inherited condition, acquired after trauma, or associated with Kawasaki's disease, renal disease, lupus erythematosus or use of β-blockers.

Some treatment success has been obtained with the use of commercial plastic braces after flattening of the nail. Urea ointment under occlusion, various surgical approaches, or chemical matricectomy with phenol and surgical nailbed repair have also been reported to be effective.

 


Onychocryptosis (unguis incarnatus, ingrown nail)Ingrown toenail is one of the most frequent nail complaints. It occurs chiefly on the great toes, where there is an excessive lateral nail growth into the nailfold, leading to this painful, inflammatory condition. The lateral margin of the nail acts as a foreign body and may cause exuberant granulation tissue. Unguis incarnatus may be caused by wearing improperly fitting shoes and by improper trimming of the nail at the lateral edges so that the anterior portion cuts into the flesh as it grows distally. Drugs such as isotretinoin, lamivudine, and indinavir may induce periungual granulation tissue mimicking onychocryptosis.

In mild cases, soaking the foot in warm soapy water and insertion of a cotton pad, dental floss, or a flexible plastic tube beneath the distal corner of the offending nail may make surgery unnecessary. When surgical intervention is necessary, simple removal of the lateral portion of the nail plate can produce significant relief. Another simple operation involves removal of the overhanging lateral nailfold so that the nail does not cut into it. When healed, the nail edge resembles that of the thumb, and an excellent functional result occurs. The nail is not altered, since it is not touched.

Partial or complete nail avulsion with ablation of the nail matrix will prevent recurrence. Ablation can be accomplished surgically, with phenol, 10% sodium hydroxide, or with a CO2 laser. When phenol is used, the proximal nailfold should be incised and reflected to avoid burning the nailfold. As an alternative, it can be left in place and injected with a corticosteroid to reduce the subsequent inflammation. Liquid nitrogen spray to the area of tissue and nail involved for a freeze time of 20–30 s has been successful in some patients, but may be painful and is reserved for patients in whom other surgical approaches are not appropriate.

 



RetronychiaRetronychia is an unusual event associated with ingrowing of the nail plate into the proximal nail fold. It then induces a chronic paronychia. The cause in the few cases reported has been trauma, usually of the great toe. An incomplete shedding of the nail plate results in the new growing nail pushing the old partially detached nail plate up and backwards into the proximal nail fold. Avulsion is curative.

 


Leukonychia or white nailsFour forms of white nail are recognized: leukonychia punctata, leukonychia striata, leukonychia partialis, and leukonychia totalis. The punctate (Fig. 33-52) variety is common in completely normal persons with otherwise normal nails. Leukonychia striata, transverse white parallel line, may be hereditary, of traumatic origin, or associated with systemic diseases such as HIV or Kawasaki's, or with drugs such as those used in chemotherapy. Partial leukonychia may occur with tuberculosis, nephritis, complex regional pain syndrome, Hodgkin disease, chilblains, metastatic carcinoma, or Hansen's disease, or be idiopathic.

Leukonychia totalis may be hereditary and is of a simple autosomal-dominant type. It may also be associated with typhoid fever, Hansen's disease, cirrhosis, ulcerative colitis, nail biting, use of emetine, complex regional pain syndrome, cytostatic agents, and trichinosis. Leukonychia may result from abnormal keratinization, with persistence of keratohyalin granules in the nail plate.

A syndrome comprising leukonychia totalis, multiple sebaceous cysts, and renal calculi in several generations has been reported. Other reports have linked total leukonychia with deafness or with koilonychia; however, it is most often inherited as an isolated finding.

 


Longitudinal erythronychiaLongitudinal red bands in the nail plate that commence in the matrix and extend to the point of separation of the nail plate and nailbed may occur on multiple nails with inflammatory conditions such as lichen planus or Darier's disease, or as an isolated finding. When only a localized single or bifid streak is present, this may signal a benign or malignant tumor of the matrix. The fingernails of middle-aged persons are most commonly affected, with the thumbnail being most frequently involved. There may be a distal keratosis seen, as with Darier, human papilloma virus (HPV) infection, or a squamous cell carcinoma. Excision of this distal keratosis, however, usually does not result in cure or diagnostic findings; biopsy of the affected matrix is necessary. Since this may lead to a scar with a permanent split of the nail plate, observation may be indicated. As in longitudinal melanonychia, if the band broadens over time, then an excisional biopsy is indicated, as this may be secondary to an amelanotic melanoma.

 


MelanonychiaBlack or brown pigmentation of the normal nail plate is termed melanonychia. It may be present as a normal finding on many digits in black patients, as a result of trauma, systemic disease, or medication, or as a postinflammatory event from such localized events as lichen planus or fixed drug reaction. Pigmentation of the nails may occur with acanthosis nigricans, Addison's disease, Peutz–Jeghers syndrome, and vitamin B12 deficiency, after adrenalectomy for Cushing syndrome, as a part of Laugier–Hunziker syndrome (pigmentation of the nails associated with buccal and lip hyperpigmentation), with PUVA or ionizing radiation treatment, and as a drug-induced melanocyte activation with such medications as chemotherapy, antimalarials, minocycline, antivirals (zidovudine [Fig. 33-53] or lamivudine), or metals (gold, arsenic, thallium, or mercury). Drugs may induce both transverse and longitudinal bands, with multidrug chemotherapy causing the majority of the former. Friction may cause longitudinal pigmented bands in the toenails, and subungual hemorrhage or black nail caused by Proteus mirabilis or Trichophyton rubrum may enter into the differential diagnosis of a dark nail.

Longitudinal black or brown banding of the nails has been reported to occur in 77–96% of black persons and 11% of Asians. It is a rare finding in white children; however, it is not uncommon in white adults. In a series by Duhard, the prevalence of melanonychia was 12.6 in 100 in a white hospitalized population, and 1.4 in 100 in 4400 white clinic-based patients. The risk increased with age, the peak occurring between the ages of 56 and 65.

When only one nail is affected by melanonychia striata (a single longitudinal band of brown or black color [Fig. 33-54]), a tumor of the nail matrix is the most important consideration. The location in the matrix can be inferred from the location of the pigment in the nail plate when viewed end-on. Dorsal nail-plate pigmentation results from a proximal matrix lesion. Ventral nail-plate pigmentation is the result of a lesion in the distal matrix.

Tosti et al studied 100 white adult patients with a single band of longitudinal melanonychia of unknown cause. Biopsies revealed melanocytic hyperplasia in 65, nevi in 22, melanocytic activation in 8, and melanoma in 5. Whereas they were unable to ascertain any clear clinical criteria that would exclude melanoma, they recommended a biopsy of any adult with the appearance of a longitudinal band of pigment in only one nail without a clear relation to a definite cause. Other reasons to biopsy include a band that has a triangular shape (one that is wider at the proximal part compared with the distal part), a blurred lateral border of the band, a lack of homogeneity of the pigmentations (bands or lines of different color), or pigmentation of the periungual skin (Hutchinson's sign). The latter is not pathognomonic, however, as Bowen's disease may produce this appearance, and pigmentation of the nail matrix and proximal nailbed may reflect through the nailfold (pseudo-Hutchinson's sign). Finally, dermoscopic features that suggest melanoma are a brown coloration of the background and the presence of irregular coloration, spacing, or thickness of longitudinal lines or disruption of their parallelism. Retracting the proximal nailfold to expose the origin of the streak at the matrix allows selection of the best biopsy site. The recommended biopsy is one that includes the whole lesion; this may be accomplished by the tangential matrix excision, which may leave minimal scarring in some cases, or more certainly this is accomplished by longitudinal excision.

Recommendations for prepubertal children, however, are different. Longitudinal melanonychia that appears in children is usually benign in nature, and it is recommended that since an ungual melanocytic band can appear at an age when other nevi appear, the majority can be followed. If the lesion is alarming in its appearance, especially if it is widening or darkening, sampling the whole lesion via tangential matrix or longitudinal excision is, however, necessary.

 


Green nailsWhen onycholysis is present, a green discoloration may occur in the onycholytic area as a result of an infection with Pseudomonas aeruginosa (see  Chapter 14). The color change may also occur as transverse green stripes. The stripes are ascribed to intermittent episodes of infection. Green nails may also result from copper in tap water.

 


Staining of the nail plateNicotine, dyes (including hair dyes and nail polish), potassium permanganate, mercury compounds, hydroquinone, elemental iron, mepacrine, photographic developer, anthralin, chrysarobin, glutaraldehyde, or resorcin may cause nail-plate staining. This is only a partial list; a complete listing is given in the article by Jeanmougin et al. A helpful diagnostic maneuver to distinguish nail-plate staining from exogenous sources and nail-plate pigmentation from melanin or endogenous chemicals is to scrape the surface of the nail plate several times firmly with a glass slide or scalpel blade. Exogenous stains frequently scrape off completely if the agent has not penetrated the entire nail plate. If the stain follows the curvature of the lunulae, it is probably endogenous; if it follows the curvature of the proximal and lateral nailfolds, it is exogenous.

 


Red lunulaeDusky erythema confined to the lunulae has been reported in association with alopecia areata. Twenty percent of patients with SLE have been reported to have this abnormality. It may also be seen in patients on oral prednisone for severe rheumatoid arthritis or dermatomyositis, in cardiac failure, cirrhosis, lymphogranuloma venereum, psoriasis, vitiligo, chronic urticaria, lichen sclerosus et atrophicus, CO2 poisoning, chronic obstructive pulmonary disease, twenty-nail dystrophy, and reticulosarcoma. The cause may be vascular congestion.

 


Spotted lunulaeThis distinctive change occurs with alopecia areata.

 


Purpura of the nail bedsPurpura beneath the nails usually results from trauma. Causes of toe involvement include physical pressure on the toes, such as that seen in surfboarding caused by a windsurfer trying to maintain his/her balance, or exogenous pressure exerted from poorly fitting shoes. It may simulate a melanoma if the patient does not communicate the acuteness at onset.

 


Blue nailsA blue discoloration of the lunulae is seen in argyria and cases of hepatolenticular degeneration (Wilson's disease). The blue color in the latter is probably related to the changes in copper metabolism by the patient. It has also been reported in hemoglobin M disease and hereditary acrolabial telangiectases. Lunular blue color, as well as blue discoloration of the whole nailbed, occurs with some therapeutic agents, especially 5-FU, minocycline, imipramine, mepacrine and other antimalarials, hydroxyurea, phenolphthalein, and azidothymidine. Blue discoloration may also result from subungual hematoma, blue nevi, and melanotic whitlow. Blue nails are a normal variant finding in Black people.

 


Yellow nail syndromeThe yellow nail syndrome is characterized by marked thickening and yellow to yellowish-green discoloration of the nails often associated with systemic disease, most commonly lymphedema and compromised respiration. The nails are typically overcurved both transversely and longitudinally, grow very slowly (less than 0.2 mm/week), are often subject to onycholysis, and lose both lunulae and cuticles (Fig. 33-55). Lymphedema, pleural effusions, chronic pulmonary infections, and chronic sinusitis most commonly precede the nail changes. Other less frequently associated conditions include autoimmune disorders, immunodeficiency states, the use of gold or d-penicillamine, and malignancies. In the latter cases, treatment of the underlying lymphoma or solid tissue tumor has resulted in improvement of the nail findings. Individual clinical responses have been seen with oral zinc or 800 IU/day of d-α-tocopherol alone or in combination with itraconazole. While approximately 30–50% of patients experience spontaneous improvement in the condition of their nails, fluconazole taken in combination with vitamin E cured or improved all 13 patients treated by Baran et al.

 


Neoplasms of the nailbedVarious benign and malignant neoplasms may occur in or overlying the nail matrix and in the nailbed. Signs heralding such neoplasms are paronychia, ingrown nail, onycholysis, pyogenic granuloma, nail-plate dystrophy, longitudinal erythronychia, bleeding, and discolorations. Symptoms of pain, itching, and throbbing may also occur with various neoplasms.

Benign tumors of the nails include verruca, pyogenic granuloma, fibromas, nevus cell nevi, myxoid cysts, angiofibromas (Koenen tumors), onychopapillomas, and epidermoid cysts. Pyogenic granuloma-like lesions may occur during treatment with isotretinoin, lamivudine, indinavir, or the epidermal growth factor receptor inhibitor family of drugs. Glomangioma is readily recognized by exquisite tenderness in the nailbed. Enchondroma of the distal phalanx often presents as a paronychia. Subungual exostoses may also present as an inflammatory process, but more commonly resemble a verruca at the start. Most of these are on the great toe, and radiographic evaluation will aid in the diagnosis of these last two entities. Onychopapillomas are benign tumors of the nail bed which usually present as longitudinal erythronychia. Tender swelling of the distal finger with nail distortion and radiographic evidence of solitary lytic changes can be caused by intraosseous epidermoid cysts.

Onychomatricoma is a benign tumor of the nail matrix. It presents as a yellow thickened plate growing out from under the proximal nailfold and then extending distally in a longitudinal band (Fig. 33-56). There is an increased transverse curvature of the nail and splinter hemorrhages often are seen in the proximal nail. Uncommonly, it can appear as a cutaneous horn emanating from the proximal nailfold, with dorsal pterygium formation. Biopsy at the matrix origin will permit diagnosis.

Bowen's disease and squamous cell carcinoma of the nailbed are uncommon. Radiographs may reveal lytic changes in the distal phalanx. Metastases are rare. Mohs surgery is the treatment of choice. When they occur on more than one digit, they are proven to be secondary to HPV infection. Bowen's disease may be pigmental (Fig. 33-57). When keratoacanthoma occurs, there is often lysis of underlying bone, which fills in after excision of the tumor. Basal cell carcinoma may occur, but is uncommon in this location.

Subungual melanoma (Fig. 33-58) is frequently diagnosed late in the course of growth, since it simulates onychomycosis or subungual hematoma, with which it is confused. Amelanotic melanoma may occur and may be mistaken for granuloma pyogenicum. Although melanoma is rare among Japanese, periungual and subungual melanoma is more frequently found in Japanese than in other ethnic populations. Discussion of melanoma in this location may be found in  Chapter 30 and in the melanonychia section of this chapter.

Onycholemmal carcinoma is a slowly growing malignant tumor of the nail bed epithelium. It is composed of small cysts filled with eosinophilic amorphous keratin. The cyst wall is lined with atypical keratinocytes. No granular layer is seen. Also solid nests and strands of atypical keratinocytes fill the dermis and may invade the bone. Mohs excision or even disarticulation of the digit may be necessary.

Evaluation of these masses may be carried out by plain x-ray, looking for bone lysis or other changes. MRI by both T1-weighted spin-echo images and turbo spin-echo T2-weighted images may offer excellent diagnostic information about these tumors as well.

 





 

 

33.8Disorders of sweat gland

Posted by Dr.Md.Hadiuzzaman on February 11, 2013 at 11:00 PM Comments comments (0)

Disorders of the sweat glandsHyperhidrosisHyperhidrosis, or excessive sweating, may be localized to one or several areas or it may be more generalized. True generalized hyperhidrosis is rare, and even hyperhidrosis caused by systemic diseases is usually accentuated in certain regions.

Palmoplantar hyperhidrosis (emotional hyperhidrosis)This type of hyperhidrosis is usually localized to the palms, soles, and/or axillae, and may be worse during warm temperatures. Patients with palm and sole hyperhidrosis may also have axillary hyperhidrosis, but only 25% of patients with axillary hyperhidrosis have palmoplantar hyperhidrosis. The hands may be cold and show a dusky hue. The soggy keratin of the hyperhidrotic soles is frequently affected by pitted keratolysis and has a foul odor. Sweating may be intermittent; in these cases anxiety, stress, or fear may trigger it. When sweating is constant, usually emotion is not as important.

This type of sweating can be autosomal-dominantly inherited. Its onset is in childhood for the palmar type and adolescence for axillary disease. It tends to improve with age. Sweating typically ceases during sleep.

Gustatory hyperhidrosisCertain individuals regularly experience excessive sweating of the forehead, scalp, upper lip, perioral region, or sternum a few moments after eating spicy foods, tomato sauce, chocolate, coffee, tea, or hot soups. Gustatory sweating may be idiopathic or caused by hyperactivity of the sympathetic nerves (Pancoast tumor or postoperatively), sensory neuropathy (diabetes mellitus or subsequent to zoster), parotitis or parotid abscess, and surgery or injury of the parotid gland (auriculotemporal syndrome of von Frey). Frey syndrome occurs in one-third or more of patients following parotid surgery. Fortunately, only 10% of affected patients require treatment.

Other localized forms of hyperhidrosisLocalized sweating can occur over lesions of blue rubber bleb nevus, glomus tumors, and hemangiomas (sudoriferous hemangioma), and in POEMS syndrome, Gopalan syndrome, complex regional pain syndrome, as a result of spinal cord tumors (especially when unilateral palmar hyperhidrosis is the complaint), and pachydermoperiostosis.

Generalized hyperhidrosisFebrile diseases, vigorous exercise, or a hot, humid environment, such as a tropical milieu, may induce generalized hyperhidrosis. Hyperthyroidism, acromegaly, diabetes mellitus, pheochromocytoma, hypoglycemia, salicylism, substance abuse, lymphoma, carcinoid syndrome, pregnancy, and menopause may also produce generalized hyperhidrosis. Additional causes of hyperhidrosis include concussion, Parkinson's disease, other disturbances of the sympathetic nervous system, and metastatic tumors producing a complete transection of the spinal cord. Drugs such as anticholinesterases, antidepressants of the selective serotonin-reuptake inhibitor or tricyclic types, antiglaucoma agents, bladder stimulants, opioids, and sialogogs may cause hyperhidrosis.

TreatmentThe therapy of generalized hyperhidrosis is aimed at treating the underlying systemic disease. Virtually all cases of hyperhidrosis seen by dermatologists are of the palmoplantar or axillary types, and the treatments discussed below relate primarily to these conditions.

Topical medicationTopical aluminum chloride or aluminum chlorhydroxide are the most commonly used agents for hyperhidrosis. For the axillae, application of a 10–35% solution nightly to a very dry axilla (blown dry with a hair dryer) is usually very effective. To limit irritation, lower concentrations should be tried first. Also, it should be washed off in 6–8 h. Occlusion is usually not required. In palmar hyperhidrosis the application of aluminum chloride nightly in up to a 50% concentration, alone or occluded with plastic gloves, has produced good results for some patients. If topical treatment is effective when performed nightly, the frequency may be reduced to as little as once or twice a week with continued benefit.

IontophoresisIontophoresis with plain tap water is an alternative for patients for whom topical treatments fail. It is frequently effective, using either a Drionic device or a Fischer unit. Treatments generally require 20–30 min sessions each day or twice a day. Once response has occurred, treatments may be used intermittently (as little as once every 2 weeks) for maintenance. Use of glycopyrrolate 0.01% and aluminum chloride 2% in the iontophoresis medium may hasten the response. A new dry-type iontophoresis has been described but is not readily available.

Botulinum toxinInjection of botulinum A toxin into 4 cm2 areas on the palms, soles, or axillae dramatically reduces sweating at the treated areas to at least 25% and often to less than 10% of baseline rates. Dosages vary according to the type of botulinum toxin A and the site of treatment. Grunfeld et al offer a complete review of injection techniques and tips. Complications are rare but include some grip weakness when higher doses are used in the palms. This problem, the expense, and the painful injections limit its use in the palms and soles especially. The hypohidrosis continues for an average of 7 months, with some patients continuing to have substantial benefit at 16 months after one injection. Repeated injections generally do not lose efficacy and result in similar response and complication rates. This form of treatment should be offered to all patients who fail topical treatments before surgical modalities are considered. Frey syndrome remits for 1–1.5 years in nearly every patient treated. This treatment may be considered for other rare forms of localized hyperhidrosis. Myobloc (botulinum toxin B) is also effective, but with more limited duration of response.

Internal medicationThe use of anticholinergic agents such as propantheline bromide, oxybutynin (available in an extended-release formulation which may result in lower efficacy), and glycopyrrolate may be helpful. The dosage of each is regulated by the patient's tolerance and response. Often, sweating is suppressed just as anticholinergic side effects reach intolerable levels, and this approach has to be abandoned. Side effects of acetylcholine-blocking agents may also cause or aggravate such conditions as glaucoma and convulsions. The effects on sweating generally last 4–6 h, and many patients prefer to use the medication to ensure dryness for special occasions only, rather than as continuous treatment. Other agents reported to reduce localized hyperhidrosis include diltiazem and clonidine.

Surgical treatmentAxillary hyperhidrosis may be effectively controlled by excision of the most actively sweating portion of the axillary skin, followed by undercutting and subcutaneous resection of the sweat glands for 1–2 cm on each side of the elliptical excision. This procedure is virtually always effective. Alternatively, liposuction or surgical ultrasonic aspiration removal may be used. The most important preoperative consideration is the accurate mapping of the most active sweating areas of the axillae. The responsible eccrine glands are not necessarily located in the same areas as the axillary hair and are often in a reasonably limited area. Mapping may be performed with cobalt chloride or starch iodide.

Upper thoracic sympathectomy has been found to be effective in excessive palmar sweating when all other measures have failed. Sympathetic denervation of the upper extremities is performed via endoscopy by reversibly clipping or performing resection of the fourth thoracic sympathetic ganglion. Acute surgical complications occur in less than 2% but include chronic pain, infection, pneumothorax, hemothorax, bleeding, pneumonia, and even death. Sweating of the hands is stopped completely. Only 60% of patients are satisfied, however, since compensatory and gustatory hyperhidrosis occurs in more than two-thirds of patients. This may be severe and as debilitating as the original problem. Topical glycopyrrolate may sometimes help alleviate compensatory hyperhidrosis, but it does not decrease with time. Horner syndrome may rarely result. Endoscopic thoracic sympathetic block at T4 is being evaluated as another alternative.


Anhidrosis (hypohidrosis)Anhidrosis is the absence of sweating. Hypohidrosis, or reduced sweating, is part of the spectrum of these disorders. Dysfunction in any step in the normal physiologic process of sweating can lead to decreased or absent sweating. It may be localized or generalized. Generalized anhidrosis occurs in anhidrotic ectodermal dysplasia, miliaria profunda (tropical asthenia), Sjögren syndrome, Fabry syndrome, hereditary sensory neuropathy (type IV) with anhidrosis, and in some patients with diabetic neuropathy, thyroid dysfunction, and multiple myeloma. A large number of drugs may cause hypohidrosis. These include anticholinergics, antidepressants of the tricyclic type, antiepileptics, antihistamines, antihypertensives, antipsychotics, antiemetics, antivertigo drugs, bladder antispasmodics, gastric antisecretory drugs, muscle relaxants, neuromuscular paralytics, and opioids. Anhidrosis may follow infections, be part of a neurodegenerative disorder, occur as a symptom related to toxin exposure, be a paraneoplastic phenomenon, or be secondary to autoimmune inflammation. Atopic dermatitis is frequently associated with reduced sweating and pruritus when sweating is triggered. Patients with psoriasis may have similar symptoms, but less frequently.

Anhidrosis with pruritus is a rare syndrome of young adults. Severe itching occurs whenever they are stimulated to sweat. No sweat is delivered to the skin surface, but when the body temperature is raised by about 0.5°C, fine papules appear at each eccrine orifice. The associated pruritus is so severe that patients feel completely incapacitated and distracted. Cooling immediately resolves the symptoms. This may represent one form of tropical asthenia or a mild form of the autonomic neuropathies described below. The natural history is unknown, but spontaneous resolution may occur after several years. These patients are frequently misdiagnosed as having cholinergic urticaria.

Segmental anhidrosis may be associated with tonic pupils (Holmes–Adie syndrome); this is called Ross syndrome. Patients have heat intolerance and segmental areas of anhidrosis on the trunk, arms, or legs. Loss of deep tendon reflexes in the arms, trunk, and legs is consistently seen. Compensatory segmental hyperhidrosis of functionally intact areas may occur. A selective degeneration of the cholinergic sudomotor neurons is the hypothesized abnormality.

Autonomic neuropathies associated with antibodies to nicotinic acetylcholine receptors may cause a variety of symptoms related to dysfunction of systems controlled by autonomic nerves. There is a spectrum of abnormalities ranging from severe autonomic failure characterized by orthostatic hypotension, gastrointestinal dysmotility, anhidrosis, bladder dysfunction, and sicca syndrome to isolated anhidrosis and heat intolerance. In this condition a biopsy may reveal an inflammatory infiltrate surrounding the eccrine glands, and some patients respond to pulse steroids or immunosuppressants. It may also spontaneously resolve.

Anhidrosis localized to skin lesions occurs regularly over plaques of tuberculoid leprosy. This is also true of segmental vitiligo (but not generalized type), in the hypopigmented streaks of incontinentia pigmenti, in lesions of syringolymphoid hyperplasia with alopecia and anhidrosis, and on the face and neck of patients with the rare Bazex syndrome consisting of follicular atrophoderma, basal cell carcinomas, and hypotrichosis, an X-linked dominant disorder.

 



BromhidrosisAlso known as fetid sweat, osmidrosis and malodorous sweating, bromhidrosis is chiefly encountered in the axillae. Bacterial decomposition of apocrine sweat, producing fatty acids with distinctive offensive odors, is considered to be the cause. Often, patients who complain of offensive axillary sweat actually have no offensive odor; the complaint represents a delusion, paranoia, phobia, or a lesion of the central nervous system. Intranasal foreign body and chronic mycotic infection in the sinuses are additional causes. True bromhidrosis is usually not recognized by the patient.

Fish odor syndrome should be considered in patients presenting with complaints of offensive odor. It is caused by excretion of trimethylamine (which smells like rotten fish) in the eccrine sweat, urine, saliva, and other secretions. This chemical is produced from carnitine and choline in the diet and is normally metabolized in the liver. An autosomal-dominant defect in the ability to metabolize trimethylamine because of a defect in flavin-containing mono-oxygenase 3 is the cause of this syndrome. Dietary reduction of foods high in carnitine and choline is beneficial.

Antibacterial soaps and many commercial deodorants are quite effective in controlling axillary malodor. Frequent bathing, changing of underclothes, shaving of the axillae, and topical application of aluminum chloride (Drysol) are all helpful measures. Surgical removal of the glands either by excision or tumescent liposuction is possible, as in axillary hyperhidrosis, but this is rarely indicated. Botulinum toxin A injections in the axilla have controlled body odor in this site as well in the pubic area.

Plantar bromhidrosis is produced by bacterial action on eccrine sweat-macerated stratum corneum. Hyperhidrosis is the chief associated factor, and pitted keratolysis is often present. Careful washing with an antibacterial soap and the use of dusting powders on the feet are helpful in eliminating bromhidrosis. Use of topical antibiotics, such as clindamycin, may be beneficial. Previously described measures to control plantar hyperhidrosis should be instituted. Botulinum toxin A is likely to be effective.

 



ChromhidrosisChromhidrosis, or colored sweat, is an exceedingly rare functional disorder of the apocrine sweat glands, frequently localized to the face or axilla. It has been less often noted on the abdomen, chest, breasts, thighs, groin, genitalia, and lower eyelids. The colored sweat may be yellow (most common), blue, green, or black. The colored secretion appears in response to adrenergic stimuli, which cause myoepithelial contractions. Colored apocrine sweat fluoresces and is caused by lipofuscin. Treatment with botulinum toxin A or topical capsaicin has been reported to be effective.

Eccrine chromhidrosis is caused by the coloring of the clear eccrine sweat by dyes, pigments, or metals on the skin surface. Examples are the blue–green sweat seen in copper workers and the “red sweat” seen in flight attendants from the red dye in the labels in life-vests. Brownish staining of the axillae and undershirt may occur in ochronosis. Bile secretion in eccrine sweat occurs in patients with liver failure and marked hyperbilirubinemia. Small, round, brown or deep-green macules occur on the palms and soles.

 



Fox–Fordyce diseaseFox–Fordyce disease is rare, occurring mostly in women during adolescence or soon afterward. It may occasionally be familial in nature. It is characterized by conical, flesh-colored or grayish, intensely pruritic, discrete follicular papules in areas where apocrine glands occur. The axillae and areolae are the primary sites of involvement, but the umbilicus, pubes, labia majora, and perineum may be affected. Apocrine sweating does not occur in affected areas, and hair density may be decreased. In some cases there is no itching. Ninety percent of cases occur in women between the ages of 13 and 35, but the disease may present postmenopausally or in males. Pregnancy invariably leads to improvement.

Histologically, Fox–Fordyce disease is characterized by obstruction of the follicular ostia by orthokeratotic cells. An inflammatory infiltrate of lymphocytes surrounds the upper third of the hair follicles and upper dermal vessels. There is an associated spongiosis of the infundibulum at the site of entrance of the apocrine duct into the hair follicle. In one case, detached apoeccrine cells obstructed the duct. Foam cells have been noted to be a histologic marker, as many of the above findings are either nonspecific or difficult to demonstrate. Localized axillary xanthomatosis has been postulated to be either a variant of Fox–Fordyce disease or a type of verruciform xanthoma.

No form of therapy is universally effective for Fox–Fordyce disease. Oral contraceptive pills, topical tretinoin or adapalene, topical pimecrolimus or weak corticosteroid creams, intralesional steroids, topical clindamycin solution, benzoyl peroxide, isotretinoin, and UV phototherapy have all been effective in small numbers of patients. Excision or liposuction-assisted curettage may be successful in axillary sites.

 



Granulosis rubra nasiGranulosis rubra nasi is a rare familial disease of children, occurring on the nose, cheeks, and chin. It is characterized by diffuse redness, persistent hyperhidrosis, and small dark red papules that disappear on diascopic pressure. The tip of the nose is red or violet. There may be a few small pustules. Hyperhidrosis precedes the erythema (Fig. 33-37). The tip of the nose is cold and is not infiltrated. The disease disappears spontaneously at puberty without leaving any traces. The cause is unknown. Histologically, blood vessels are dilated and there is an inflammatory infiltrate about the sweat ducts.

Treatment is with local preparations for relief of the inflammation, and reassurance that with puberty there is usually involution of the process.

 


HidradenitisHidradenitis is a term used to describe diseases in which the histologic abnormality is primarily an inflammatory infiltrate around the eccrine glands. This group includes neutrophilic eccrine hidradenitis and idiopathic plantar hidradenitis (recurrent palmoplantar hidradenitis).

Neutrophilic eccrine hidradenitisNinety percent of patients with neutrophilic eccrine hidradenitis (NEH) have a malignancy. It has been described primarily in patients with acute myelogenous leukemia (AML); however, other leukemias, lymphomas, and uncommonly solid tumors may be present. It usually begins about 10 days after the start of chemotherapy. While the majority of patients have been treated with cytarabine, it has not been uniformly linked to any chemotherapeutic agent and may occur in patients who have not been treated. Patients with AML in remission have been reported to develop NEH with associated sclerodermoid changes that herald a relapse of the leukemia. Granulocyte colony-stimulating factor (G-CSF), imatinib mesylate, zidovudine, acetaminophen, and various antibiotics have also been implicated as triggers for this neutrophilic dermatosis.

The lesions are typically erythematous and edematous papules and plaques of the extremities, trunk, face (periorbital), and palms (in decreasing frequency). Pigmentation, purpura, or pustules may be present within the papules and plaques. Fever and neutropenia are often present. Histologically, there is a dense neutrophilic infiltrate around and infiltrating eccrine glands. Necrosis of sweat glands may be present, with or without the inflammatory infiltrate. Syringosquamous metaplasia may occur. This finding can also occur in fibrosing alopecia, in burn scars, adjacent to various nonmelanoma skin cancers and ischemic and surgical ulcers, in alopecia mucinosa, and in ports of radiation therapy.

The lesions may recur with repeated courses of chemotherapy, but many do not. Resolution over 1–4 weeks (average, 10 days) usually occurs. Nonsteroidal anti-inflammatory drugs or oral corticosteroids may hasten the healing. Prophylactic administration of dapsone prevented recurrence in one patient.

Infectious neutrophilic hidradenitis may present as a recurrent, pruritic, papular eruption. Serratia, Enterobacter cloacae, Nocardia, and Staphylococcus aureus have been implicated, and appropriate antibiotics for bacterial agents are curative. The diagnosis is confirmed by histologic evaluation and culture of affected tissue (surface cultures may not be adequate). Additionally, many HIV-infected patients have developed neutrophilic eccrine hidradenitis.

Recurrent palmoplantar hidradenitisRecurrent palmoplantar hidradenitis is primarily a disorder of healthy children and young adults. Lesions are primarily painful, subcutaneous nodules on the plantar surface, resembling erythema nodosum. Rarely, palmar lesions also occur. In some children Pseudomonas infection may be the cause (pseudomonal hot foot, see  Chapter 14). Children may present refusing to walk because of plantar pain. The condition is typically recurrent, and may be triggered by exposure to wet shoes or cold, damp weather. The use of oral and topical steroidal preparations may be beneficial.

 



 

33.7 Diseases of skin apendages

Posted by Dr.Md.Hadiuzzaman on February 11, 2013 at 10:35 PM Comments comments (0)

Associated hair follicle diseasesPityriasis amiantacea (tinea amiantacea)Thick, asbestos-like (amiantaceous), shiny scales on the scalp characterize pityriasis amiantacea. The silvery-white or dull gray crusting may be localized or, less often, generalized over the entire scalp. The proximal parts of the hairs are matted together by the laminated crusts. There are no structural changes in the hair, but in some patches where the crusting is thick, there may be some purulent exudate under the crust and temporary alopecia such as occurs after some cases of furunculosis of the scalp.

The cause is most often severe or untreated seborrheic dermatitis or psoriasis. In a prospective study of 85 patients, psoriasis was documented in 35% and processes suggesting seborrheic dermatitis or atopic dermatitis occurred in another 35%. Tinea capitis was the eventual diagnosis in 13%. Staphylococcus was found in 96.5%, compared with 15% of controls. The patient should shampoo daily or every other day with selenium sulfide suspension, or a tar- or steroid-containing shampoo, for a couple of weeks. Prior application of peanut oil or a keratolytic a few hours before shampooing facilitates removal of the scales and crusts. With such debridement, followed by topical steroid solution in Caucasians or steroid ointment in African Americans, the secondary bacterial infection usually resolves without the need for oral antistaphylococcal therapy.


Folliculitis nares perforansPerforating folliculitis of the nose is characterized by small pustules near the tip of the inside of the nose. The lesion becomes crusted, and when the crust is removed it is found that the bulbous end of the affected vibrissa is embedded in the inspissated material. The affected hairs are typical of those occurring inside the nostril. Staphylococcus aureus may at times be cultured from the pustules. The hair should be removed and antibiotic ointment such as mupirocin applied.

 


Acquired perforating dermatosisPerforating folliculitis, Kyrle's disease, and acquired perforating collagenosis are designations that have been supplanted by the more inclusive term acquired perforating dermatosis. The condition is not uncommon and is most often associated with renal failure or diabetes or both. Between 4% and 10% of dialysis patients develop umbilicated dome-shaped papules on the legs, or less often on the trunk, neck, arms, or scalp, with variable itchiness (Fig. 33-35). Early lesions may be pustular; late lesions resemble prurigo nodularis both clinically and histologically. There is a central hyperkeratotic cone that projects into the dermis, so that when it is removed, a pitlike depression remains. Usually the papules are discrete, but they may coalesce to form circinate plaques. Coalescing verrucous plaques are frequently seen, especially on the lower extremities. Koebner phenomenon may also be observed, in which case plaques or elevated verrucous streaks are formed. The latter are seen primarily in the antecubital and popliteal spaces. Atrophic scars are seen on involution of these lesions.

Histologically, the epidermis becomes edematous, the granular layer disappears, and parakeratosis develops. Eventually, the epidermis becomes atrophic, with disruption of the sites over the papillae. Through these sites necrobiotic connective tissue, degenerating inflammatory cells, and collagen bundles are extruded into a cup-shaped epidermal depression.

The condition is felt to be a response to trauma, usually scratching or rubbing in response to the pruritus of the associated renal failure or dry skin. Other predisposing conditions reported include HIV infection, sclerosing cholangitis or other liver diseases, hypothyroidism, hyperparathyroidism, Hodgkin disease, in areas of healed herpes zoster, and as a reaction to laser hair removal or TNF-α inhibitors.

Ultraviolet treatment of either PUVA or UVB type helps the pruritus of renal disease and improves the perforating disorder. Hydration of the skin with a soaking tub bath in plain water, followed immediately (without drying) by triamcinolone ointment, is also useful. Topical retinoic acid (0.1% cream), allopurinol, doxycycline, isotretinoin, and etretinate have been effective in flattening lesions. HIV-infected patients may respond well to thalidomide. The disease may remit promptly after renal transplantation.

 


Reactive perforating collagenosisReactive perforating collagenosis is an inherited condition characterized by pinhead-sized, skin-colored papules that grow to a diameter of 4–6 mm and develop a central area of umbilication in which keratinous material is lodged (Fig. 33-36). The discrete papules may be numerous and involve sites of frequent trauma such as the backs of the hands, forearms, elbows, and knees. The lesion reaches a maximum size of about 6 mm in 4 weeks and then regresses spontaneously in 6–8 weeks.

It is believed that this is caused by a peculiar reaction of the skin to superficial trauma. Koebnerization is often observed. Young children are most frequently affected. Most reports support an autosomal-recessive mode of inheritance; however, a family in which it appeared to be inherited by autosomal dominance has been reported.

No specific treatment is indicated, since the lesions involute spontaneously. Tretinoin 0.1% cream may be effective.

 


Traumatic anserine folliculosisTraumatic anserine folliculosis is a curious gooseflesh-like follicular hyperkeratosis that may result from persistent pressure and lateral friction of one skin surface on another. Such friction is often caused by habitual pressure on the elbows, chin, jaw, or neck, often while watching television. Two-thirds of patients who develop this are atopic.

 


Erythromelanosis follicularis faciei et colliErythromelanosis follicularis faciei et colli is an erythematous pigmentary disease involving the follicles. A reddish-brown, sharply demarcated, symmetrical discoloration involves the preauricular and maxillary regions. At times the pigmentation may be blotchy. In addition, follicular papules and erythema are present. Under diascopic pressure the reddish-brown area, containing telangiectases, becomes pale and the light brown pigmentation becomes more apparent. Pityriasiform scaling and slight itching may occur. Keratosis pilaris on the arms and shoulders is frequently found. It preferentially affects Asian and Indian patients.

Histologically, a slight hyperkeratosis occurs, with epidermal hyperpigmentation and dilation of the upper dermal vessels. The hair follicles may be enlarged in the infundibular area and the sebaceous glands may be hypertrophic. A lymphocytic infiltration surrounds the adnexa.

 


Disseminate and recurrent infundibulofolliculitisHitch and Lund described a disseminate follicular eruption on the torso of a black man that involved all the pilosebaceous structures. The lesions were irregularly shaped papules pierced by a hair. They likened the eruption to cutis anserina viewed through a magnifying glass. The eruption is mildly pruritic at times, and is chronic, with recurrent exacerbations. The papules are uniform, and 1 or 2 mm in diameter; they involve all the follicles in the affected areas, which are usually the upper trunk and neck, though the entire trunk and proximal extremities may be involved. Rarely, pustules may occur.

Histologically, the infundibular portion of the follicles is chiefly affected, and the lesions are inflammatory rather than hyperkeratotic. Edema, lymphocytic and neutrophilic infiltration, and slight fibroblastic infiltration surround the affected follicles.

Treatment with topical steroids, isotretinoin, or PUVA may be effective.

 


Lichen spinulosusLichen spinulosus (keratosis spinulosa) is chiefly a disease of children and is characterized by minute filiform horny spines, which protrude from follicular openings independent of any papules. The spines are discrete and grouped. The lesions appear in crops and are symmetrically distributed over the trunk, limbs, and buttocks (acne corne). There is a predilection for the neck, buttocks, abdominal wall, popliteal spaces, and the extensor surfaces of the arms. Little or no itching is present. Occasional cases of a generalized form in adults with HIV infection or alcoholism have been reported.

Histologic evaluation shows simple inflammatory changes and follicular hyperkeratosis. The lesions may respond to keratolytics and emollients, such as salicylic acid, lactic acid, or urea gels or ointments. Tretinoin or tacalcitol creams are other alternatives. The lesions tend to involute at puberty.