Hypertrichosis

Hypertrichosis is rare in children and may be localized or generalized and permanent or transient. Hypertrichosis has many causes, some of which are listed in Table 654-1.

Table 654-1 CAUSES OF AND CONDITIONS ASSOCIATED WITH HYPERTRICHOSIS

INTRINSIC FACTORS

Racial and familial forms such as hairy ears, hairy elbows, intraphalangeal hair, or generalized hirsutism

EXTRINSIC FACTORS

Local trauma

Malnutrition

Anorexia nervosa

Long-standing inflammatory dermatoses

Drugs: Diazoxide, phenytoin, corticosteroids, Cortisporin, cyclosporine, androgens, anabolic agents, hexachlorobenzene, minoxidil, psoralens, penicillamine, streptomycin

HAMARTOMAS OR NEVI

Congenital pigmented nevocytic nevus, hair follicle nevus, Becker nevus, congenital smooth muscle hamartoma, fawn-tail nevus associated with diastematomyelia

ENDOCRINE DISORDERS

Virilizing ovarian tumors, Cushing syndrome, acromegaly, hyperthyroidism, hypothyroidism, congenital adrenal hyperplasia, adrenal tumors, gonadal dysgenesis, male pseudohermaphroditism, non–endocrine hormone–secreting tumors, polycystic ovary syndrome

CONGENITAL AND GENETIC DISORDERS

Hypertrichosis lanuginosa, mucopolysaccharidosis, leprechaunism, congenital generalized lipodystrophy, de Lange syndrome, trisomy 18, Rubinstein-Taybi syndrome, Bloom syndrome, congenital hemihypertrophy, gingival fibromatosis with hypertrichosis, Winchester syndrome, lipoatrophic diabetes (Lawrence-Seip syndrome), fetal hydantoin syndrome, fetal alcohol syndrome, congenital erythropoietic or variegate porphyria (sun-exposed areas), porphyria cutanea tarda (sun-exposed areas), Cowden syndrome, Seckel syndrome, Gorlin syndrome, partial trisomy 3q, Ambra syndrome

Hypotrichosis and Alopecia

Some of the disorders associated with hypotrichosis and alopecia are listed in Table 654-2. True alopecia is rarely congenital; it is more often related to an inflammatory dermatosis, mechanical factors, drug ingestion, infection, endocrinopathy, nutritional disturbance, or disturbance of the hair cycle. Any inflammatory condition of the scalp, such as atopic dermatitis or seborrheic dermatitis, if severe enough, may result in partial alopecia; hair growth returns to normal if the underlying condition is treated successfully, unless the hair follicle has been permanently damaged.

Table 654-2 DISORDERS ASSOCIATED WITH ALOPECIA AND HYPOTRICHOSIS

Congenital total alopecia: Atrichia with papules, Moynahan alopecia syndrome

Congenital localized alopecia: Aplasia cutis, triangular alopecia, sebaceous nevus

Hereditary hypotrichosis: Marie-Unna syndrome, hypotrichosis with juvenile macular dystrophy, hypotrichosis–Mari type, ichthyosis with hypotrichosis, cartilage-hair hypoplasia, Hallermann-Streiff syndrome, trichorhinophalangeal syndrome, ectodermal dysplasia “pure” hair and nail and other ectodermal dysplasias

Diffuse alopecia of endocrine origin: Hypopituitarism, hypothyroidism, hypoparathyroidism, hyperthyroidism

Alopecia of nutritional origin: Marasmus, kwashiorkor, iron deficiency, zinc deficiency (acrodermatitis enteropathica), gluten-sensitive enteropathy, essential fatty acid deficiency, biotinidase deficiency

Disturbances of the hair cycle: Telogen effluvium

Toxic alopecia: Anagen effluvium

Autoimmune alopecia: Alopecia areata

Traumatic alopecia: Traction alopecia, trichotillomania

Cicatricial alopecia: Lupus erythematosus, lichen planopilaris, pseudopelade, morphea (en coup de saber) dermatomyositis, infection (kerion, favus, tuberculosis, syphilis, folliculitis, leishmaniasis, herpes zoster, varicella), acne keloidalis, follicular mucinosis, sarcoidosis

Hair shaft abnormalities: Monilethrix, pili annulati, pili torti, trichorrhexis invaginata, trichorrhexis nodosa, woolly hair syndrome, Menkes disease, trichothiodystrophy, trichodento-osseous syndrome, uncombable hair syndrome (spun-glass hair, pili trianguli et canaliculi)

Hair loss in childhood should be divided into the following 4 categories: congenital diffuse, congenital localized, acquired diffuse, and acquired localized.

Acquired localized hair loss is the most common type of hair loss seen in childhood. Three conditions—traumatic alopecia, alopecia areata, tinea capitis—are predominantly seen (Tables 654-3 and 654-4).

Table 654-3 HELPFUL HISTORICAL CLUES IN DIAGNOSIS OF HAIR DISORDERS

Table 654-4 HELPFUL PHYSICAL EXAMINATION CLUES IN DIAGNOSIS OF HAIR DISORDERS

Traumatic Alopecia (Traction Alopecia, Hair Pulling, Trichotillomania)

Traction Alopecia

Traction alopecia is common and is seen in almost 20% of African American schoolgirls. It is due to trauma to hair follicles from tight braids or ponytails, headbands, rubber bands, curlers, or rollers (Fig. 654-1). There is a greater risk of traction alopecia if hair trauma is combined with chemically relaxed hair. Broken hairs and inflammatory follicular papules in circumscribed patches at the scalp margins are characteristic and may be subtended by regional lymphadenopathy. Children and parents must be encouraged to avoid devices that cause trauma to the hair and, if necessary, to alter the hairstyle. Otherwise, scarring of hair follicles may occur.