Chapter 654 Disorders of Hair
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
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).
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.
Hair Pulling
Trichotillomania
Clinical Manifestations
Compulsive pulling, twisting, and breaking of hair produces irregular areas of incomplete hair loss, most often on the crown and in the occipital and parietal areas of the scalp. Occasionally, eyebrows, eyelashes, and body hair are traumatized. Some plaques of alopecia may have a linear outline. The hairs remaining within the areas of loss are of various lengths (Fig. 654-2) and are typically blunt-tipped because of breakage. The scalp usually appears normal, although hemorrhage, crusting (Fig. 654-3), and chronic folliculitis may also occur. Trichophagy, resulting in trichobezoars, may complicate this disorder.
