Three disorders of hair are shown in the images below. Identify each, and describe the pathophysiology & management.
(A) Alopecia areata
Alopecia areata is characterized by rapid hair loss in a sharply defined, usually round, zone. The specific cause is unknown. One theory is that AA may be an autoimmune disease mediated by T lymphocytes directed to hair follicles. Alopecia areata is a partial loss of scalp hair, alopecia totalis is 100% loss, and alopecia universalis is 100% loss of hair on the scalp and body. Exposed skin is usually smooth and white. Some patients complain of itching, tenderness, or a burning sensation before the patches appear, but others may be asymptomatic. Regrowth begins in 1 to 3 months and may be followed by loss in the same or other areas. The new hair is usually of the same color and texture, but it may be fine and white. Shallow pitting of nails is an associated condition. Most patients entirely regrow hair within 1 year without treatment; 10% develop chronic disease and may never regrow hair. Treatment includes intralesional glucocorticoids, minoxidil solutions, immunotherapy.
Trichomycosis is an infection of axillary or pubic hair caused by Corynebacterium. The hair shaft becomes coated with adherent yellow concretions. Hyperhidrosis is often present. Treatment includes shaving the hair, and controlling hyperhidrosis with antiperspirants. The infection itself can be treated with Naftin (Naftifine HCL 1 % cream).
Trichotillomania is a chronic impulse control disorder characterized by repetitive hair-pulling. Patient obtain feelings of pleasure, gratification, or relief from pulling out the hair. Prevalence ranges from 0.6% to 13%. It is commonly performed by young children, adolescents, and women. Hair is twisted around the finger and pulled or rubbed until extracted or broken. The affected area has an irregular angulated border, and the density of hair is greatly reduced; but the site is never bald, as in alopecia areata. Several short, broken hairs of varying lengths are usually randomly distributed. Patients benefit from psychiatric intervention. There is often concurrent anxiety or OCD.