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AT-A-GLANCE
Alopecia areata is a nonscarring hair disorder.
It occurs in both genders equally and can affect every age group, although incidence at in younger age groups is higher.
It is the most common form of hair loss in children. Clinically, it presents with well-demarcated round or oval bald spots on the scalp or other parts of the body.
Of patients with alopecia areata, 5% develop hair loss of their entire scalp hair (alopecia areata totalis) and 1% develop alopecia areata universalis (loss of total body hair).
Nail changes include pitting or sandpaper nails.
Alopecia areata is thought to be an autoimmune disease with a possible hereditary component.
In general, alopecia areata is a medically friendly condition, but it can coexist with other autoimmune disorders such as Hashimoto thyroiditis and vitiligo.
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Alopecia areata is a common autoimmune hair disorder. This nonscarring, usually patchy hair loss condition can affect any hair-bearing area. At any given time, approximately 0.2% of the world population is suffering from alopecia areata. It has an estimated lifetime risk of 1.7%1,2; it is a common cause of abrupt-onset hair loss, but occurs less often than androgenetic alopecia or telogen effluvium. Both sexes are equally affected. Although it may occur at any age, incidence at younger ages is higher. Alopecia areata is the most common form of alopecia seen in children. The familial occurrence is approximately 15%, but expression of the disorder is variable between different family members. Of patients suffering from alopecia areata, 5% develop hair loss of their entire scalp hair (alopecia areata totalis) and 1% develop alopecia areata universalis (loss of total body hair).
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Alopecia areata is characterized by an acute onset. It typically presents with oval- or round-shaped, well-circumscribed, bald, patches with a smooth surface in a diffuse distribution (Figs. 87-1 and 87-2). Alopecia totalis results in the loss of the entire scalp hair and may occur suddenly or follow partial alopecia (Fig. 87-3). Partial alopecia may be observed in other areas of the body as well. Loss of total body hair is called alopecia areata universalis and may occur suddenly or follow longstanding partial alopecia.
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Characteristic hallmarks of alopecia areata are so-called black dots (cadaver hairs, point noir), resulting from hair that breaks off by the time it reaches the skin surface. Exclamation point hairs, which have a blunt distal end and taper proximally, appear when the broken hairs (black dots) are ...