الفهرس 
Alopecia AreataOnly 14 pages are availabe for public view
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Abstract
Alopecia areata is a common type of hair loss. It occurs in either sex, and any age can be affected. It usually presented with an oval patch or multiple confluent patches of asymptomatic, well-circumscribed, non-scarring alopecia areata that regrow spontaneously, but may also persist or progress to all scalp hair (alopecia totalis) or all body hair, including eyebrows and eyelashes (alopecia universalis).
The histologic hallmark features of active AA are a dense or moderate lymphocytic infiltrate develops around the anagen hair bulb, with great loss of anagen hairs and relative increase in telogen hairs. In the chronic stage, a new normal hair grows, if there is no inflammation at this time. If inflammation is still present, it is likely that the hair will be miniaturized, with decreased follicle density and many fibrous tracts, with some lymphoid cells or pigment incontinence are seen.
Although there are several hypotheses proposed the etiology of AA, many factors have been described such as genetic susceptibility, the atopic state, non- specific autoimmune reactions, neurological factors, infectious agents, and possible emotional stress.