Alpecia areata widely regarded being a tissue-specific autoimmune disease in which the body attacks its own hair follicles and suppresses or hinders hair growth.
The characteristic patchy hair loss in sharply defined areas is most apparent on the surface of the scalp. In some patients it progresses to a total scalp hair loss (alopecia totalis) and a total body hair loss (alopecia universalis). The hitherto incurable disease affects 0,1% - 0,2% of the population, predominantly children, adolescents and young adults. Albeit not life threatening, the disease usually has devastating effects on the patient's quality of life and self esteem, which can result in considerable levels of anxiety and increased risk of depression.
Source: http.// dermis.net 02/2014