Question: What is (are) Alopecia areata ?
Answer: Alopecia areata (AA) is an autoimmune disease in which the immune system mistakenly attacks the hair follicles. In most cases, hair falls out in small, round patches on the scalp. Although uncommon, hair loss can be more extensive in some people and affect other parts of the body. This condition can progress to complete loss of scalp hair (alopecia totalis) or total loss of all body hair (alopecia universalis). Although the exact cause of AA is unknown, roughly 20% of affected people have a family member with alopecia, suggesting that genetic factors may contribute to the development of the condition. There is no cure or approved therapy for AA; however, some people find that medications approved for other purposes can help regrow hair.
Source: GARD