Alopecia Areata

Alopecia areata is a disease that happens when the immune system attacks hair follicles and causes hair loss. While hair can be lost from any part of the body, alopecia areata usually affects the head and face. Hair typically falls out in small, round patches about the size of a quarter, but in some cases, hair loss is more extensive. Most people with the disease are healthy and have no other symptoms. Researchers do not fully understand what causes the immune attack on hair follicles, but they believe that both genetic and environmental (non-genetic) factors play a role.