Alopecia areata is believed to be an autoimmune disease resulting from a breach in the immune privilege of the hair follicles. Risk factors include a family history of the condition. Among identical twins, if one is affected, the other has about a 50% chance of also being affected. The underlying mechanism involves failure by the body to recognize its own cells with subsequent immune mediated destruction of the hair follicle.
No cure for the condition is known. Efforts may be used to try to speed hair regrowth such as cortisone injections. Sunscreen, head coverings to protect from cold and sun, and glasses if the eyelashes are missing are recommended. In some cases, the hair regrows and the condition does not reoccur. In others, hair loss and regrowth occurs over years. Among those in whom all body hair is lost, less than 10% recover.
About 0.15% of people are affected at any one time and 2% of people are affected at some point in time. Onset is usually in childhood. Males and females have the condition in equal numbers. The condition does not affect a person’s life expectancy.