About Alopecia Areata
Alopecia areata is a common autoimmune skin disease resulting in the loss of hair on the scalp and elsewhere on the body. It usually starts with one or more small, round, smooth patches on the scalp and can progress to total scalp hair loss (alopecia totalis) or complete body hair loss (alopecia universalis).
Alopecia areata affects approximately two percent of the population overall, including more than 5 million people in the United States alone. This common skin disease is highly unpredictable and cyclical. Hair can grow back in or fall out again at any time, and the disease course is different for each person.
The New England Journal of Medicine, April 2012 issue, has a very thorough article on the Medical Progress of Alopecia Areata. You can read the article in its entirety here.