Alopecia areata is patchy baldness (alopecia means baldness and areata means occurring in patches), which typically begins with patchy hair loss on the scalp and sometimes progresses to complete baldness and even loss of body hair. The hair loss tends to be rather rapid and asymmetrical and is different than male pattern baldness.
Alopecia areata affects both males and females. It tends to occur most often in children and young adults but older individuals can also be affected.
The most common pattern of alopecia areata is one or more spots of hair loss on the scalp. There is also a form with more generalized thinning. When all of the scalp hair is lost, it is called alopecia totalis. Loss of all of the hairs on the body is called alopecia universalis.
The cause appears to involve an autoimmune mechanism. The body's own immune system attacks the hair follicles and disrupts normal hair formation. Biopsies of affected skin show lymphocytes (one of the body's immune system cells) inside of hair follicles where lymphocytes normally are not present. What causes this is unknown.
Alopecia areata is sometimes associated with other conditions (allergic disorders, thyroid disease, vitiligo, lupus, rheumatoid arthritis, ulcerative colitis). Some cases occur within family members and indicate a genetic basis.
The characteristic diagnostic finding of alopecia areata is the exclamation point hair. These can be found in areas of hair loss and are short broken off hairs that are narrower closer to the scalp and therefore mimic an exclamation point. In some cases a biopsy is necessary for diagnosis.
In about half of cases, the hair regrows within a year without any treatment. The longer the period of time of hair loss, the less chance that it will regrow and a variety of treatments can be tried. Steroid injections and cream to the scalp have been used for many years. Other drugs include minoxidil, irritants, and topical immunotherapy which may be used in different combinations.