HEALTH TOPICS 
Alopecia areata is a disease in which hair suddenly falls out, leaving round bald patches. In about half of people with alopecia areata, the hair grows back, but may fall out again. In some people, it never grows back.
What causes alopecia areata is still unknown. Scientists suspect it is an autoimmune disease, meaning the body's immune system mistakenly attacks the hair follicles. The painless hair loss mainly affects the scalp, but eyebrows and eyelashes may fall out as well.
Several treatments exist, but with limited effectiveness. These treatments include
- applying a cream containing a corticosteroid drug or minoxidil (Rogaine)
- injecting a corticosteroid drug directly into bald patches
- exposing the bald areas to ultraviolet light
- taking antiviral drugs.
Each treatment has been effective for some people, but none is universally successful. In addition, each has its own side effects or drawbacks.