Fast Facts: An Easy-to-Read Series of Publications for the Public
U.S. Department of Health
and Human Services
Public Health Service
National Institute of Arthritis
and Musculoskeletal and
National Institutes of Health
1 AMS Circle
Bethesda, MD 20892–3675
Toll free: 877–22–NIAMS
Web site: www.niams.nih.gov
Updated July 2009
What Is Alopecia Areata?
Alopecia areata is disease that affects the hair follicles, which are part of
the skin from which hairs grow. In most cases, hair falls out in small, round
patches about the size of a quarter. Many people with the disease get only
a few bare patches. Some people may lose more hair. Rarely, the disease
causes total loss of hair on the head or complete loss of hair on the head,
face, and body.
Who Gets Alopecia Areata?
Anyone can have alopecia areata. It often begins in childhood. There is
a slightly increased risk of having the disease if you have a close family
member with the disease.
What Causes Alopecia Areata?
Alopecia areata is an autoimmune disease. Normally the immune system
protects the body against infection and disease. In an autoimmune disease,
the body’s immune system mistakenly attacks some part of your own body.
In alopecia areata, the immune system attacks the hair follicles.
The cause is not known. Scientists think that a person’s genes may play a
role. For people whose genes put them at risk for the disease, some type of
trigger starts the attack on the hair follicles. The triggers may be a virus or
something in the person’s environment.
Will My Hair Ever Grow Back?
There is every chance that your hair will grow back, but it may fall out again.
No one can tell you when it might fall out or grow back. You may lose more
hair, or your hair loss may stop. The hair you have lost may or may not grow
back. Even a person who has lost all of his hair may grow all of his hair back.
The disease varies from person to person.