What is alopecia areata?
Alopecia areata is a hair-loss condition which usually affects the scalp. It can, however, sometimes affect other areas of the body. Hair loss tends to be rather rapid and often involves one side of the head more than the other.
Alopecia areata affects both males and females. This type of hair loss is different than male-pattern baldness, an inherited condition.
What causes alopecia areata?
Current evidence suggests that alopecia areata is caused by an abnormality in the immune system. This particular abnormality leads to autoimmunity. As a result, the immune system attacks particular tissues of the body. In alopecia areata, for unknown reasons, the body's own immune system attacks the hair follicles and disrupts normal hair formation. Biopsies of affected skin show immune cells inside of the hair follicles where they are not normally present. What causes this is unknown. Alopecia areata is sometimes associated with other autoimmune conditions such as allergic disorders, thyroid disease, vitiligo, lupus, rheumatoid arthritis, and ulcerative colitis. Sometimes, alopecia areata occurs within family members, suggesting a role of genes and heredity.