Definition of Alopecia areata:

Alopecia areata is a condition that causes round patches of hair loss, and can lead to total hair loss.

Causes, incidence, and risk factors:

The cause of alopecia areata is unknown. About a fifth of people with this condition have a family history of alopecia.

Alopecia areata is thought to be an autoimmune condition. This occurs when the immune system mistakenly attacks and destroys healthy body tissue.

Alopecia areata is seen in men, women, and children. A major life event such as an illness, pregnancy, or trauma occurs before the hair loss in some, but not most patients

Forms of alopecia include:

• Alopecia areata -- patches of hair loss, usually on the scalp, but they also can be in the beard or other areas
• Alopecia totalis -- complete loss of scalp hair
• Alopecia universalis -- total loss of all body hair

See also:

• Female pattern baldness
• Hair loss
• Male pattern baldness