Definition of Alopecia areata:

Alopecia areata is a condition that causes round patches of 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 may sometimes occur with autoimmune diseases.

Forms of alopecia include:

• Alopecia totalis -- complete loss of scalp hair
• Alopecia universalis -- total loss of all body hair

Symptoms:

• Loss of all scalp and body hair (alopecia universalis)
• Loss of all scalp hair (alopecia totalis)
• Roundish patches of hair loss on the head
• Smooth, hairless scalp in the affected areas

Hairs that look like exclamation points are sometimes seen at the edges of a bald patch.

Signs and tests:

On occasion, a scalp biopsy may be performed. Several blood tests may be done, because alopecia areata may occur with autoimmune conditions.

Treatment:

No fully effective treatments are available. Typical therapy includes:

• Steroid injection under the skin surface
• Topical corticosteroids
• Ultraviolet light therapy

Irritating drugs may be applied to hairless areas to cause the hair to regrow.

Expectations (prognosis):

Full recovery of hair is common. However, some people may have a poorer outcome, including those with:

• Alopecia areata at a young age
• Eczema (atopic dermatitis)
• Long-term alopecia

Complications:

Permanent hair loss is a possible complication of alopecia areata.

Calling your health care provider:

Call for an appointment with your health care provider if you are concerned about hair loss.