Alopecia Areata

Definition

Definition of Alopecia Areata
Alopecia areata (AA) is a medical condition in which hair is lost from some or all areas of the body, usually from the scalp. Because it causes bald spots on the scalp, especially in the first stages, it is sometimes called spot baldness. In 1–2% of cases, the condition can spread to the entire scalp (Alopecia totalis) or to the entire epidermis (Alopecia universalis). Conditions resembling AA, and having a similar cause, occur also in other species.

Symptoms

Symptoms of Alopecia Areata
Typical first symptoms of alopecia areata are small bald patches. The underlying skin is unscarred and looks superficially normal. These patches can take many shapes, but are most usually round or oval. Alopecia areata most often affects the scalp and beard, but may occur on any hair-bearing part of the body. Different skin areas can exhibit hair loss and regrowth at the same time. The disease may also go into remission for a time, or permanently. Common in children.

Causes

Causes of Alopecia Areata
Alopecia areata is not contagious. It occurs more frequently in people who have affected family members, suggesting that heredity may be a factor. Strong evidence that genes may increase risk for alopecia areata was found by studying families with two or more affected members. This study identified at least four regions in the genome that are likely to contain alopecia areata genes. In addition, it is slightly more likely to occur in people who have relatives with autoimmune diseases.

The condition is thought to be an autoimmune disorder in which the body attacks its own hair follicles and suppresses or stops hair growth. For example, T cell lymphocytes cluster around affected follicles, causing inflammation and subsequent hair loss. There are a few recorded cases of babies being born with congenital alopecia areata; however, these are not cases of autoimmune disease because an infant is born without a fully developed immune system.

Diagnosis

Diagnosis of Alopecia Areata
Alopecia areata is usually diagnosed based on clinical features.

Trichoscopy may aid differential diagnosis. In alopecia areata trichoscopy shows regularly distributed "yellow dots" (hyperkeratotic plugs), micro-exclamation mark hairs, and "black dots" (destroyed hairs in the hair follicle opening).

A biopsy is rarely needed in alopecia areata. Histologic findings include peribulbar lymphocytic infiltrate ("swarm of bees"). Occasionally, in inactive alopecia areata, no inflammatory infiltrates are found. Other helpful findings include pigment incontinence in the hair bulb and follicular stelae and a shift in the anagen-to-telogen ratio towards telogen.

Treatment

Treatment of Alopecia Areata
The course of typical alopecia areata is not predictable with a high likelihood of spontaneous remission. The longer the period of time of hair loss and the larger the area involved, the less likely the hair will regrow. Therefore, there are a variety of treatments, but none of these can confidently be predicted to impact the course of this disease. Steroid injections, creams, and shampoos (such as clobetasol {Clobex} or fluocinonide {Lidex}) for the scalp have been used for many years.

As with many chronic disorders for which there is no single treatment, a variety of remedies are promoted which in fact have no benefit. There is no known effective method of prevention, although the elimination of emotional stress is felt to be helpful. No drugs or hair-care products have been associated with the onset of alopecia areata. Much research remains to be completed on this complex condition.

Although not precisely a treatment, the cosmetic camouflage of alopecia areata is certainly an important consideration in patient management. The damaging emotional effect of significant hair loss for both women and men can be considerable.

Prognosis

Prognosis of Alopecia Areata
Full recovery of hair is common.

Prevention

Prevention of Alopecia Areata
Alopecia areata cannot be prevented.