Diseases

The characteristic finding of alopecia areata is one or more well-circumscribed areas of otherwise normal, hairless skin in hair-bearing areas. Occasionally, it may be necessary to biopsy the scalp to confirm the diagnosis. Other findings that may be helpful are the appearance of short hairs that presumably represent fractured hairs, short thin hairs, and gray hair growing in a bald area. Other causes of hair loss are generally excluded from the consideration by history and clinical evaluation.

The most common pattern is one or more well-defined spots of hair loss on the scalp. If alopecia occurs in an ophiasis pattern (hair loss involving the temporal and posterior scalp) or if large areas of the scalp are involved for long periods of time, the prognosis is worse. A more generalized form of hair loss is referred to as diffuse alopecia areata where there is widespread dramatic thinning of the scalp hair. Occasionally, all of the scalp hair is entirely lost, a condition referred to as alopecia totalis. Less frequently, the loss of all of the hairs on the entire body, called alopecia universalis, occurs.

Current evidence suggests that alopecia areata is caused by an abnormality in the immune system that damages hair follicles. This particular abnormality leads to autoimmunity, a misguided immune system that tends to attack its own body. 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 lymphocytes penetrating into the hair bulb of the hair follicles. Alopecia areata is occasionally associated with other autoimmune conditions such as thyroid disease, vitiligo, lupus, rheumatoid arthritis, and ulcerative colitis. The diagnosis or treatment of these diseases is unlikely to affect the course of alopecia areata. Sometimes, alopecia areata occurs within family members, suggesting a role of genes.

Alopecia areata is an acquired skin disease that can affect all hair-bearing skin and is characterized by localized areas of non-scarring alopecia (hair loss). Alopecia areata is occasionally associated with other medical problems. Most often these bald areas regrow their hair spontaneously.Alopecia areata is rare before 3 years of age. There seems to be a significant inherited predisposition for the development 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 spontaneously. Therefore, there are a variety of treatments, but none of these can confidently be predicted to impact the course of this disease. Local steroid injections intracutaneously may be very helpful in restarting the hair growth cycle in treated areas. Steroid creams, lotions, and shampoos have been used for many years but are of limited benefit at best. Although oral systemic steroids are known to induce hair growth in affected patients, their long-term use is contraindicated because of the likelihood of undesirable side effects.The topical sensitizers, diphencyprone or squaric acid dibutylester, have been used in those suffering from recalcitrant alopecia areata or those with more than 50% hair loss. The goal of treatment is to create an allergic contact dermatitis of the scalp. This alteration in the immune response occasionally is accompanied by hair regrowth. The efficacy of the topical sensitizers has been demonstrated in both young children and adults, but it probably works less than half the time. Recent success using oral janus kinase inhibitors, including tofacitinib, ruxolitinib, and baricitinib, have been shown to be efficacious in severe, extensive alopecia areata in adults, but long-term therapy has potential side effects. The durability of response to these medications is variable, and most patients experience recurrence of hair loss after discontinuation. Perhaps topical therapy with these types of drugs may be available in the near future.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.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.

Alopecia areata tends to occur most often in adults 30 to 60 years of age. However, it can also affect older individuals and, rarely, young children. Alopecia areata is not contagious. It should be distinguished from hair shedding that may occur following the discontinuation of hormonal estrogen and progesterone therapies for birth control or the hair shedding associated with the end of pregnancy. There are a number of treatable conditions that could be confused with alopecia areata.