Alopecia areata.

Alopecia areata (AA) is a common, non-scarring alopecia that usually presents as well-circumscribed patches of sudden hair loss and affects 0.1-0.2% of the population. The aetiology of AA is thought to be both genetic and autoimmune in nature. One hundred and thirty-nine single nucleotide polymorphisms linked to AA have been identified in 8 regions of the genome and have been found to be associated with T cells or the hair follicle. Furthermore, patients with AA have been found to have an increased frequency of hair follicle-specific auto-antibodies. The diagnosis of AA is usually made on clinical grounds, and further investigations are not usually needed. Intralesional corticosteroids remain the treatment of choice. Systemic steroids are also highly effective; however, side effects make them less desirable to both patients and physicians. Other available treatment options include anthralin, minoxidil, topical immunotherapy and systemic immunosuppressants. These treatments will be discussed in depth in this chapter. The morbidity of AA is largely psychological; therefore, the successful treatment of AA should include focusing on improving the psychological impact of this condition.