[Alopecia areata. Clinical aspects, pathogenesis and rational therapy of a T-cell-induced autoimmune disease].

Alopecia areata is a T-cell mediated autoimmune disease directed against an unknown auto antigen of the hair follicle. There is a genetic predisposition to develop alopecia areata, whereas environmental triggers have so far not been identified. The diagnosis can be established by characteristic clinical features of alopecia areata including its severe forms alopecia areata totalis and universalis. Nail changes may help confirm the diagnosis. On rare occasions a histopathological examination may be necessary, whereas other laboratory investigations are unnecessary. Because of the high rate of spontaneous remission, the efficacy of a rational treatment of alopecia areata has to be proven in controlled studies and it should be associated with only minor side effects. According to the rules of evidence-based medicine, treatment with a contact sensitizer is at present the most effective treatment of alopecia areata showing only mild side effects. However, it is time-consuming and in some cases ineffective, making it desirable to develop new, more specific forms of treatment.