Alopecia areata

Abstract

• Alopecia areata (AA) is a reversible, initially patchy hair loss most commonly involving the scalp although other regions of the head, including eyelashes and beard, may also be affected. The disease may sometimes lead to complete baldness of the scalp (alopecia areata totalis) or of the entire body (alopecia areata universalis). • The course of AA is usually characterized by phases of acute hair loss followed by spontaneous hair regrowth and waxing and waning of the lesions. However, in severe forms hair loss can persist for many years or even life. • Typical nail changes of AA are pitting, transversal grooves, red spotted lunulae or trachyonychia. • Histopathological features of AA include perifollicular and intrafollicular lymphocytic infiltrates involving only anagen hair follicles with subsequent miniaturization of these structures. • Alopecia areata is regarded as a T-cell-mediated autoimmune disease of the hair follicle that is mediated by CD4+ and CD8+ T-lymphocytes. As with other autoimmune diseases, AA most likely has a polygenic character, where susceptibility is dictated by several major genes and the phenotype may be modified by numerous minor genes. • The most effective treatment for severe AA is the application of a contact sensitizer, while limited AA can be treated by intralesional corticosteroids or clobetasol propionate 0.05% ointment under occlusion. Pulse therapy with systemic corticosteroids or psoralen UV A (PUVA) is often used but neither has yet been proven in controlled studies to be effective in AA. © 2008 Springer-Verlag.