Abstract: Alopecia areata (AA) is an autoimmune dermatological disease characterized by non-scarring hair loss, its etiology is still unknown, it could be related to environment, heredity and immunity. It is well accepted that the “loss of immune immunity” of hair follicles during the growth period plays an important role in the etiology of AA. In recent years,  the common immunological characteristics of AA and other autoimmune diseases have been discovered, and a variety of new biological agents have been gradually tried to apply to treat severe AA and those with poor efficacy of traditional therapies. The update of the immunologic mechanism of alopecia areata is reviewed in this paper.

Key words: alopecia areata, immune pathways, cytokines