Alopecia areata (AA) is a chronic, relapsing, autoimmune disorder characterized by patchy nonscaring hair loss. Although the pathogenesis of alopecia areata is not yet completely elucidated, loss of immune privilege in anagen stage hair follicles is widely accepted to play a key role. Several cytokines that depend on Janus kinase signaling have been identified to be involved in AA, including interleukin (IL)-2, IL-7, IL-15, IL-21, and interferon-γ, making Janus kinase inhibitors an attractive therapeutic target. Available information indicates that about 70% of patients with AA experience significant regrowth, but interruption of treatment is associated with disease recurrence.