An extraordinary colocalization of alopecia areata and vitiligo.

Although the association of alopecia areata (AA) and vitiligo occurring in the same patient has been frequently reported in the literature, the colocalization of AA and vitiligo is very rare. We report for the first time an adult patient with anatomic concurrence of AA and vitiligo on the scalp. Even though both AA and vitiligo are thought to have the same underlying pathophysiologic mechanisms, the striking rarity of their colocalization challenges this postulated common pathogenesis, and raises the question if autoimmunity is responsible for only a fraction of AA or vitiligo.