Erythema annulare centrifugum.

Erythema annulare centrifugum (EAC) is a gyrate erythema, which is typically characterized by annular, erythematous plaques with trailing scale. It is considered to be a reactive condition with a wide variety of inciting causes but unclear pathophysiology. The mean duration of the eruption is 11 months. We present a patient with a 50-year history of recurrent EAC with no known cause. Although it does follow a previously reported pattern of seasonal recurrence, this case represents the longest reported duration of EAC.