Idiopathic eruptive macular pigmentation: a case of 21 years' duration.

Idiopathic eruptive macular pigmentation is a rare condition characterized by asymptomatic pigmented macules involving the neck, trunk, and proximal portions of the extremities. Age at onset usually varies from 1 to 20 years. The lesions usually appear abruptly and remit spontaneously over months to years. An unusual case of a 24-year-old woman with idiopathic eruptive macular pigmentation lasting 21 years was characterized by several periods of spontaneous resolution followed by recurrences.