Persistent erythema multiforme treated with thalidomide.

Erythema multiforme is a common self-limited disorder that predominantly affects younger individuals. It is characterized by typical iris or target lesions on the skin and mucous membranes. Three clinical subgroups of erythema multiforme have been identified: classical erythema multiforme, recurrent erythema multiforme, and persistent erythema multiforme. By definition, persistent erythema multiforme is characterized by the occurrence of continuous typical and atypical lesions without interruption. We report a 15-year-old boy who developed persistent erythema multiforme for 6 months and responded to treatment with thalidomide.