Target lesions on the lips: childhood herpes simplex associated with erythema multiforme mimics Stevens-Johnson syndrome.

Erythema multiforme and Stevens-Johnson syndrome are both characterized by areas of epithelial necrosis. An important clinical feature that distinguishes the two is the extensive mucosal necrosis in Stevens-Johnson syndrome but not in erythema multiforme. Because significant and serious complications may develop with Stevens-Johnson syndrome and not with erythema multiforme, it is important to differentiate between the conditions. We describe three boys with herpes simplex virus-associated erythema multiforme who had severe necrosis of the lips develop and were initially diagnosed with Stevens-Johnson syndrome. The lip lesions were large target lesions of erythema multiforme rather than the extensive necrosis seen in Stevens-Johnson syndrome and all three had a benign course.