Erythema Multiforme and Stevens - Johnson Syndrome Are Histologically Distinct

Recently, it has been suggested that severe erythema multiforme (EM) and Stevens - Johnson syndrome (SJS) are two distinct entities. That conclusion was based on a study of clinical and epidemiologic data. To determine if the two diseases differ histologically, the authors of the present study retrospectively reviewed histologic features of 38 patients with a clinical diagnosis of severe EM or SJS.

Two discrete histologic patterns were apparent. Biopsies from patients with severe EM showed a lichenoid inflammatory infiltrate with prominent exocytosis and keratinocyte necrosis limited to the basal layer. In contrast, patients with SJS demonstrated marked necrosis of the epidermis and only a minimal inflammatory infiltrate with much less exocy…