Correlations Between Clinical Patterns and Causes of Erythema Multiforme Majus, Stevens-Johnson Syndrome, and Toxic Epidermal Necrolysis

Abstract

UNTIL RECENTLY, most textbooks of medicine considered erythema multiforme to be a spectrum of disorders that included erythema multiforme majus (EMM), Stevens-Johnson syndrome (SJS), and toxic epidermal necrolysis (TEN). A few years ago, an international group of investigators began a large case-control study, the Severe Cutaneous Adverse Reactions (SCAR) study, to determine the risk factors for EMM, SJS, and TEN. As a preliminary step, participants had to agree on definition and classification criteria. After reviewing several hundred photographs of historic cases, they agreed that it was usually possible to distinguish 2 different clinical groups within cases that had been labeled EMM or SJS.¹ In both groups mucous membrane erosions were present, but the individual pattern and distribution of the skin lesions differed. The first group was characterized by acrally distributed targets typical enough to fit the original description of erythema multiforme.² In the second group, including patients with SJS and TEN, the skin lesions were widespread and consisted of blisters arising on erythematous or purpuric macules, closely resembling the original description of SJS.³ Implicit to this new classification were the hypotheses that (1) EMM is different from SJS and (2) SJS and TEN are only severity variants of a single entity.