Clinical classification of cases of toxic epidermal necrolysis, Stevens-Johnson syndrome, and erythema multiforme.

Abstract

To conduct a prospective case-control study about causative factors of severe bullous erythema multiforme, Stevens-Johnson syndrome, and toxic epidermal necrolysis, we needed to define criteria for classifying the cases and standardize the collection of data so that cases could be reliably diagnosed according to this classification. Based on review of case histories and photographs of patients, a group of experts proposed a classification based on the pattern of erythema multiforme-like lesions (categorized as typical targets, raised or flat atypical targets, and purpuric macules) and on the extent of epidermal detachment. An atlas illustrating this classification that included photographs and schematic drawings was developed. We compared the evaluations of 28 cases by four nonphysicians relying on the atlas with the evaluations of the same cases by five experts not using the atlas to determine the usefulness of this atlas for classifying cases according to our nosologic schema.