Erythema multiforme (EM), toxic epidermal necrolysis (TEN), and Stevens-Johnson syndrome (SJS). Even
though EM may be entirely distinct, SJS and TEN probably represent different manifestations of a single
disease. A recent classification based on percentage of epidermal detachment defines SJS as denuding <10% of body surface area (BSA), overlapping SJS/TEN as denuding 10–30%, and classic TEN >30%. Bullous EM, previously grouped with SJS, causes epidermal detachment in <10% of BSA, but has acral target lesions or raised atypical targets.
though EM may be entirely distinct, SJS and TEN probably represent different manifestations of a single
disease. A recent classification based on percentage of epidermal detachment defines SJS as denuding <10% of body surface area (BSA), overlapping SJS/TEN as denuding 10–30%, and classic TEN >30%. Bullous EM, previously grouped with SJS, causes epidermal detachment in <10% of BSA, but has acral target lesions or raised atypical targets.