Hematoxylin-eosin (HE) sections of toxic epidermal necrolysis (TEN) (a) and erythema multiforme (EM) (b). (a) Subepidermal bullae under full-thickness epidermal necrosis. Note: the cell-poor dermal inflammation. (b) An interface reaction pattern with infiltrates of lymphocytes and scattered necrotic keratinocytes. Lymphocyte infiltrates are much denser in EM than in TEN. Bar = 100 μm.