Toxic epidermal necrolysis. Rapid differentiation between staphylococcal- and drug-induced disease.

Based on the difference in the level of epidermal split, staphylococcal-induced toxic epidermal necrolysis (TEN) can be rapidly differentiated from drug-induced TEN. The microscopic pathologic findings of the staphylococcal-induced disease shows epidermal cleavage high in the malpighian layer, while the nonstaphylococcal-induced disease shows a subepidermal split. Rapid differentiation is accomplished by histologically examining a frozen section of peeled skin obtained from a fresh lesion of TEN and by performing a Tzanck preparation on the denuded base. In order to illustrate these techniques, we present the cases of two adult patients with TEN; in one the disease was staphylococcal-induced while in the other it was drug-induced.