Toxic epidermal necrolysis consists of two distinct clinical entities. The Ritter type, seen mostly in children under age 10, is the severest manifestation of staphylococcal disease. A toxin has been isolated which is postulated to be the cause for clinical lesions. High epidermal necrosis occurs. Treatment is with one of the penicillinase-resistant penicillins, and prognosis is good. The Lyell type is seen mostly in adults, is drug-related, and may be the severest form of the Stevens-Johnson syndrome. Full-thickness epidermal necrosis occurs. Treatment consists of withdrawing the offending drug. Good nursing care is essential. Prognosis is guarded.