Among drug exanthemata (AE) are included allergic reactions of the cutaneous system which are of a cutaneous vascular type after hematogenous supply of the allergen, which run an immunological course according to the early, Arthus or late type. They are manifested morphologically as urticaria (monosymptomatic or a partial symptom of an anaphylactic or serum sickness syndrome), as macular or maculopapular exanthema (9 days AE) predominantly after ampicillin, as a fixed AE, as Lyell's disease (fatal in about 30% of cases), as erythema multiforme-like AE, as purpura (allergic vasculitis, "carbromal purpura"), as rare lichenoides or nodose AE and as erythematodes-like drug reactions.