There is an enormous variety of cutaneous reactions to drugs, with many clinical patterns. The diagnosis of drug eruption is usually based on clinical suspicion and not confirmed by rechallenge. In children, viral exanthems and drug eruptions may be very difficult to distinguish. Drug eruptions can mimic virtually all the morphologic expressions in dermatology and must be the first to be considered in the differential of symmetric eruption of sudden appearance. Commonly seen types of drug eruptions include morbilliform (aka measles-like or "maculopapular") drug eruptions, and urticarial drug eruptions (hives).