A drug is defined as any substance used in diagnosis, treatment, or prevention of disease, and an adverse drug reaction may be considered as any unintended or undesired consequence of drug use. With the rapid development of diagnostic and therapeutic drugs, adverse reactions to these agents have become an increasingly important medico-legal problem. Although drug reactions may involve any organ system, cutaneous eruptions are more often recognized because of their visibility. So cutaneous drug eruptions play an important role in early detection of the adverse drug reactions and management for it.
In the adverse drug reactions there are systemic and cutaneous manifestations. The most common systemic reactions in order of frequency are nausea, drowsiness, diarrhea, vomiting, rash, arrhthymias, itching, hyperkalemia, and fever. Severe systemic reactions may lead to be fatal, but in the mild cases the reaction is only limited on the skin. The case/fatality ratio from drug-induced reactions in hospitalized patients varies from 0.24 to 2.9%.
Cutaneous reactions occur in 2 to 3 percent of medical inpatients. The morphologic aspects of drug eruption are protean and frequently bizarre. It includes every possible type of skin Iesion and many reaction patterns, specific and nonspecific.
So it must be kept in mind that the diagnosis of drug eruptions rests upon constant awareness of the capacity of drugs, like any other chemicals, to produce disease.
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