IntroductionCutaneous drug eruptions may be defined as adverse cutaneous lesions as a consequence of administration of drugs.
The pathogenesis of drug eruptions may arise as a result of immunological or non-immunological reaction. Some of these reactions are predictable (dose-related) while some are unpredictable (idiosyncratic). Those with an immunological basis may due to different types of hypersensitivity reactions, for instance, allergic type of urticaria may be the result of Type I reaction (IgE-mediated) or Type III reaction (complement dependent immune-complex mediated). Nevertheless, the exact mechanisms of most drug eruptions, including fixed drug eruptions, are unknown.