Severe cutaneous adverse reactions: impact of immunology, genetics, and pharmacology.

Severe cutaneous adverse reactions, though rare, represent a mucocutaneous presentation of adverse drug responses associated with significant morbidity and mortality. Here, we review the recent literature highlighting the roles of selective immune responses, genetic factors, and drug metabolism in increasing susceptibility of a given patient to these rare and severe reactions. Further understanding of these factors and their relative contributions to a severe drug reaction may hold important implications for future patient-specific pharmacogenomic and immunologic profiling in an effort to personalize prescribing patterns by clinicians. Emerging concepts, such as the role of viral reactivation and the presence of overlapping clinical features in severe drug eruptions, are also discussed.