In vitro/ex vivo assays for severe cutaneous drug reactions

Severe cutaneous adverse reactions (SCARs) such as acute generalized exanthematous pustulosis (AGEP), drug reaction with eosinophilia and systemic symptoms (DRESS), and severe skin necrosis and blistering as seen in Stevens-Johnson syndrome (SJS)/toxic epidermal necrolysis (TEN) are presumed to be T-cell–mediated reactions. These occur most commonly in response to a drug precipitant. However, because of the morbidity and mortality of SCAR reactions, in vivo diagnostics (eg, skin testing) have traditionally been deployed in only a few international centers.