Single-cell RNA analysis: guiding the treatment of DiHS/DRESS

Drug‐induced hypersensitivity syndrome (DiHS)—also termed as drug reaction with eosinophilia and systemic symptoms (DRESS)—is a potentially lethal inflammatory disease associated with human herpesvirus (HHV) reactivation. DiHS/DRESS is classified within a group of syndromes named severe cutaneous adverse reactions (SCARs), including acute generalized exanthematous pustulosis and Stevens‐Johnson syndrome/toxic epidermal necrolysis. SCARs are delayed type IV hypersensitivity reactions mainly characterized by T‐cell activation. The most commonly encountered dermatological manifestation of DRESS is an erythematous morbilliform rash, sometimes complicated by vesicles, bullae, atypical targetoid plaques, purpura, or sterile small pustules, or even progress to exfoliative dermatitis or erythroderma. The pathophysiology of DRESS is still poorly understood.1 The proposed mechanisms implicated in its pathogenesis include drug detoxification enzyme abnormalities, sequential reactivation of herpesviruses (cytomegalovirus, Epstein‐Barr virus, HHV‐6 and ‐7), and genetic predisposition related to certain human leukocyte antigen alleles. The limited knowledge of the mechanisms and pathways underlying the pathology of DRESS present an important treatment hurdle.