Drug reaction with eosinophilia and systemic symptoms (DRESS): an original multisystem adverse drug reaction. Results from the prospective RegiSCAR study

Summary Background Cases of severe drug hypersensitivity, demonstrating a variable spectrum of cutaneous and systemic involvement, are reported under various names, especially drug reaction with eosinophilia and systemic symptoms (DRESS). Case definition and overlap with other severe cutaneous adverse reactions (SCAR) are debated. Objectives To analyse the spectrum of signs and symptoms of DRESS and distribution of causative drugs in a large multicentre series. Patients and methods RegiSCAR, a multinational registry of SCAR, prospectively enrolled 201 potential cases from 2003 to mid‐2009. Using a standardized scoring system, 117 cases were validated as showing probable or definite DRESS. Results The male/female ratio was 0·80; females were borderline significantly younger than males. Next to the ubiquitous exanthema, the main features were eosinophilia (95%), visceral involvement (91%), high fever (90%), atypical lymphocytes (67%), mild mucosal involvement (56%) and lymphadenopathy (54%). The reaction was protracted in all but two patients; two patients died during the acute phase. Drug causality was plausible in 88% of cases. Antiepileptic drugs were involved in 35%, allopurinol in 18%, antimicrobial sulfonamides and dapsone in 12% and other antibiotics in 11%. The median time interval after drug intake was 22 days (interquartile range 17–31) for all drugs with (very) probable causality, with differences between drugs. Conclusion This prospective observational study supports the hypothesis that DRESS is an original phenotype among SCAR in terms of clinical and biological characteristics, causative drugs, and time relation. The diversity of causative drugs was rather limited, and mortality was lower than that suggested by prior publications. What's already known about this topic? DRESS is a hypersensitivity reaction, characterized by a variable combination of symptomatic and asymptomatic features. What does this study add? DRESS is an original phenotype among severe cutaneous adverse reactions in terms of clinical and biological characteristics, drugs, time relation, and course. Besides eosinophilia, other haematological abnormalities are frequent. The diversity of causative drugs is rather limited. The prodromal period is quite variable, introducing risk of protopathic bias, especially for antibiotics and NSAIDs.