Drug reaction with eosinophilia and systemic symptoms (DRESS): clinicopathological study of 45 cases

International audienceBACKGROUND: Drug reaction with eosinophilia and systemic symptoms (DRESS) is a rare and severe adverse drug reaction. Large detailed studies of histopathological features of DRESS are sparse and suggest an association between keratinocyte damage and the severity of visceral involvement. OBJECTIVES: To describe the dermatopathological features in a large series of DRESS and their possible association with clinical features and the severity of the disease. METHODS: A retrospective analysis of the clinicobiological and dermatopathological features in a monocentric cohort of patients with DRESS. RESULTS: From January 2005 to January 2013, 45 patients were validated as probable or definite cases of DRESS. The median age was 64~years (range 3-87). The most frequent clinical and biological features included: fever >=38.5°C (95%), facial oedema (72%), enlarged lymph nodes (51%), visceral involvement (75%), blood eosinophilia (97%) and atypical lymphocytes (82%). Severe DRESS occurred in 24% and a fatal outcome in 6% of patients. Histopathological analysis showed that no specific histopathological pattern was characteristic for DRESS. However, several changes in different cutaneous compartments were observed in 2 of 3 of cases. Spongiosis (55%) and keratinocyte damage (53%) were the most common epidermal changes. Spongiosis was associated with non-severe DRESS (P~=~0.041) whereas confluent keratinocyte necrosis correlated with severe DRESS (P~=~0.011). Vascular changes were frequent (88%). A moderate dermal perivascular lymphocytic infiltrate was invariably present, containing eosinophils, neutrophils and/or atypical lymphocytes in 57% of cases. CONCLUSIONS: Epidermal changes are indicative for the severity of DRESS