Overlap between maculopapular exanthema and drug reaction with eosinophilia and systemic symptoms among cutaneous adverse drug reactions in a dermatology ward

Summary Background Inpatients with cutaneous adverse drug reactions ( CADR ) with overlapping features between maculopapular exanthema ( MPE ) and drug reaction with eosinophilia and systemic symptoms ( DRESS ) were examined. Objectives To characterize patients with exanthema and few systemic symptoms not meeting the criteria for DRESS [overlapping MPE – DRESS ( MP / DR )]. Methods We undertook a comparative analysis of clinical and laboratory features of patients with MPE , MP / DR and DRESS (2008–12). Results We identified 132 inpatients (85 women/47 men, mean age 64·0 ± 17·7 years) with CADR , 37 with DRESS , 28 with MPE , 34 with MP / DR and 33 with other patterns. There were no significant differences in sex, age or concomitant diseases. Allopurinol was the main cause of DRESS (40·5%) and MP / DR (29·4%); antimicrobials were the main cause in MPE (35·7%). In MP / DR the latency period (18·06 ± 13·17 days) was significantly longer than in MPE but shorter than in DRESS . Although hospitalization time was similar to DRESS (13·26 ± 7·41 days), duration of therapy and follow‐up in MP / DR was shorter. Exanthema/erythroderma were frequently associated with facial oedema in MP / DR (73·5%) and DRESS (89·2%) but only in 42·0% of patients with MPE . MP / DR histopathology showed keratinocyte vacuolization and perivascular and interstitial infiltrate of lymphocytes, eosinophils and neutrophils, similar but milder than in DRESS , with less interface dermatitis, exocytosis and spongiosis. DRESS was associated with liver involvement (78·4%) and eosinophilia (78·4%), but only in 64·7% and 11·8%, respectively, of patients with MP / DR . Conclusions An overlapping pattern between MPE and DRESS was identified and characterized. There may be a continuum spectrum between MPE and DRESS .