Methods: A prospective study was developed in Allergy Clinics of two Services in São Paulo, Brazil, from November 2008 to June 2011. The patients were studied based on history of DRESS based on standardized scoring systems and using an adapted ENDA (European Network of Drug Allergy) questionnaire. Clinical and demographic data were analysed.
Results: Twenty-nine cases were validated as probable or definitive DRESS, 20 females (69%) and the mean age was 43,6. The reactions generally started with fever and exanthema. All cases had exanthema, mucosal involvement was found in 4 patients (13%). Fever >38oC was present in 89% and lymphadenopathy in 55%. Involvement of a single internal organ (69%) or variable combination of 2 or more internal organs (17%) was common, predominantly related to liver (79%), kidney (17%) and lung (6,8%). Eighty percent of patients with renal involvement required dialysis. Eosinophilia was documented in 89% and atypical lymphocytes in 31%. Sixty-nine percent were related with antiepileptics, 10% with sulfonamides and 6,8% with allopurinol, 6,8% with β-lactams antibiotics and 6,8% with non-steroidal anti-inflammatory drugs. The mean interval between the intake of the suspected drug and the reaction was 27,6. In all patients the duration of the reaction was protracted (> 15 days). Forty-eight patients reported the intake of more than 2 drugs at the same time of the reaction, but in all cases there was 01 drug suspected. No fatalities occurred.
Conclusions: This series confirmed the clinical variability of DRESS, highlighting skin, fever, lymphadenopathy, internal organs involvement and eosinophilia. There was severe internal organ involvement, but no fatalities occurred. Clinical characters and time of onset of the reactions differs from others non-immediate hypersensitivity reactions, it supports that DRESS is an original phenotype. Prospective long-term multicentric epidemiological studies may be important for better understanding of this syndrome.