Drug-related relapses in drug reaction with eosinophilia and systemic symptoms (DRESS)

BACKGROUND: A drug reaction with eosinophilia and systemic symptoms (DRESS) is a severe T cell mediated hypersensitivity reaction. Relapses of symptoms in the recovery phase are frequent and linked to the reduction of the corticosteroid treatment, to viral reactivations or to the exposure to new drugs. Here, we analyzed, how often the exposure to new drugs leads to new sensitization or drug-related relapses without detectable sensitization. METHODS: 46 patients with DRESS treated in the allergy division of the Inselspital, Bern University Hospital, were retrospectively assessed. Drug-related relapses were analyzed in terms of frequency and whether a possible sensitization evaluated by skin tests and/or lymphocyte transformation tests (LTT) to the new drugs was detectable. Furthermore, drug tolerance was evaluated in a subset of patients. RESULTS: 56 relapses were observed in 27 of 46 patients with DRESS (58.7%). 33 (58.9%) of these relapses were associated with the use of new drugs, 30 drug-related relapses were evaluated by patch test and/or lymphocyte transformation test. In 8/30 (26.7%) drug-related relapses, a sensitization to the new drug was demonstrated, suggesting the emergence of a multiple drug hypersensitivity syndrome (MDH). 14 patients experienced 22 drug-related relapses without any detectable sensitization and only 1/6 patients developed new symptoms upon reexposure. CONCLUSION: Patients with DRESS frequently suffered from drug related relapses. Half of the patients with drug-related relapses developed a MDH with proven sensitizations not only to the DRESS inducing drugs, but also to newly applied drugs. When not sensitized, drugs involved in drug related relapses could be reintroduced, if needed. Here, we propose a procedure for drug testing and future management of drug-related relapses in DRESS.