Successful Treatment of Imatinib-Induced DRESS Syndrome Using Reslizumab without Cessation of Imatinib: A Case Report.

Drug reaction with eosinophilia and systemic symptoms (DRESS) is a severe cutaneous adverse drug reaction; reported cases are sometimes imatinib mesylate induced. The main treatment is the withdrawal of the causative drug, and most cases with imatinib-induced DRESS syndrome required withdrawal of imatinib. However, in such cases involving anticancer drugs, this may compromise cancer treatment. Herein, we report a patient with imatinib-induced DRESS syndrome that was successfully treated with reslizumab while continuing imatinib treatment. A 65-year-old female presented with facial edema and generalized skin rash after being given 400 mg imatinib 2 weeks ago for metastatic gastrointestinal stromal tumor. After stopping imatinib, the clinical symptoms improved. Imatinib desensitization was performed, and it was administered again. However, the clinical symptoms reappeared more severely 2 months after restart of imatinib, and the peripheral absolute eosinophil count increased to 1,690/μL. A diagnosis of imatinib-induced DRESS syndrome was made, based on the Registry of Severe Cutaneous Adverse Reactions (RegiSCAR) criteria. Imatinib desensitization was repeated, but the clinical symptoms reappeared, and the peripheral eosinophilia persisted. We administered reslizumab, an interleukin-5 monoclonal antibody, without cessation of imatinib. The absolute eosinophil count decreased immediately, and the clinical symptoms improved gradually. After 2 weeks, the clinical symptoms reappeared mildly, but after administering reslizumab again, these disappeared completely. Reslizumab can be considered in the management of DRESS syndrome in cases wherein the causative medication needs to be continued.