Drug reaction with eosinophilia and systemic symptoms during primary Epstein–Barr virus infection

We report a drug reaction with eosinophilia and systemic symptoms case of primary Epstein–Barr virus (EBV) infection, in which the diagnosis was first confirmed by lymphocyte transformation tests (LTT). LTTs were positive for cefditoren–pivoxil and acetaminophen. LTT, EBV load, and anti-EBV antibodies could allow early diagnosis of drug reaction with eosinophilia and systemic symptoms, which masquerades with the clinical features of infectious mononucleosis.