[Drug-induced fever: a diagnosis to remember]

Drug fever (DF) is a febrile reaction induced by a drug without additional clinical features like skin eruption. This adverse drug reaction is probably common but under diagnosed. While its outcome is generally favourable, DF generates unnecessary diagnostic procedures as well as hospitalisations or hospitalisation prolongations. Clinical presentation and biological findings are not specific. Fever is generally well tolerated but may be accompanied by general symptoms mimicking sepsis. Moderate biological disorders could be expected, including elevation or decrease in white blood cell count, eosinophilia, liver cytolysis, and increased C-reactive protein. An infection should be systematically ruled out. Clinical or biological signs of severity should question DF diagnosis. When DF is suspected, the involved drug(s) should be stopped after a reliable assessment of imputability. Antibiotics represent the most often implicated drugs. Fever disappearance after discontinuing the suspected drug is the cornerstone of DF diagnosis. Before stopping the administration of the suspected drug(s), a risk/benefit ratio assessment is necessary. Consistently, it may be complicated to stop an antimicrobial drug when treating an infection or an immunosuppressive drug if required.