Three cases of drug‐induced hypersensitivity syndrome associated with mRNA‐based coronavirus disease 2019 vaccines

Drug‐induced hypersensitivity syndrome (DiHS) is a severe drug eruption that can induce reactivation of herpesviruses such as human herpesvirus 6, resulting in symptom flare‐up and organ damage. DiHS is known as drug reaction with eosinophilia and systemic symptoms (DRESS) in Europe. We report three cases of DiHS that could have been triggered by mRNA‐based coronavirus disease 2019 (COVID‐19) vaccines. In these three patients, symptoms of DiHS developed 2–6 days after the first dose of an mRNA‐based COVID‐19 vaccine. Although there have been no reports of DiHS/DRESS induced by mRNA‐based COVID‐19 vaccines in domestic and international journals despite the progress in vaccination worldwide, we speculate that mRNA‐based COVID‐19 vaccines might have triggered the development of DiHS/DRESS in our patients. In the current coronavirus epidemic, it might be important to assess mRNA‐based COVID‐19 vaccination status and date of vaccination when evaluating a patient with DiHS/DRESS.