A Case of Acute Pericarditis and Hypereosinophilia After Dupilumab Initiation

Dupilumab is a monoclonal antibody approved to treat multiple type 2 inflammatory conditions. Dupilumab-associated hypereosinophilia is a well-documented side effect and typically does not lead to clinical symptoms or pathologic findings. We report a 65-year-old man with asthma and nasal polyposis who presented with pleuritic chest pain after two doses of dupilumab. Our evaluation revealed peripheral hypereosinophilia and pericardial thickening consistent with pericarditis on cardiac MRI. The patient was treated with ibuprofen and colchicine, did not require corticosteroids, and dupilumab was discontinued. Subsequently, his eosinophil counts normalized, and his symptoms resolved. To our knowledge, this is the first published case of dupilumab-induced hypereosinophilia followed by isolated pericardial involvement.