Eosinophilic Cardiomyopathy in Eosinophilic Granulomatosis With Polyangiitis After Dupilumab Therapy

BACKGROUND: Dupilumab, an IL-4Rα antagonist used in type 2 inflammatory diseases, is associated with transient peripheral eosinophilia, yet progression to eosinophilic granulomatosis with polyangiitis (EGPA) remains rare. CASE SUMMARY: A 64-year-old man presented with acute chest pain, dyspnea, marked hypereosinophilia, elevated cardiac biomarkers, and systemic symptoms 3 months after dupilumab initiation. Echocardiography and cardiac magnetic resonance imaging demonstrated left ventricular dysfunction, and endomyocardial biopsy confirmed eosinophilic myocarditis. High-dose corticosteroids and cyclophosphamide led to rapid clinical improvement. DISCUSSION: This case shows severe eosinophilic myocarditis in the context of dupilumab therapy. Current literature suggests biologic therapy may unmask underlying EGPA rather than directly induce vasculitis, emphasizing the need for vigilance. TAKE-HOME MESSAGES: Dupilumab-associated eosinophilia warrants careful eosinophil monitoring. New systemic or cardiac symptoms should prompt evaluation for EGPA, using multimodality imaging with a low threshold for performing endomyocardial biopsy.