Eosinophilic Myocarditis: From Bench to Bedside

Myocarditis is a polymorphic and potentially life-threatening disease characterized by a large variability in clinical presentation and prognosis. Within the broad spectrum of etiology, eosinophilic myocarditis represents a rare condition characterized by eosinophilic infiltration of the myocardium, usually associated with peripheral eosinophilia. Albeit uncommon, eosinophilic myocarditis could be potentially life-threatening, ranging from mild asymptomatic disease to multifocal widespread infiltrates associated with myocardial necrosis, thrombotic complications, and endomyocardial fibrosis. Moreover, it could progress to dilated cardiomyopathy, resulting in a poor prognosis. The leading causes of eosinophilic myocarditis are hypersensitivity reactions, eosinophilic granulomatosis with polyangiitis, cancer, hyper-eosinophilic syndrome variants, and infections. A thorough evaluation and accurate diagnosis are crucial to identifying the underlying cause and defining the appropriate therapeutic strategy. On these bases, this comprehensive review aims to summarize the current knowledge on eosinophilic myocarditis, providing a schematic and practical approach to diagnosing, evaluating, and treating eosinophilic myocarditis.