Secondary causes of pulmonary Eosinophilia: A comprehensive literature review on Loeffler's Syndrome

Loeffler's syndrome, also known as simple pulmonary eosinophilia, represents a distinctive clinical entity characterized by transient pulmonary infiltrates accompanied by peripheral blood eosinophilia. Loffler syndrome is an uncommon, self-limited, benign pulmonary eosinophilia that usually lasts less than a month. This literature review synthesizes current evidence from peer-reviewed publications between 2014 and 2024, examining the etiology, pathophysiology, clinical manifestations, diagnostic approaches, and therapeutic strategies for Loeffler's syndrome and its cardiac variant. The review also addresses the differential diagnosis with other eosinophilic lung diseases and highlights emerging treatment modalities, including targeted biological therapies.