Which of the following can cause pulmonary eosinophilia?
High-Yield Explanation
Inhaled or ingested extrinsic factors, including medications and infectious agents (eg, parasites, fungi, mycobacteria), may trigger an eosinophilic immune response. This may be mild and self-limited, as in Loeffler syndrome. Intrinsic pulmonary eosinophilic syndromes are generally idiopathic in nature. They include a diverse group of autoimmune and idiopathic syndromes ranging from blood dyscrasias to vasculitis. This group includes chronic eosinophilic pneumonia (CEP), idiopathic hypereosinophilic syndrome (IHES), Churg-Strauss syndrome (CSS), and eosinophilic granuloma (EG; pulmonary histiocytosis X or Langerhans cell granulomatosis).