Two major types of EP are acute eosinophilic pneumonia (AEP) and chronic eosinophilic pneumonia (CEP), both of which are characterized by marked accumulation of eosinophils in lung tissues and/or BAL fluid.
Crucial for the diagnosis are the demonstration of pulmonary eosinophilia in the BAL fluid and the exclusion of other disease processes that can present with acute pulmonary infiltrates.