An inflammatory lung disorder characterized by an increased number of eosinophils in the lungs. The majority of cases are idiopathic, without identifiable cause. In a minority of cases, medications, fungal infections, and environmental triggers have been implicated. It manifests as acute or chronic. Acute eosinophilic pneumonia is a severe and rapidly progressing pneumonia that may lead to respiratory failure requiring mechanical ventilation. Chronic eosinophilic pneumonia follows a slower course and manifests as fever, dyspnea, cough, and weight loss.