Chronic Eosinophilic Pneumonia in an Adolescent Without Known Risk Factors: A Case Report on a Challenging Lung Disease.

Chronic eosinophilic pneumonia (CEP) is a rare lung disease characterized by eosinophilic infiltration of the lungs. It typically presents with nonspecific respiratory symptoms and can mimic more common conditions such as community-acquired pneumonia (CAP), especially in children, making early diagnosis challenging. We report the case of a previously healthy 15-year-old girl who presented with a seven-week history of fever, cough, dyspnea, and pleuritic chest pain. Initial treatment for presumed CAP with an inflammatory component, including antibiotics and corticosteroids, provided only transient relief. Persistent symptoms, worsening radiographic findings, and marked peripheral eosinophilia raised concern for an alternative diagnosis. An extensive infectious and autoimmune workup was negative. Bronchoalveolar lavage revealed eosinophilia, and lung biopsy ultimately confirmed CEP. The patient responded dramatically to systemic corticosteroids, with rapid clinical improvement. This case highlights the diagnostic complexity of CEP in pediatric patients. It underscores the importance of considering eosinophilic lung diseases in cases of recurrent or nonresolving pneumonia, especially when peripheral eosinophilia and characteristic imaging findings are present. Early recognition and treatment with corticosteroids are crucial for a favorable outcome.