Distinct clinical phenotypes and outcomes in pediatric chronic eosinophilic pneumonia: a 12- year retrospective cohort study.

Chronic eosinophilic pneumonia (CEP) is a rare interstitial lung disease. Although CEP has been partially characterized in adults, pediatric data remain scarce, which often leads to diagnostic delays and management uncertainty. This retrospective cohort study analyzed demographic, clinical, laboratory, imaging, bronchoalveolar lavage fluid (BALF), and treatment data from children with CEP between 2014 and 2025. Patients were stratified into 'Cured' (complete resolution) and 'Protracted' (persistent symptoms or imaging abnormalities > 3 months) groups for exploratory comparison. Thirteen patients (median age 2.92 years; 61.5% male) were included, with 84.6% having allergic comorbidities. The most common symptoms were productive cough (92.3%) and wheeze (61.5%). Chest CT displayed interlobular septal thickening and ground-glass opacities (each 92.3%). BALF revealed marked eosinophilia (median 46%). After a median follow-up of 35.4 months, 8 patients (61.5%) achieved cure, while 5 (38.5%) had a protracted course. Compared with the Cured group, the Protracted group tended to be younger at onset, displayed more extensive radiographic involvement (100% bilateral, 40% lobar consolidation), received a lower initial corticosteroid dose (0.42 vs. 0.82 mg/kg/day) for a shorter duration (7 vs. 34 days), and exhibited a distinct biomarker profile (lower neutrophil-to-lymphocyte ratio, CRP, and LDH but higher platelet count), along with lower BALF neutrophils (5.0 vs. 24.0%) and higher lymphocytes (13.0 vs. 7.0%).

conclusionPediatric CEP is strongly associated with atopy. The protracted phenotype may be associated with younger age, more extensive radiographic involvement, a platelet-predominant and low-acute-phase biomarker profile, lymphocyte-skewed BALF, and lower initial corticosteroid exposure. Early recognition and adequate initial corticosteroid therapy appear crucial for optimizing outcomes. WHAT IS KNOWN: • CEP is a rare interstitial lung disease that classically affects middle-aged women and is frequently associated with asthma or allergy. • Diagnosis relies on demonstrating pulmonary eosinophilia, and prolonged systemic corticosteroid therapy remains the standard treatment. WHAT IS NEW: • This pediatric cohort reveals that CEP often presents with early onset and male predominance, with outcomes following either a 'Cured' or 'Protracted' course. • The Protracted phenotype may be associated with younger age, specific radiologic findings, lower initial corticosteroid dosing, and elevated platelet counts with lower acute-phase reactants.