(1243) Improvement in Nasal Eosinophilia in Pediatric Chronic Rhinitis on Dupilumab: A Case Report

Introduction: Chronic rhinitis affects about 20% of children in the United States and can be driven by Th2-mediated Type II inflammation. This process promotes persistent eosinophil activity and, in select patients, can progress to nasal polyps. While there is growing interest in identifying early signs of Th2 disease and understanding which children are at risk for developing chronic rhinosinusitis with nasal polyps (CRSwNP), current clinical tools offer limited ways to endotype pediatric patients. Nasal cytology is a simple, inexpensive way to identify inflammatory patterns and potentially follow treatment response. Dupilumab, which blocks the shared IL-4/IL-13 receptor subunit, targets upstream Th2 signaling and may help prevent progression toward CRSwNP.

Methods: EB is a 12-year-old boy with longstanding chronic rhinitis, recurrent sinus infections, congestion, and hyposmia refractory to antihistamines for > 2 years, intranasal steroids for >4 years and adenoidectomy. He initiated dupilumab therapy in September 2025 for refractory asthma and eczema.

Results: At the time of biologic therapy initiation, his Lund-Kennedy score was 3 and his SN-5 was 6.2/7 with overall quality of life (QOL) 4/10. Nasal cytology showed 2+ eosinophilia, and bloodwork confirmed peripheral eosinophilia. After three doses of dupilumab over two months, his Lund-Kennedy score improved to 2, his SN-5 to 5.4/7, and QOL 7/10. Repeat nasal cytology showed absence of eosinophilia.

Conclusions: We present a unique case of subjective and objective improvement of rhinologic disease after dupilumab that suggests biologics may benefit select pediatric cases with nasal eosinophilia who fail standard therapy. While nasal cytology is not routinely used as an outcome measure in pediatric CRSwNP, this case highlights its potential as a low-cost, easily repeatable tool to characterize inflammation and track treatment response over time. These findings support the growing consideration of biologics as adjunctive therapy in pediatric nasal polyposis and suggest that nasal cytology may help guide and monitor such interventions in clinical practice.