D2.86 - Nasal Nitric Oxide in Routine Practice: Results of a One-Year Clinical Experience in Pediatric Allergology

As the measurement of nasal nitric oxide (nNO) becomes increasingly accessible in routine clinical settings, its utility is expanding beyond specialized orphan disease centers into general pediatric allergology. This study aimed to present our one-year real-world clinical experience of integrating nNO measurements into the evaluation of pediatric patients presenting with diverse and complex chronic nasal symptoms.

We retrospectively analyzed data from 44 children who underwent nNO testing (measured in parts per billion, ppb) at our university allergy and immunology center over the past year. Notably, patients with suspected orphan conditions within this cohort were specifically referred for evaluation from the Kyiv Center for Orphan Diseases. Following comprehensive clinical, allergological, and genetic verification, the patients were categorized into six real-world clinical phenotypes: classic allergic rhinitis (AR, n=12), local allergic rhinitis (LAR, n=7), non-allergic controls with excluded orphan diseases (n=14), chronic rhinosinusitis with nasal polyps and they surgical threatment in the past (CRSwNP, n=5), cystic fibrosis (CF, n=4), and primary ciliary dyskinesia (PCD, n=2).

The practical application of nNO revealed distinct patterns across the observed cohorts. Patients with LAR and AR demonstrated the highest nNO values, reflecting pronounced local eosinophilic inflammation (LAR median: 675 ppb, range: 589-1124; AR median: 548 ppb, range: 444-1281). The control group exhibited expected baseline values (median: 389 ppb, range: 291-882). In contrast, the method consistently identified abnormally low levels in the PCD group (56 and 111 ppb) and moderately reduced levels in CF patients (median: 178.5 ppb, range: 87-311). The CRSwNP cohort showed wide intermediate variability (median: 192 ppb, range: 145-721)

The increasing availability of nNO measurement provides allergists with a highly valuable, non-invasive objective tool for everyday practice. Our one-year experience demonstrates that routine nNO assessment is highly effective not only for confidently ruling out severe underlying conditions like PCD and CF but also for actively supporting the diagnosis of eosinophilic-driven diseases such as LAR and AR, thereby facilitating timely and targeted management.