Nasal nitric oxide is a useful biomarker for acute unilateral maxillary sinusitis in pediatric allergic rhinitis: A prospective observational cohort study.

Background: Nasal nitric oxide (nNO) could be a biomarker for nasal passage inflammation and sinus ostial patency. We have aimed to investigate the nNO concentration and the effect of antibiotic therapy in children with perennial allergic rhinitis (PAR) children with/without acute bacterial sinusitis.

Methods: We enrolled a cohort of 90 and 31 children with PAR, without and with acute unilateral maxillary sinusitis, and 79 normal children. Acute bacterial maxillary sinusitis was diagnosed based on clinical signs and symptoms, radiographic examination and nasal fibroendoscopy. Rhinitis control assessment test (RCAT), rhinomanometry, nNO and fractional exhaled NO (FENO) measurements were performed before and 2 weeks after antibiotic therapy.

Results: We found significantly higher mean nNO levels, FENO values, and total nasal resistance in children with PAR than in normal children ( ​< ​0.05). Acute unilateral maxillary sinusitis was associated with lower lesion-side nNO levels, higher FENO values, total nasal resistance, and poor RCAT scores ( ​< ​0.05). In multivariate analysis, age, IgE, and acute maxillary sinusitis were significant factors influencing nNO levels in children with PAR. The lesion-side nNO levels, FENO values, total nasal resistance, and RCAT scores were reversed after antibiotic therapy ( ​< ​0.05). The lesion-side nNO levels were significantly correlated to nasal obstructive scores ( ​= ​0.59,  ​< ​0.05) and expiratory nasal resistance ( ​= ​-0.54,  ​< ​0.05) in the acute maxillary sinusitis. A cut-off nNO value of 538 ​ppb showed 100% sensitivity and 94.9% specificity, to predict PAR from normal children. An nNO value of 462 ​ppb showed 100% sensitivity and 100% specificity to discriminate between the lesion-side and the unaffected sinus-side in PAR children with acute unilateral maxillary sinusitis.

Conclusions: We conclude that the obstruction of NO from the sinus into the nasal passage is the likely explanation for the decreased lesion-side nNO levels in acute unilateral maxillary sinusitis. nNO is a non-invasive biomarker with high sensitivity to diagnose and monitor treatment responses of PAR patients with acute rhinosinusitis. Both nNO and FENO levels return to baseline following antibiotic therapy, supporting the "one airway one disease" concept.