The effect of medical treatment on nasal exhaled nitric oxide (NO) in patients with persistent allergic rhinitis: A randomized control study

Purpose: This study aimed to evaluate the role of nasal nitric oxide (NO) in the management of patients with persistent allergic rhinitis (PER). Methods: It was a randomized and comparative study. The study subjects were classified as controls (healthy subjects) or patients with PER based on defined criteria. All clinical, functional and biological data were collected for analyzing. Nasal fractional exhaled nitric oxide (FENO) was measured by electroluminescence device. Patients with PER were randomized for treatment with antihistamine (ATH) combined with leukotriene receptor antagonists (LRA) or only with intranasal steroids (INS). Results: During two years, 501 subjects were included: 234 control subjects and 267 patients with PER. The levels of nasal NO, total IgE, blood eosinophil counts, and apnea-hypopnea index (AHI) in patients with PER were higher than controls (P < 0.001; P < 0.05; P < 0.05; P < 0.01; respectively). There were statistically significant correlations between nasal NO, nasal peak flows, total IgE, and blood eosinophil counts in patients with PER (R = -0.687 and P = 0.0012; R = -0.643 and P = 0.0018; R = 0.432 and P = 0.0024; R = 0.445 and P = 0.002; respectively). After 6 months of treatment, patients treated with INS had greater improvement of clinical symptoms and reduction of nasal NO values than patients treated with ATH + LRA (985 +/- 253 vs. 732 +/- 298 ppb; P < 0.05). Conclusion: Nasal NO measurement is a useful tool for the follow-up of patients with PER. It also helps clinicians to estimate the level of response to treatment in patients with PER.