Use of Nasal Nitric Oxide in the Diagnosis of Allergic Rhinitis and Nonallergic Rhinitis in Patients with and without Sinus Inflammation

Abstract Background Nasal NO (nNO) has been evaluated in patients with chronic rhinosinusitis with and without nasal polyps. However, nNO levels in patients with allergic rhinitis (AR) and nonallergic rhinitis (NAR) have shown conflicting results in previous studies. Objective This study aimed to evaluate the value of nNO in diagnosing AR and NAR and the impact of absence or presence of sinus inflammation. Methods A total of 173 consecutive patients scanned with high-resolution CT and 46 normal controls (NCs) were included in our study. Patients were evaluated according to their medical history, nasal symptoms, endoscopic examination and skin prick test. Based on CT scan (Lund-Mackey score >2), all patients were subgrouped as AR with (ARwSI) and without (ARsSI) sinus inflammation, or NAR with (ARwSI) and without (NARsSI) sinus inflammation. nNO levels were measured with NOIX device and eosinophils in nasal smears were evaluated simultaneously. ROC analysis was performed for differential diagnosis of AR, NAR and subgroups. Results Ninety-four patients were diagnosed as AR and 79 patients as NAR. The levels of nNO were significantly higher in both patients with AR and NCs compared with patients with NAR (939±335 in AR and 813±272 in NCs vs 670±188 in NAR; P Conclusions nNO levels are different between AR and NAR with/without sinus inflammation, and may be utilized to discriminate these phenotypes.