Nasal nitric oxide in the inferior turbinate surface decreases with intranasal steroids in allergic rhinitis: A prospective study.

OBJECTIVE: It remains controversial whether nasal nitric oxide (NO) serves as a reliable parameter to evaluate treatment efficacy in patients with allergic rhinitis (AR). The measurement of local nasal NO levels has been shown to be a sensitive marker for the diagnosis of symptomatic AR patients. Here we assessed the applicability of nasal NO to evaluations of the efficacy of intranasal steroids (INS) in a prospective design.

METHODS: We enrolled 25 patients with perennial AR and 10 age-matched healthy participants. The AR patients received fluticasone furoate (FF) once daily for 2 months. Fractional exhaled NO and nasal NO measurements were carried out using an electrochemical analyzer at pretreatment and at 2 weeks and 2 months after treatment. Nasal NO levels were directly measured at two different areas of the nasal cavity: the surface of the inferior turbinate (IT area) and the front of the middle meatus (MM area). Subjective nasal symptoms were also recorded at each visit.

RESULTS: The mean total nasal symptom score in the AR patients decreased significantly after FF treatment (p<0.0001). The mean nasal NO levels in the IT area in the AR patients were significantly higher at pretreatment than those of the healthy participants (109 vs. 62.5 ppb, respectively; p<0.001). After FF administration, the nasal NO levels in the IT area of the AR group showed a significant reduction at both 2 weeks and 2 months (79.1 and 71.9 ppb, respectively; p<0.05 and p<0.01). There was no significant difference in nasal NO levels in the MM area between the controls and the AR group at any visit timepoint. When the ratio of the MM area to the IT area (MM/IT ratio) was plotted for each subject, the untreated AR patients showed a marked decrease in the ratio, whereas after the FF treatment, the AR patients' mean MM/IT ratios showed a significant increase. No significant difference compared to the control group existed at 2 months.

CONCLUSION: Nasal NO measurement around the inferior turbinate is an objective measure to evaluate allergic conditions and is useful to monitor therapeutic effects of INS.