Correlation of atopy and FeNO in allergic rhinitis: an Indian study.

BACKGROUND: Fractional exhaled nitric oxide (FeNO) is a non-invasive marker of airway inflammation. Limited published data are available on the effect of atopy on FeNO in allergic rhinitis.

OBJECTIVES: To investigate the relationship between atopy and FeNO in patients with allergic rhinitis.

METHODS: Patients with allergic rhinitis were assessed for atopy and exhaled breath analysis of nitric oxide. Atopy was assessed by skin prick testing (SPT) against 58 common aero-allergens; a wheal size of 3mm or more as compared to buffer saline was considered positive. Patients were labelled to be atopic if they had at least one positive SPT result. The measurement of FeNO level was done by using NIOX chemiluminescence analyser.

RESULTS: Forty-nine participants (26 males) aged between 8-50 years were studied and 31 of them were found to be atopic. The average value of FeNO in the subjects studied (n = 49) was 26.0 +/- 22.7 parts per billion (ppb) with significantly higher values being observed in atopic group as compared to non-atopic group (34.2 +/- 24.3 versus 11.9 +/- 9.0 ppb; p < 0.05).

CONCLUSION: As FeNO is a marker of lower airway inflammation, significantly higher FeNO levels in atopic allergic rhinitis patients suggest that it may be a predictor for onset of asthma in these patients.