The correlation between FeNO and nNO in allergic rhinitis and bronchial asthma

This study aimed to evaluate the correlation between fractional exhaled nitric oxide (FeNO) and nasal nitric oxide (nNO) in allergic rhinitis (AR) and patients with or without bronchial asthma (BA). A total of 90 patients who were diagnosed with persistent AR (AR group, n = 30), BA (BA group, n = 30), or allergic rhinitis with bronchial asthma (AR-BA) (AR-BA group, n = 30), were enrolled in this study, along with 30 healthy adult volunteers (control group, n = 30). The participants were further divided into 2 groups based on the results of a skin-prick test (SPT): a highly atopic group (SPT = 3+ and above) and a moderately atopic group (SPT = 2+ and below). All participants underwent FeNO and nNO measurement, an absolute blood eosinophil count, total serum immunoglobulin measurement, and horizontal baseline lung capacity determination. The results showed that the FeNO levels in the 3 observation groups were significantly higher than those in the control group (P < .01), and in the BA group they were significantly higher than in the AR-BA group (P < .01). The levels of nNO in both the AR group and the AR-BA group were higher than those in the control group and the BA group (P < .01), but there was no significant difference between the AR group and the AR-BA group (P > .05). The levels of nNO in the BA group were also significantly different from those in the control group (P < .01). FeNO and nNO are positively correlated with the degree of AR in patients with BA; therefore, nNO levels can be used as an inflammatory marker of AR in patients with BA. FeNO can also be used as an inflammatory marker of AR in patients complicated with BA as a warning indicator of asthma.