Nasal and Exhaled Nitric Oxide in Allergic Rhinitis

OBJECTIVES The primary aim of this study was to assess whether one can use levels of nasal nitric oxide (nNO) and exhaled nitric oxide (eNO) as a means of evaluation in allergic rhinitis. METHODS We used a chemiluminescence analyzer to measure nNO and eNO in normal controls (n=34) and allergic rhinitis patients (n=35), and compared these measurements with various parameters of clinical symptoms and laboratory data. RESULTS Mean nNO (389±119 ppb) in allergic rhinitis patients was significantly higher than normal controls (276±88 ppb). Without asthma, mean eNO (64.8±55.9 ppb) in allergic rhinitis patients was significantly higher than normal controls (33.0±24.0 ppb). In the persistent allergic rhinitis group, eNO concentration was significantly higher, while nNO concentration was significantly lower than the intermittent group. CONCLUSION We can use nNO and eNO levels for evaluation of allergic rhinitis. However, we should consider the fact that nNO levels can be reduced, when symptoms are severe and long-lasting. Additionally, in allergic rhinitis, eNO can be elevated without asthma.