Mometasone furoate nasal spray improves olfactory performance in seasonal allergic rhinitis.

Abstract

Impairment of olfactory function is frequently present in patients with allergic rhinitis (1, 2). This seems to be associated particularly with inflammatory processes (3). The aim of this study was to investigate the effects of mometasone furoate nasal spray on olfactory performance in patients with seasonal allergic rhinitis. Twenty-four patients (age 27.3 4.9 years) took part in this double-blind, placebo-controlled, randomized, prospective study (11 placebo, 13 verum). Allergic rhinitis was diagnosed on the basis of a medical history and skin prick tests. Allergy symptoms were quantitatively assessed before and after treatment. Nasal airflow was measured with anterior rhinomanometry. Psychophysical measures of olfactory function were obtained using the ‘Sniffin’ Sticks’ test kit (Heinrich Burghart Elektround Feinmechanik GmbH, Wedel, Germany; bilateral testing of butanol odor threshold, odor discrimination and identification) (4). Patients received mometasone furoate nasal spray (Nasonex, Essex Pharma GmbH, Munchen, Germany) or placebo for 2 weeks. The results were normalized to baseline values. SPSS software (v. 10) was used for statistical analyses. After testing for normal distribution, investigations were performed with the help of variance analyses for repeated measures; nasal air-flow was used as a co-variate. t-tests were employed for between-group analyses and for posthoc comparisons. For correlational analyses, Pearson statistics were used. Symptom scores were reduced in both groups (placebo: 24.7 12.9 to 20.4 14.8 units, mometasone 18.4 13.1 to 8.8 7.6 units; t 1⁄4 0.85, P 1⁄4 0.41). Nasal flow decreased in the placebo group (731 122 to 688 145 cm/s) and increased in the mometasone group (747 177 to 805 93 cm/s). However differences between groups were not significant (t 1⁄4 1.79, P 1⁄4 0.08). When investigating olfactory function, the main effect for the factor ‘treatment’ narrowly missed statistical significance (F [1,21] 1⁄4 3.75, P 1⁄4 0.066). However, there was a significant interaction between the factors ‘test’ and ‘treatment’ (F [2,42] 1⁄4 3.93, P 1⁄4 0.027) indicating that test results differed between groups. Posthoc comparisons revealed that mometasone subjects became more sensitive to butanol than subjects treated with placebo (t 1⁄4 2.22, P 1⁄4 0.037) while there was no such difference for odor identification (t 1⁄4 1.41, P 1⁄4 0.17) or odor discrimination (t 1⁄4 0.92, P 1⁄4 0.37). There was a nonsignificant correlation between normalized air-flow and normalized results of olfactory tests: r24 0.55. Odor threshold significantly improved after 2 weeks of treatment with mometasone furoate nasal spray. This appeared to be independent of the accompanying improvement in allergic symptoms or nasal airflow. This supports the notion that impairment of olfactory function in allergic rhinitis is mostly because of the allergic inflammation and not because of reduced nasal airflow alone. Following topical treatment with steroids, Meltzer et al. (5) reported significant improvement of odor identification, but not of odor thresholds. As they used the Connecticut Chemosensory Clinical Research Center evaluation, differences may relate to different methods of assessing odor threshold. In conclusion, anti-inflammatory treatment with topical nasal steroids not only reduces ‘classical’ symptoms of allergy but improves olfactory function in patients with seasonal allergic rhinitis.