Non-allergic rhinitis is defined as dysfunction and non-infectious inflammation of the nasal mucosa that is caused by provoking agents other than allergens or microbes. It is common, with an estimated prevalence of around 10% to 20%. Patients experience symptoms of nasal obstruction, anterior rhinorrhoea/post-nasal drip and sneezing. Several subgroups of non-allergic rhinitis can be distinguished, depending on the trigger responsible for symptoms; these include occupation, cigarette smoke, hormones, medication, food and age. On a cellular molecular level different disease mechanisms can also be identified. People with non-allergic rhinitis often lack an effective treatment as a result of poor understanding and lack of recognition of the underlying disease mechanism. Intranasal corticosteroids are one of the most common types of medication prescribed in patients with rhinitis or rhinosinusitis symptoms, including those with non-allergic rhinitis. However, it is unclear whether intranasal corticosteroids are truly effective in these patients.
To assess the effects of intranasal corticosteroids in the management of non-allergic rhinitis.
The Cochrane ENT Information Specialist searched the Cochrane ENT Register; Cochrane Central Register of Controlled Trials (CENTRAL 2019, Issue 7); PubMed; Ovid Embase; CINAHL; Web of Science; ClinicalTrials.gov; ICTRP and additional sources for published and unpublished trials. The date of the search was 1 July 2019.
Randomised controlled trials (RCTs) comparing intranasal corticosteroids, delivered by any means and in any volume, with (a) placebo/no intervention or (b) other active treatments in adults and children (aged ≥ 12 years).
We used the standard methodological procedures expected by Cochrane. The primary outcomes were patient-reported disease severity and a significant adverse effect - epistaxis. Secondary outcomes were (disease-specific) health-related quality of life, objective measurements of airflow and other adverse events. We used GRADE to assess the certainty of the evidence for each outcome.
We included 34 studies (4452 participants); however, only 13 studies provided data for our main comparison, intranasal corticosteroids versus placebo. The participants were mainly defined as patients with perennial rhinitis symptoms and negative allergy tests. No distinction between different pheno- and endotypes could be made, although a few studies only included a specific phenotype such as pregnancy rhinitis, vasomotor rhinitis, rhinitis medicamentosa or senile rhinitis. Most studies were conducted in a secondary or tertiary healthcare setting. No studies reported outcomes beyond three months follow-up. Intranasal corticosteroid dosage in the review ranged from 50 µg to 2000 µg daily. Intranasal corticosteroids versus placebo Thirteen studies (2045 participants) provided data for this comparison. These studies used different scoring systems for patient-reported disease severity, so we pooled the data in each analysis using the standardised mean difference (SMD). Intranasal corticosteroid treatment may improve patient-reported disease severity as measured by total nasal symptom score compared with placebo at up to four weeks (SMD -0.74, 95% confidence interval (CI) -1.15 to -0.33; 4 studies; 131 participants; I2 = 22%) (low-certainty evidence). However, between four weeks and three months the evidence is very uncertain (SMD -0.24, 95% CI -0.67 to 0.20; 3 studies; 85 participants; I2 = 0%) (very low-certainty evidence). Intranasal corticosteroid treatment may slightly improve patient-reported disease severity as measured by total nasal symptom score change from baseline when compared with placebo at up to four weeks (SMD -0.15, 95% CI -0.25 to -0.05; 4 studies; 1465 participants; I2 = 35%) (low-certainty evidence). All four studies evaluating the risk of epistaxis showed that there is probably a higher risk in the intranasal corticosteroids group (65 per 1000) compared to placebo (31 per 1000) (risk ratio (RR) 2.10, 95% CI 1.24 to 3.57; 4 studies; 1174 participants; I2 = 0%) (moderate-certainty evidence). The absolute risk difference (RD) was 0.04 with a number needed to treat for an additional harmful outcome (NNTH) of 25 (95% CI 16.7 to 100). Only one study reported numerical data for quality of life. It did report a higher quality of life score in the intranasal corticosteroids group (152.3 versus 145.6; SF-12v2 range 0 to 800); however, this disappeared at longer-term follow-up (148.4 versus 145.6) (low-certainty evidence). Only two studies provided data for the outcome objective measurements of airflow. These data could not be pooled because they used different methods of outcome measurement. Neither found a significant difference between the intranasal corticosteroids and placebo group (rhinomanometry SMD -0.46, 95% CI -1.06 to 0.14; 44 participants; peak expiratory flow rate SMD 0.78, 95% CI -0.47 to 2.03; 11 participants) (very low-certainty evidence). Intranasal corticosteroids probably resulted in little or no difference in the risk of other adverse events compared to placebo (RR 0.99, 95% CI 0.87 to 1.12; 3 studies; 1130 participants; I2 = 0%) (moderate-certainty evidence). Intranasal corticosteroids versus other treatments Only one or a few studies assessed each of the other comparisons (intranasal corticosteroids versus saline irrigation, intranasal antihistamine, capsaicin, cromoglycate sodium, ipratropium bromide, intranasal corticosteroids combined with intranasal antihistamine, intranasal corticosteroids combined with intranasal antihistamine and intranasal corticosteroids with saline compared to saline alone). It is therefore uncertain whether there are differences between intranasal corticosteroids and other active treatments for any of the outcomes reported.