Nonallergic Rhinopathy: A Comprehensive Review of Classification, Diagnosis, and Treatment

Chronic nonallergic rhinitis syndromes encompass various conditions, of which vasomotor rhinitis is the most common form, representing approximately 80% of patients, also referred to as nonallergic rhinopathy (NAR), nasal hyperreactivity, neurogenic rhinitis, or idiopathic rhinitis. Expert panels have recommended replacing vasomotor rhinitis terminology because it is more descriptive of this condition that is characterized by symptoms triggered by chemical irritants and weather changes through chemosensors, mechanosensors, thermosensors, and/or osmosensors activated through different transient receptor potential calcium ion channels. Elucidating the specific role of transient receptor potential vanilloid 1, triggered by capsaicin, has been an important advancement in better understanding the pathophysiology of NAR because it has now been shown that downregulation of transient receptor potential vanilloid 1 receptors by several therapeutic compounds provides symptomatic relief for this condition. The classification of NAR is further complicated by its association with allergic rhinitis referred to as mixed rhinitis, which involves both immunoglobulin E-mediated and neurogenic mechanistic pathways. Comorbidities associated with NAR, including rhinosinusitis, headaches, asthma, chronic cough, and sleep disturbances, underscore the need for comprehensive management. Treatment options for NAR include environmental interventions, pharmacotherapy, and in refractory cases, surgical options, emphasizing the need for a tailored approach for each patient. Thus, it is extremely important to accurately diagnose NAR because inappropriate therapies lead to poor clinical outcomes and unnecessary health care and economic burdens for these patients. This review provides a comprehensive overview of NAR subtypes, focusing on classification, diagnosis, and treatment approaches for NAR.

International consensus statement on allergy and rhinology: Allergic rhinitis - 2023

BACKGROUND

In the 5 years that have passed since the publication of the 2018 International Consensus Statement on Allergy and Rhinology: Allergic Rhinitis (ICAR-Allergic Rhinitis 2018), the literature has expanded substantially. The ICAR-Allergic Rhinitis 2023 update presents 144 individual topics on allergic rhinitis (AR), expanded by over 40 topics from the 2018 document. Originally presented topics from 2018 have also been reviewed and updated. The executive summary highlights key evidence-based findings and recommendation from the full document.

METHODS

ICAR-Allergic Rhinitis 2023 employed established evidence-based review with recommendation (EBRR) methodology to individually evaluate each topic. Stepwise iterative peer review and consensus was performed for each topic. The final document was then collated and includes the results of this work.

RESULTS

ICAR-Allergic Rhinitis 2023 includes 10 major content areas and 144 individual topics related to AR. For a substantial proportion of topics included, an aggregate grade of evidence is presented, which is determined by collating the levels of evidence for each available study identified in the literature. For topics in which a diagnostic or therapeutic intervention is considered, a recommendation summary is presented, which considers the aggregate grade of evidence, benefit, harm, and cost.

CONCLUSION

The ICAR-Allergic Rhinitis 2023 update provides a comprehensive evaluation of AR and the currently available evidence. It is this evidence that contributes to our current knowledge base and recommendations for patient evaluation and treatment.

Rhinitis 2020: A practice parameter update

This comprehensive practice parameter for allergic rhinitis (AR) and nonallergic rhinitis (NAR) provides updated guidance on diagnosis, assessment, selection of monotherapy and combination pharmacologic options, and allergen immunotherapy for AR. Newer information about local AR is reviewed. Cough is emphasized as a common symptom in both AR and NAR. Food allergy testing is not recommended in the routine evaluation of rhinitis. Intranasal corticosteroids (INCS) remain the preferred monotherapy for persistent AR, but additional studies support the additive benefit of combination treatment with INCS and intranasal antihistamines in both AR and NAR. Either intranasal antihistamines or INCS may be offered as first-line monotherapy for NAR. Montelukast should only be used for AR if there has been an inadequate response or intolerance to alternative therapies. Depot parenteral corticosteroids are not recommended for treatment of AR due to potential risks. While intranasal decongestants generally should be limited to short-term use to prevent rebound congestion, in limited circumstances, patients receiving regimens that include an INCS may be offered, in addition, an intranasal decongestant for up to 4 weeks. Neither acupuncture nor herbal products have adequate studies to support their use for AR. Oral decongestants should be avoided during the first trimester of pregnancy. Recommendations for use of subcutaneous and sublingual tablet allergen immunotherapy in AR are provided. Algorithms based on a combination of evidence and expert opinion are provided to guide in the selection of pharmacologic options for intermittent and persistent AR and NAR.

Intranasal corticosteroids for non-allergic rhinitis

BACKGROUND

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.

OBJECTIVES

To assess the effects of intranasal corticosteroids in the management of non-allergic rhinitis.

SEARCH METHODS

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.

SELECTION CRITERIA

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).

DATA COLLECTION AND ANALYSIS

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.

MAIN RESULTS

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.

AUTHORS' CONCLUSIONS

Overall, the certainty of the evidence for most outcomes in this review was low or very low. It is unclear whether intranasal corticosteroids reduce patient-reported disease severity in non-allergic rhinitis patients compared with placebo when measured at up to three months. However, intranasal corticosteroids probably have a higher risk of the adverse effect epistaxis. There are very few studies comparing intranasal corticosteroids to other treatment modalities making it difficult to draw conclusions.