Intranasal Antihistamines and Corticosteroids Effective in Allergic Rhinitis, but Evidence Variability Remains: Review

The meta-analysis, published in the Journal of Allergy and Clinical Immunology found that most intranasal medications effectively alleviate rhinitis symptoms and enhance quality of life. However, there were notable variations in the reliability of the evidence supporting these treatments. 

Antihistamines and intranasal corticosteroids are primary treatments for allergic rhinitis (AR), with intranasal medications preferred due to their higher effectiveness and quicker action than oral treatments. However, most guidelines report a low level of evidence for these recommendations. There is a lack of consistent data on the effectiveness of specific intranasal medications, and randomized controlled trials vary in quality. A systematic review using standardized methods is needed to better assess their effectiveness. 

Against the above background, Bernardo Sousa-Pinto, Centre for Health Technology and Services Research, Health Research Network, Faculty of Medicine, University of Porto, Porto, Portugal, and colleagues aimed to conduct a systematic review to compare the efficacy of individual intranasal corticosteroids and antihistamines versus placebo in alleviating nasal and ocular symptoms, as well as improving rhinoconjunctivitis-related quality of life in patients with perennial or seasonal allergic rhinitis.

For this purpose, the researchers conducted a comprehensive search across four electronic bibliographic databases and three clinical trial databases to identify randomized controlled trials (1) involving adult patients with seasonal or perennial allergic rhinitis (AR) and (2) comparing the use of intranasal corticosteroids or antihistamines with placebo.

Outcomes assessed included the Total Nasal Symptom Score, Total Ocular Symptom Score, and the Rhinoconjunctivitis Quality-of-Life Questionnaire. Random-effects meta-analyses were performed to calculate mean differences for each medication and outcome. Evidence certainty was evaluated using the GRADE (Grading of Recommendations, Assessment, Development, and Evaluation) approach.

The following were the key findings of the study:

• The review included 151 primary studies, primarily assessing patients with seasonal allergic rhinitis majority having unclear or high risk of bias.
• In both perennial and seasonal AR, most treatments were more effective than placebo.
• In seasonal AR, azelastine-fluticasone, fluticasone furoate, and fluticasone propionate showed the highest likelihood of achieving moderate or large improvements in the Total Nasal Symptom Score and Rhinoconjunctivitis Quality-of-Life Questionnaire.
• Azelastine-fluticasone had the highest probability of leading to moderate or large improvements in the Total Ocular Symptom Score.
• Evidence certainty was categorized as “high” in 6 of 46 analyses, “moderate” in 23 of 46 analyses, and “low” or “very low” in 17 of 46 analyses.

In seasonal allergic rhinitis (SAR), all intranasal antihistamines and corticosteroids demonstrated effectiveness in improving nasal symptoms, both statistically and clinically. Most medications also led to significant improvements in the Rhinoconjunctivitis Quality-of-Life Questionnaire (RQLQ). However, there were notable differences between treatments concerning the likelihood of surpassing the Minimal Important Difference (MID).

"In perennial allergic rhinitis (PAR), the assessed medications were effective, but there was a lack of evidence for some drugs and outcomes. While evidence certainty for most outcomes was rated as "moderate," several limitations in the available data were identified. This systematic review provides valuable insights to guide future recommendations for intranasal medications in managing both PAR and SAR," the researchers concluded.

Reference:

Sousa-Pinto, B., Vieira, R. J., Brozek, J., Cardoso-Fernandes, A., Lourenço-Silva, N., Ferreira-da-Silva, R., Ferreira, A., Gil-Mata, S., Bedbrook, A., Klimek, L., Fonseca, J. A., Zuberbier, T., Schünemann, H. J., & Bousquet, J. (2024). Intranasal antihistamines and corticosteroids in allergic rhinitis: A systematic review and meta-analysis. Journal of Allergy and Clinical Immunology, 154(2), 340-354. https://doi.org/10.1016/j.jaci.2024.04.016