Does allergen immunotherapy for allergic rhinitis prevent asthma?

Asthma and allergic rhinitis (AR) have overlapping clinical and pathologic features, sustained by an underlying T helper 2 bias, resulting in airway inflammation that extends from the nose to the lung. Children who are mono -sensitized often develop polysensitization over time, and they are at high risk of developing asthma. The effect of allergen immunotherapy (AIT) is allergen specific, resulting in symptom improvement and reduction in medi-cation requirement. It is the only known treatment that alters the natural history of allergic disease and induces long-term remission. A bystander or allergen-nonspecific effect of AIT has also been proposed-that AIT to 1 allergen might reduce the risk of development of sensitization to other allergens. Furthermore, several observa-tional studies and clinical trials, in seasonal (pollen) and perennial (house dust mite) AR, have investigated a pro-tective effect of AIT to prevent asthma. The overall evidence favors an asthma preventive effect of AIT in AR to grass and birch tree pollen. Fewer studies have investigated the use of AIT in children with perennial AR due to house dust mite allergy to prevent asthma, and the results are less convincing. The use of AIT to reduce the risk of progression to asthma, in children with AR, potentially has high impact, and it will make AIT more attractive and cost-effective. However, most studies have been of small sample size or of poor design, using different aller-gens and AIT methodology, making it challenging to draw firm conclusions. There is a need to do adequately powered studies with optimal design and assess cost-effectiveness of this strategy.(c) 2022 American College of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

Automated summary

Asthma and allergic rhinitis share similar features and can be treated with allergen immunotherapy (AIT) to improve symptoms and reduce medication usage. AIT is the only known treatment that can modify the natural course of allergic disease and induce long-term remission. However, more research is needed to determine the effectiveness of AIT in preventing asthma, and studies with larger sample sizes and cost-effectiveness evaluations are necessary.