Does allergen immunotherapy for allergic rhinitis prevent asthma?

Arshad SH. Does allergen immunotherapy for allergic rhinitis prevent asthma? Ann Allergy Asthma Immunol. 2022 Sep;129(3):286-291. doi: 10.1016/j.anai.2022.04.028. 

Abstract

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 monosensitized 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 medication 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 observational studies and clinical trials, in seasonal (pollen) and perennial (house dust mite) AR, have investigated a protective 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 allergens 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.

Key Messages

•Allergic rhinitis and asthma are closely associated conditions, and children with allergic rhinitis often develop asthma over time.

•Allergen immunotherapy is the only known treatment that modifies the natural progression of allergic disease and induces long-term remission.

•Allergen immunotherapy to house dust mite and grass pollen might reduce the development of new sensitization to additional allergens, although robust evidence is lacking.

•Grass pollen allergen immunotherapy in children with seasonal allergic rhinitis prevents asthma symptoms.

•Further studies are required to investigate underlying mechanisms, study immunotherapy to other allergens such as house dust mite, and assess cost-effectiveness of this approach.

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