Efficacy of Sublingual Immunotherapy in the Treatment of House-Dust Mite Induced Allergic Rhinitis

Introduction: House-dust mite (HDM) induced allergic rhinitis (AR) is a chronic condition associated with rhinorrhea, nasal obstruction, nasal pruritus and sneezing. The current mainstay of treatment is intranasal corticosteroids, which have shown variable degrees of symptom control among patients. Chronic use is typically required to achieve continued relief. Immunotherapy works to increase peripheral immune tolerance by administration of the allergen itself. Not only does it have the potential to decrease acute symptoms of allergic rhinitis, but it is also the sole treatment offering disease-modifying potential with long-term use. Immunotherapy is an option which can eliminate both the chronic administration of medication and the economic burden of life-time purchasing of medication. Therefore, in order to determine the utility of immunotherapy in AR treatment, this review analyzes the use of sublingual immunotherapy for the treatment of HDM induced AR in comparison to a placebo. Methods: A literature search was conducted through PubMed and Clinical Key in April 2020. The search was modified to include only human clinical trials published in the past five years. A total of five articles relevant to the research question were selected for analysis. Results: The evidence compiled through five randomized controlled trials showed statistically significant symptom improvement in patients treated with SLIT in comparison to a placebo. Total combined rhinitis scores measured in three studies showed a reduction of greater than 15% in active groups. Total symptom scores showed a significant decrease in all studies analyzed. There were mixed significant and non-significant results in the measurement of medication scores after SLIT. Quality of life surveys showed improvement in active groups and the safety profile was favorable in all studies. Discussion: Overall, the study designs were similar in use of randomized double-blind placebo-controlled trials, which contributed to the validity of the studies. However, variable dosing and outcome measurements make comparison difficult and reveal the need for standardization in this field. Extension of the one-year duration of intervention should be considered to determine the long-term effects of SLIT. Conclusion: SLIT should be considered as an alternative or adjunct in the treatment of HDM-induced AR. SLIT has shown statistically significant symptomatic relief and a favorable safety profile. However, further research is required before SLIT can be recommended in place of the current standard of care. Cost-benefit analysis and more long-term studies are necessary for better assessment of where SLIT belongs on the treatment continuu