Microneedles in Allergy Immunotherapy: the Present and Future.

Purpose of review: This review highlights current limitations of allergen-specific immunotherapy (AIT) methods and introduces microneedles (MNs) as an innovative transdermal platform to enhance AIT safety, efficacy, and patient adherence.

Recent findings: Conventional approaches such as Subcutaneous immunotherapy (SCIT), Sublingual immunotherapy (SLIT), and Oral immunotherapy (OIT) have shown clinical effectiveness but face challenges including systemic adverse reactions, prolonged treatment durations, poor adherence. Meanwhile, Epidermal allergen-specific immunotherapy (EPIT) and other skin-targeted AIT approaches is constrained by the limited epidermal penetration of allergens. Recent preclinical studies demonstrate that MN-based transdermal immunotherapy (MN-TDIT) effectively delivers allergen directly into immune-rich dermal layers, significantly enhancing allergen-specific immune responses, inducing a regulatory T-cell response, modulating Th1/Th2 balance, and decreasing allergic inflammation in preclinical respiratory, skin, and food allergy models. MN-TDIT exhibits clear advantages over existing AIT strategies, including improved immunogenicity, fewer side effects, ease of administration, and potential for self-administration. Further research should focus on resolving formulation stability issues, optimizing controlled allergen release, and validating safety and efficacy in large-scale clinical trials, thus facilitating MNs as a transformative strategy for improving AIT outcomes.