Efficacy and Safety of Subcutaneous Allergen-Specific Immuno-Therapy in Horses with Allergic Cutaneous and Respiratory Diseases-A Systematic Review

Simple Summary This study aimed to fill the gap in systematic reviews on the efficacy and safety of subcutaneous allergen-specific immunotherapy (AIT) in horses with allergic diseases. The review included horses with respiratory diseases, urticaria, and pruritic dermatitis treated with insect monotherapy or multi-allergen AIT. Beneficial effects were observed with multi-allergen AIT in respiratory diseases, urticaria, and pruritic dermatitis. However, when insect AIT was used solely for pruritic dermatitis, the response was less favorable. Overall, AIT demonstrated safety, with any adverse events generally being self-limiting. The review highlighted the presence of common biases and confounding factors in the included studies, warranting the need for more rigorous research.Abstract Allergen-specific immunotherapy (AIT) is the only current intervention that has the ability to modify the immune response toward a tolerogenic state. This study aimed to assess the efficacy and safety of AIT in horses with allergic diseases in a systematic manner. Three databases were searched to identify articles reporting clinical outcomes and adverse events associated with AIT. The articles were evaluated for beneficial responses to AIT, defined as a >= 50% reduction in clinical signs, and clinical remission. Horses with respiratory diseases, urticaria, and pruritic dermatitis receiving insect monotherapy or multi-allergen AIT were included. All adverse events were graded, and analytical and confounding biases were assessed. The results showed that multi-allergen AIT had a beneficial response in 75% of horses with respiratory diseases, 88% with urticaria, and 56% with pruritic dermatitis. However, horses treated solely with insect AIT for pruritic dermatitis had a lower response rate (36%). Self-limiting local reactions were the most common adverse events, with systemic reactions grade II accounting for 11% of reported events. Analytical and confounding biases were identified as major limitations in the available studies. Further research is needed to address these biases and provide stronger evidence on the efficacy and safety of AIT in horses with allergic diseases.

Automated summary

This study systematically evaluated the efficacy and safety of subcutaneous allergen-specific immunotherapy (AIT) in horses with allergic diseases. The results showed that multi-allergen AIT had beneficial effects in respiratory diseases, urticaria, and pruritic dermatitis. However, the response rate was lower when insect AIT was used solely for pruritic dermatitis. Overall, AIT was generally safe, with mostly self-limiting adverse events. The study highlighted the presence of biases and confounding factors in the included studies, calling for further research.