First report of angio-oedema subsequent to the administration of allergen specific sublingual immunotherapy for the management of equine hypersensitivity dermatitis.

This research article discusses a case where a horse experienced adverse reactions after being treated with Sublingual Immunotherapy (SLIT) for hypersensitivity dermatitis, marking the first documented incident of this kind.

Introduction and Objective

• This study examines the first known case of multiple adverse reactions in a horse following repeated administration of Sublingual Immunotherapy (SLIT).
• SLIT, an alternative to subcutaneous immunotherapy (SCIT), is used to induce immunological tolerance by providing allergen delivery beneath the tongue.
• Up until this particular case, there had not been any documented accounts regarding the efficacy or safety of SLIT usage in horses.

Methods and Case Details

• The subject of analysis was a seven-year-old warmblood mare diagnosed with equine hypersensitivity dermatitis (EHD), an allergic skin condition in horses.
• On advice of the medical professionals, the horse’s owner agreed to SLIT treatment in response to the horse’s temperament.

Results

• Unfortunate adverse reactions started to occur 36 hours after the mare began the SLIT treatment, which included scleral (of the eye) oedema, difficulty breathing, and abdominal discomfort.
• After a 10-day break from the therapy, the horse was re-exposed to a ten-fold diluted dose of the original vaccine; however, the mare displayed localized oedema and tongue swelling within 12 hours of the lower dose.
• At this point, SLIT was discontinued completely and the horse was tested with the allergen vehicle used for SLIT, 50% glycerine, with no adverse reactions observed.
• The same allergens were then administered via SCIT format, which led to no adverse events, despite repeated doses.

Conclusions

• This research marks the first known account of adverse reactions in a horse following the administration of SLIT for managing EHD.
• This finding brings into question the safety and efficacy of SLIT for managing EHD in horses and emphasizes the need for further research in this domain.