Determination of irritant threshold concentrations of multiple tree, grass, weed and mould allergens for intradermal testing of horses residing in the southern USA.

The research article presents a study aimed at determining the threshold concentrations of various tree, grass, weed and mould allergens for testing potential allergic reactions in horses based in the southern United States. The findings establish threshold concentrations for multiple allergens, thus helping towards fine-tuning intradermal allergen concentrations for testing purposes.

Study Overview

• This research aims to establish the threshold concentrations (TCs) of multiple tree, grass, weed, and mould allergens in horses residing in the southern United States through intradermal testing (IDT).
• The study involved 24 clinically normal horses. The allergen threshold concentrations were determined using IDT subjective measurements at 30 minutes.
• Late phase reactions were evaluated at 4 and 24 hours after the injection of allergens.

Results

• The findings provided threshold concentrations for eight tree allergens, two grass allergens, two weeds, and one mould.
• For some allergens like Bahia and perennial rye grass, the threshold concentration couldn’t be determined due to excessive reactivity at the lowest tested concentration.
• Eleven other allergens didn’t meet the criteria to establish a threshold concentration due to a lack of positive reactions when evaluated at 30 minutes after injection.
• Several allergens caused positive reactions in more than 10% of the horses after 4 hours, while reactions at 24 hours were rare, with one exception.

Conclusions

• The study successfully identified intradermal threshold concentrations for multiple pollen and mould allergens in horses.
• These values may be beneficial for optimizing allergen concentrations for intradermal testing of allergic horses, improving diagnostic accuracy and treatment planning.