Intradermal testing of horses with chronic obstructive pulmonary disease and recurrent urticaria.

The research investigates the skin reactivity to a variety of allergens in horses suffering from Chronic Obstructive Pulmonary Disease (COPD) and recurrent urticaria, comparing their responses to those of clinically healthy horses. The study found all tested horses, regardless of their health status, showed some positive test reactions, yet those with COPD or urticaria exhibited a higher percentage of allergen reactions than the healthy ones.

Methodology

• The study involved 6 horses with Chronic Obstructive Pulmonary Disease (COPD) and 8 horses with urticaria, all of whom were subjected to intradermal skin testing with 67 extracts derived from 58 different allergens. These allergens comprised of components from pollens, epidermals, cultivated farm plants, dusts, molds, and insects.
• The reactions of these horses were examined three times over a 24-hour period, immediately following the injections of allergenic extracts.
• The outcomes from these tests were then compared to those acquired from a group of 11 clinically normal horses, which served as controls.

Findings and Analysis

• All horses registered positive skin test reactions to some allergenic extracts. However, significant differences were notable between the reaction percentages of horses with COPD and normal horses, as well as between horses with urticaria and normal horses. Only 3.0% and 4.5% of the possible extract reactions respectively were significantly different.
• It was observed that horses with COPD or urticaria showed a greater total percentage of extract reactions compared to the clinically normal horses. This suggests that these illnesses may increase a horse’s sensitivity to allergens.
• Positive reactions were seen at all three evaluation moments, suggesting that reactions could occur at any stage post exposure. In addition, late-onset reactions were not consistently preceded by a positive reaction at earlier timeframes, hinting that the timing of allergic reactions may not be predictable or consistent.
• All tested horses with either COPD or urticaria exhibited at least one skin test reaction that surpassed the mean +/- 2 standard deviation, based on each of the 67 extracts’ evaluations within the group of clinically normal horses. This might indicate a heightened sensitivity or allergic response in horses with these conditions compared to their healthy counterparts.