Intradermal Testing Results in Horses Affected by Mild-Moderate and Severe Equine Asthma.
Authors: Lo Feudo Chiara Maria, Stucchi Luca, Alberti Elena, Conturba Bianca, Zucca Enrica, Ferrucci Francesco
Journal: Animals : an open access journal from MDPI
Summary
# Editorial Summary: Intradermal Testing in Equine Asthma Allergic mechanisms are believed central to equine asthma pathogenesis, yet intradermal testing (IDT) has yielded contradictory results in asthmatic populations. This Italian study examined IDT responses in 38 horses with mild-moderate asthma (MEA) and severe asthma (SEA) using 50 allergens, measuring skin reactions at 30 minutes, 4, 24 and 48 hours post-injection on a 0–4 scoring scale. Severe asthma cases demonstrated predominantly early reactions (30 min–4 hours), indicative of type I (IgE-mediated) hypersensitivity, whilst mild-moderate cases showed a mixed pattern suggesting concurrent type IV (cell-mediated) involvement. Across both disease severities, insects, *Dermatophagoides* mites and dog epithelium provoked the strongest and most consistent reactions, emerging as primary allergenic triggers in this geographic region. These findings suggest that IDT response patterns may differ meaningfully between asthma phenotypes, and that identifying region-specific allergen profiles could inform targeted environmental management strategies—particularly housing design and bedding selection—as adjuncts to medical management in asthmatic horses.
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Practical Takeaways
- •Intradermal testing can differentiate hypersensitivity mechanisms between mild-moderate and severe equine asthma, guiding tailored allergen avoidance strategies
- •For SEA horses, focus on early reactions (30 min to 4 h) during IDT interpretation; for MEA horses, monitor extended time points to capture delayed-type responses
- •Prioritize environmental control of insects, dust mites (Dermatophagoides), and minimize dog contact in stables as these are the most clinically significant allergens in equine asthma cases
Key Findings
- •SEA horses showed strongest intradermal test reactions at 30 min and 4 h, indicating type I hypersensitivity predominance
- •MEA horses demonstrated reactions across multiple time points (30 min to 48 h), suggesting both type I and type IV hypersensitivity involvement
- •Insects, Dermatophagoides spp., and dog epithelium were the most significant allergens triggering hypersensitivity in both MEA and SEA horses
- •IDT timing of evaluation (30 min, 4, 24, and 48 h) is critical for accurately identifying hypersensitivity mechanisms in asthmatic horses