Vet Tips 2025: Allergy Testing in Horses With Asthma—What Horse Owners Should Know 🐎🌾

By Dr Duncan Houston BVSc

Equine asthma—formerly known as heaves or COPD—is one of the most common chronic respiratory conditions affecting adult horses. But despite our increasing understanding of the disease, there’s still confusion around how best to diagnose and manage it—especially when it comes to allergy testing. 🧠🌬️

What Is Equine Asthma? 🐴💨

Equine asthma is a non-infectious respiratory condition caused by a hypersensitive reaction in the airways, similar to allergic asthma in humans. It is typically triggered by:

• 🌿 Organic dust from hay and bedding
• 💨 Mold spores and plant debris
• 🦠 Bacterial endotoxins
• 🕷️ Mites in feed and stable dust
• 💧 High levels of ammonia in stalls

These allergens trigger airway inflammation, excess mucus production, coughing, and labored breathing. Horses housed indoors or exposed to poor ventilation are at higher risk. 🏠

The Role of Allergy Testing 🧪❓

In human and companion animal medicine, allergy testing is sometimes used to identify triggers and develop desensitization therapies. The same idea has been explored in equine medicine, with the goal of creating individualized allergy vaccines (also known as immunotherapy). 💉

The Research 🔍

Veterinary researchers in Germany evaluated the effectiveness of allergy testing in horses with asthma by using four types of allergy diagnostics on 15 horses:

• ✅ Six healthy horses (no respiratory disease)
• 🌬️ Nine horses diagnosed with equine asthma

They performed:

• 💉 Serum (blood) allergy testing
• 🩹 Intradermal (skin) testing
• 🌬️ Inhalant exposure tests
• 🧫 Specialized cellular reactivity assessments

Unfortunately, the results were disappointing. There was no consistency among the tests. Positive results on one test were often negative on others, and even horses without asthma had multiple “positive” responses. 🧪🚫

What This Means for Horse Owners 🧠🏇

Although the idea of pinpointing allergens to build custom therapies is appealing, current science shows that:

• 📉 Skin testing may reflect surface-level skin sensitivities—not internal respiratory allergies
• ❌ There is no “gold standard” test with reliable consistency
• 🔁 Positive tests are frequently seen in healthy horses with no respiratory symptoms

This means that allergy testing, in its current form, is unlikely to be a reliable diagnostic tool for equine asthma. ⚠️

Why Not Just Try It Anyway? 💭

When test results are unclear or inconsistent, it’s hard to know which allergens to target in desensitization therapy. Owners may end up:

• 💸 Spending significant money on testing and custom vaccines
• 🕰️ Delaying more effective environmental or medical management
• 📉 Failing to improve the horse’s symptoms despite treatment

What You Can Do Instead 🛠️🐴

Managing equine asthma starts with controlling the horse’s environment and minimizing exposure to common irritants:

• 🌾 Soak or steam hay to reduce dust and mold spores
• 🏠 Increase stall ventilation
• 🚫 Remove dusty bedding—use low-dust shavings or paper bedding
• 🌬️ Avoid sweeping or working horses during high dust times

Medical treatment may also be recommended by your veterinarian:

• 💊 Corticosteroids to reduce airway inflammation
• 💨 Bronchodilators to open airways during flare-ups
• 🧪 Nebulized medications for targeted relief

When Allergy Testing Might Be Considered 🤔

Despite its limitations, allergy testing may still be considered in specialized cases, particularly when:

• 🐎 A horse has multiple chronic allergic symptoms (respiratory and dermatologic)
• 🧬 Immunotherapy is being considered under close veterinary supervision
• 📉 All environmental control strategies have failed

But results should be interpreted cautiously—and always in combination with a full clinical evaluation. 🧠

Need Help Managing Your Horse’s Asthma? Ask A Vet 🐴📱

If you're dealing with a coughing or wheezing horse and unsure where to start, connect with a veterinarian via Ask A Vet. We offer guidance on respiratory support, allergy management, and realistic treatment plans for equine asthma. 💬

Download the Ask A Vet app today for expert equine advice—anytime, anywhere. 🐴💙

Final Thoughts: Focus on What Works 🧠🌿

While allergy testing may seem like the logical next step in asthma management, the science just doesn’t support it—for now. Instead, prioritize proven strategies like:

• 🧼 Dust reduction
• 🌬️ Ventilation
• 💊 Appropriate medication

Need help creating an asthma-friendly plan for your horse? Visit Ask A Vet—we’re here to help every breath of the way. 🐴💨