Allergy Testing for Horses

The clinical signs of allergies in horses can vary depending on the type of allergen and how the body reacts. Because these symptoms overlap with other conditions, accurate diagnosis is essential — and that’s where allergy testing becomes a valuable tool.

How Are Allergies Diagnosed in Horses?

The diagnosis of allergies is clinical, based on your horse’s history, symptoms, and by excluding other potential causes. Once an allergy is suspected or confirmed, diagnostic testing, such as a blood test, is used to identify the specific allergens responsible for triggering the reaction. This information helps guide targeted management strategies, including allergen avoidance and immunotherapy (the only causal treatment and potential cure for allergies).

There are two primary diagnostic methods used in equine allergy medicine to identify the offending allergens:

1. Serological (Blood) Testing

This method analyzes a blood sample for allergen-specific IgE antibodies, which indicate sensitization to specific allergens. It’s less invasive, allows for testing while the horse remains on medication, and is ideal for detailed allergy profiling.

2. Intradermal (Skin) Testing

This involves injecting small amounts of allergens under the horse's skin and observing reactions. It’s effective but can be influenced by medications, requires sedation, and must be performed under controlled conditions.

What Is PAX – Horse Allergy Xplorer?

PAX – Horse Allergy Xplorer is a molecular-based allergy blood test designed specifically for horses. It uses component-resolved diagnostics, which means it doesn’t just test for broad allergen extracts – it identifies specific molecular components (proteins) that are the true responsible for triggering the immune response in allergic horses.

The test measures IgE antibodies in the blood, which indicate sensitization to particular allergens. With a panel covering over 200 allergen components, including pollens, molds, mites, and insect proteins, PAX offers a comprehensive and highly specific allergy profile.

This allows veterinarians to:

Identify the individual allergens a horse is sensitized to

Understand cross-reactivity between allergens (e.g., similar proteins in different species of pollen or insects)

Support a more tailored allergy management strategy, including allergen avoidance and immunotherapy

PAX offers a more precise and comprehensive overview of what your horse is allergic to, empowering vets to make targeted, evidence-based decisions.

When to Consider Allergy Testing for Your Horse

Your veterinarian may recommend allergy testing if your horse:

Experiences recurring skin or respiratory symptoms

Shows seasonal patterns of discomfort

Reacts to insect bites or environmental changes

Has been unresponsive to traditional treatments

Needs a long-term allergy management or desensitization plan

Early diagnosis can help avoid prolonged discomfort, prevent complications, and support your horse’s overall wellbeing and performance.

What Happens After the Test?

Once the PAX results are returned, your vet can:

Identify specific allergens and explain potential environmental or dietary adjustments

Discuss options like allergen-specific immunotherapy (custom-made allergy vaccine)

Adjust treatment and management strategies based on your horse’s unique allergy profile

Monitor progress and adapt the plan over time

This personalized approach helps reduce trial-and-error treatments and increases the chances of long-term relief.

Allergies can quietly impact your horse’s comfort, health, and performance. With modern testing tools like PAX – Horse Allergy Xplorer, you and your vet can take a more informed approach—moving from symptom management to long-term, root-cause care.