Food Allergy in Horses

Does your horse have itchy skin or digestive upset? While environmental allergies and insect bites are common culprits, food allergies in horses are an often-overlooked cause of chronic issues.

Though not as common as other allergies, food allergies can lead to skin flare-ups, gut trouble, and poor performance.

What Is a Food Allergy in Horses?

A food allergy is an abnormal immune reaction to certain proteins in your horse’s feed. Unlike food intolerances (which don’t involve the immune system), food allergies can trigger a range of immune-mediated symptoms, including skin irritation, colic, or poor appetite.

These reactions may be immediate (IgE-mediated) or delayed (cell-mediated). Either way, they result in inflammation that can affect your horse’s skin, gut, or overall wellbeing.

Common food allergens in horses include:

Cereal grains (oats, corn, barley, wheat)
Soy
Alfalfa
Certain vegetable proteins

Signs Your Horse Might Have a Food Allergy

Food allergies can show up in different ways—sometimes on the skin, sometimes in the digestive system, or both. If your horse has chronic, recurring issues that don’t respond to standard treatments, food could be the root cause.

Skin-Related Symptoms

Hives or bumps (urticaria)
Itchy face, neck, or body
Bald patches and skin damage from rubbing
Recurrent skin infections

Digestive Signs

Repeated mild colic episodes
Loose manure or chronic diarrhea Bloating or gas
Unexplained weight loss despite good appetite

Other Clues

Lethargy or reduced performance
Picky or fussy eating behavior

How to Diagnose Food Allergies in Horses

There’s no single test that confirms a food allergy, but a careful process of elimination can help you find the cause. Here's how to approach it:

1. Rule Out Other Conditions

Your vet will start by eliminating more common causes like:

Insect bite hypersensitivity (e.g., sweet itch)
Environmental allergies (dust, mold, pollen)
Parasites or fungal infections
Gastric ulcers or gut imbalances

2. Try an Elimination Diet (4–8 Weeks)

Remove all suspected allergens from your horse’s diet.
Switch to a novel protein (one your horse hasn’t eaten before), like pea protein, lupin, or coconut meal.
Use alternative forage like timothy or teff instead of alfalfa.
After 4–8 weeks, slowly reintroduce ingredients one by one and monitor for reactions.

3. Consider Allergy Testing

Tests like PAX Horse Allergy Xplorer measure IgE antibodies to specific proteins and can provide helpful clues to guide your elimination trial.

Managing Food Allergies in Horses: What to Feed

Once you’ve identified the offending ingredients, the key is to avoid them long-term while still meeting your horse’s nutritional needs. Here are some allergy-friendly feeding strategies:

Novel Protein & Hypoallergenic Diets

Use a single, non-reactive protein source like:

Coconut meal
Pea or lupin protein
Grain-free and soy-free feeds
Teff or timothy hay instead of alfalfa

Fiber-Based Feeding

High-fiber diets reduce allergen load while keeping your horse energized:

Beet pulp (soaked)
Haylage or soaked hay cubes
Non-legume hay varieties

Omega-3 Supplements

Omega-3 fatty acids help reduce inflammation and support skin health.