Food Allergies in Horses: Diagnosis, Management & Nutrition Strategies

Allergies in horses can be challenging to identify, as they often mimic other conditions and worsen with seasonal exposure.

While environmental triggers are the most common cause, some horses may show signs that raise concern about food allergies. True food allergies, however, are rare, and misdiagnosis can lead to unnecessary dietary changes.

This article explains the differences between environmental allergies, food allergies, and intolerances, outlines key symptoms, and highlights nutritional strategies to help horses stay healthy, comfortable, and performing at their best.

Horse Allergies: Different Types, Symptoms, and How Often They Occur

Allergies in horses can appear in many forms, ranging from skin irritation to respiratory issues and, in rare cases, food-related reactions. Understanding the different types of allergies, their symptoms, and the frequency at which they occur helps owners and veterinarians identify the cause and choose the most effective management approach.

Environmental Allergies

Environmental triggers often intensify in spring and summer. Research suggests that some horses may be genetically predisposed to allergic responses, most often to inhaled triggers such as pollen or dust mites. 
Horses are regularly exposed to common allergens such as:

  • Insects
  • Mold
  • Pollen
  • Dust
  • Topical products
  • Tack and equipment

Equine atopic dermatitis is a common allergic skin condition linked to environmental triggers, and is characterized by:

  • Skin inflammation
  • Intense itching
  • Hair loss
  • Lesions/scabs

Horses affected by environmental allergens may also exhibit respiratory signs, such as:

  • Nasal discharge
  • Coughing
  • Difficulty breathing

Diagnosis requires a physical examination and a thorough review of the horse's medical history. Management of these types of allergies focuses on reducing exposure through dietary and environmental adjustments. In severe cases, antihistamines or corticosteroids may be prescribed to control inflammation and itching. 

Food Allergies

A food allergy develops when a horse’s immune system mistakes specific feed proteins as harmful. In response, it produces Immunoglobulin E (IgE) antibodies that, upon re-exposure to the same proteins, trigger the release of histamine and other inflammatory chemicals.

This can trigger symptoms such as:

  • Itching
  • Hives
  • Digestive upset

Commonly suspected dietary triggers include:

  • Alfalfa
  • Soy
  • Oats
  • Wheat

These cases are often confused with food intolerances, which are different than a true allergy. Because feed is easier to control than environmental triggers, horse owners frequently focus on food allergies first.

However, caution should be exercised before making significant dietary changes without consulting an equine nutritionist or veterinarian. For example, if a horse has thrived on a feed for a long time, it’s unlikely to be the cause of new allergy symptoms. Veterinarians typically rule out environmental allergens as the first step in the diagnosis.

Allergies vs. Intolerances

Food allergies and food intolerances are often confused, but they are fundamentally different.

Allergies involve the immune system, where a horse's body mistakenly reacts to specific proteins that trigger an inflammatory response. Intolerances, on the other hand, do not involve the immune system.

Instead, they stem from non-immune mechanisms such as enzyme deficiencies or sensitivities to specific food components. For example, in humans, lactose intolerance develops when the body lacks the enzyme necessary to digest lactose, resulting in bloating, gas, and diarrhea after consuming dairy products.

Timing can also help distinguish the two conditions. Allergic reactions often appear quickly, within minutes to hours of exposure, while intolerance symptoms may take longer to develop, sometimes surfacing hours or even days after the feed is consumed.
In horses, food intolerances are less well-documented than true food allergies but can still occur. Food intolerance symptoms may include:

  • Gastrointestinal issues such as colic, diarrhea, or changes in manure consistency
  • Mild skin irritation
  • A dull coat
  • Behavioral changes related to digestive discomfort

How Are Equine Food Allergies Diagnosed: When and Why to Test

Equine allergy testing can play a role in diagnosis in certain situations. Horses may be tested when unexplained allergy-related symptoms arise.

Testing may also be considered when food-related allergies are suspected after environmental causes have been ruled out, or before starting immunotherapy to identify which environmental allergens to target. Identifying triggering ingredients can help horse owners, veterinarians, and equine nutritionists design a safer, more effective diet plan to manage the horse’s unique condition.

Blood Testing

Blood testing measures the level of immunoglobulin E (IgE) antibodies, which rise when the immune system overreacts to an allergen. While blood tests are convenient to run in the field, they are notoriously unreliable and often produce false positives.

A 2016 study tested the reliability of a commercial blood allergy panel in ponies. Researchers evaluated 17 ponies at two different time points. Seven ponies tested negative both times, three tested positive both times, and only one tested positive for the same allergen on both occasions.

When the ponies were later exposed to the allergens flagged by the test, none showed clinical signs of an allergy, such as hives, itching, changes in heart rate, or elevated temperature.

Intradermal Testing

Intradermal testing is generally considered more accurate than blood testing. However, it is also more intensive, costly, and not a valid method for diagnosing food allergies in horses.

Veterinary dermatologists emphasize that, like blood tests, intradermal testing cannot reliably detect food-related allergies. Instead, it serves as the gold standard for identifying environmental allergies.

Even then, the test is not foolproof—false positives and negatives are possible, and a positive skin reaction does not always translate into a true allergic response in a horse’s everyday environment.

The procedure itself is also intensive, requiring sedation, shaving a significant patch of the horse’s coat, and withdrawal of certain medications before testing. 

How to Use an Elimination Diet to Identify Food Allergies in Horses

An elimination diet is the most reliable method for diagnosing food allergies in horses. The process begins with a hay-only diet for several weeks, allowing symptoms to stabilize or resolve.

Once a baseline is established, individual feed ingredients are gradually reintroduced, one at a time, while closely monitoring for the return of symptoms such as skin irritation, digestive upset, respiratory issues, or behavioral changes.

This two-phase process—elimination followed by reintroduction—helps identify specific allergens by confirming which ingredients trigger a reaction. Because the trial is restrictive and requires careful observation, it should always be conducted under the guidance of a veterinarian and an equine nutritionist.

Their expertise ensures the horse continues to receive balanced nutrition and that any allergic reactions during reintroduction are managed safely. While elimination diets can be time-consuming and demand patience, they remain the gold standard for accurately diagnosing true food allergies in horses.

Nutritional Management & Feed Strategies for Equine Food Allergies

When food allergies are suspected, nutrition plays a central role in managing symptoms and supporting overall health. Because true food allergies in horses are rare, the goal is not to completely change the horse's entire diet all at once, but rather to identify and avoid specific triggers while maintaining a balanced diet.

Avoiding Common Allergenic Ingredients & Hypoallergenic Diets

If a horse reacts to a specific ingredient, selecting feeds and supplements that exclude it—and working with a veterinarian or nutritionist—ensures the ingredient is properly eliminated from the diet.  Some ingredients are more frequently suspected of causing allergic reactions in horses, commonly including:

  • Alfalfa
  • Soy
  • Oats
  • Wheat

For horses with confirmed or strongly suspected food allergies, a simpler diet is often better. A hypoallergenic diet typically relies on a consistent forage base, paired with a limited number of grain, concentrates or supplements. The fewer ingredients in the feed, the easier it becomes to track and control potential triggers.

Omega-3 Fatty Acids

Omega-3 fatty acids, particularly those from hemp, flax, canola oils, or marine sources, provide natural anti-inflammatory support.

They may help reduce skin irritation and promote coat health in horses with allergies or sensitive skin. Adding an omega-3 supplement to the diet can support a healthier inflammatory response and ease discomfort.

Other Supplement Considerations

In addition to providing anti-inflammatory support, digestive health supplements may also play a role in managing allergies in horses. Probiotics and prebiotics can help stabilize the gut microbiome, which supports nutrient absorption and immune balance.

For overall skin health, supplements rich in fatty acids, antioxidants, or specific vitamins may help strengthen the skin barrier and reduce irritation.

Working With an Equine Nutritionist

Because food allergies are rare and can be easily misdiagnosed, consulting with an equine nutritionist ensures that dietary changes are effective and nutritionally balanced.

A nutritionist can help formulate a complete feeding plan that avoids suspected allergens while still meeting the horse’s energy, protein, vitamin, and mineral requirements. This professional guidance also reduces the risk of creating nutritional gaps when certain ingredients are removed.

How Tribute Nutrition’s Feeds, Supplements, and Customized Plans Help Manage Equine Allergies

Managing both food and other types of allergies and intolerances in horses requires a careful balance between avoiding triggers and ensuring all nutritional needs are met. Tribute Nutrition offers a wide range of feeds with clearly defined ingredient lists, making it easier to avoid common allergen suspects, such as alfalfa, soy, oats, and wheat, when necessary. 

Tribute also provides targeted support through products like Wholesome Blends™ Omega Plus, which offers natural anti-inflammatory support through its omega–3–rich blend of hemp, canola, and flax oils. This blend helps improve coat quality, maintain body condition, strengthen immune health, and aid in exercise recovery.

Natural Remedy™ is a DHA supplement also designed to support horses facing allergies by promoting immune balance, respiratory function, and reducing irritation and inflammation.

Tribute’s Constant Comfort® Plus is another great option for horses with allergies. Its blend of probiotics, prebiotics, and buffering agents supports gut health, strengthens immune balance, and helps reduce digestive stress that can worsen allergy symptoms.

The Tribute Nutrition team offers free, customized feeding plans to help horse owners navigate the process of removing problematic ingredients, selecting ideal feed and supplements, while still delivering complete and balanced nutrition.

In developing personalized feed plans, Tribute’s team considers the horse’s environment, overall health, and performance needs. These tailored programs support allergy management while also promoting long-term equine well-being and optimal performance.

References

Article By:
Nicole Rambo, Ph.D.
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