Can horses have allergies?

As humans, many of us navigate allergies and intolerances every day – from hay fever to dietary sensitivities – but have you ever wondered whether horses can have allergies, too?

Just like us, horses are individuals with their own, unique health challenges. So, we’re going to explore some of the allergies and intolerances horses can have, and how you can help your horse if they have an allergy or intolerance.

What is the difference between an allergy and an intolerance?

For our horses, an allergic reaction happens when their immune system encounters an allergen; whether they’ve eaten something they’re allergic to, or they’ve just been in contact with it. 

The symptoms your horse could display if they have an allergy can vary from mild to severe. Here are some symptoms your horse may experience if they have an allergy:

  • Swollen mouth.
  • Urticaria (itchy or non-itchy lumps on the skin).
  • Diarrhoea.
  • Breathing difficulties.

If your horse is having breathing difficulties, please contact a vet immediately!

An intolerance usually causes milder symptoms than an allergy. The management of an intolerance can often be supported by changes to your horse’s day-to-day management and/or environment.

Signs your horse might have an intolerance:

  • Excitable behaviour.
  • Head shaking.
  • Itchy skin.
  • Hives.

Do horses get food allergies and food intolerances?

Yes, horses can get food allergies and food intolerances. However, the good news is that it’s rare for horses to have a serious food allergy!

You’ll need to contact your vet to confirm whether your horse has an allergy. The vet will ask about your horse’s medical history, and perform blood tests, to get a diagnosis. 
If your horse has an intolerance to food, you’ll need to pinpoint the exact cause to be able to improve their physical and mental wellbeing. With your vet’s guidance, you could begin an investigation into your horse’s food intolerance by eliminating certain food types and monitoring your horse’s reaction.

Known as an ‘elimination diet’, removing a food type from your horse’s feed is a process of trial and error. Your vet will help you decide which food types to eliminate and when, though here are a few of the food types known to cause intolerance in horses:

  • Barley.
  • Molasses.
  • Alfalfa.
  • Oats.
  • Specific types of hay (e.g. Timothy hay, ryegrass, etc.). 

Remember: No-matter what the cause of your horse’s food allergy or intolerance, it’s still essential that they’re getting the right nutrition for their age, breed, health, workload, etc. 

Wheat, oats, potatoes, barley and bran can provoke alergic reactions in horses

What other allergies can horses have?

Although food allergies are considered rare in horses, other types of allergies are common. Let’s explore the other types of allergies your horse might experience...

Sweet itch

The saliva of biting insects can cause an allergic reaction when your horse’s immune system attacks their own cells. 

Allergic reactions to biting insects can vary from horse to horse, ranging from very mild to extreme. If your horse has sweet itch, they might experience any of the following symptoms if they’re bitten (especially if bitten by midges or black flies!):

  • Itchiness – which could range from minor to extreme – that occurs around their face, mane, withers, and tail. 
  • Head shaking.
  • Intensely scratching against anything they can (e.g. stable doors, trees, fence posts, etc.).
  • Frequently rubbing at their mane, or back of their ears, with their hind hooves.
  • Sore, broken, flaky, inflamed skin – sometimes accompanied by hair loss.
  • Skin infections (caused by bacteria getting into damaged skin).
  • Forceful swishing of their tail whenever there’s insects around.
  • Restlessness or agitated behaviour.

While there’s currently no cure for sweet itch, there are several ways you can manage it to improve your horse’s quality of life:

  • Covering as much of your horse’s body as possible, using fly rugs and fly masks designed specifically for those with sweet itch.
  • Use fly repellent products that are vet-approved and known to be effective at deterring biting flies.
  • Keeping your horse stabled when flies are about (e.g. stabling your horse from dawn to dusk during the summer).
  • Set up a fan that faces your horse’s stable, to keep flies away from them.
  • Muck-out their stable and poo-pick their field twice a day.
  • Position the muck-heap away from your horse’s stable and field.
  • Clean water troughs every day, to stop flies from hovering around them.
  • Avoid turning your horse out when the field is muddy and/or waterlogged.
  • Make sure your horse stays away from stagnant (still) water sources, like ponds.

Always speak to a vet about managing your horse’s sweet itch, since there are special lotions, shampoos, and even medications that can be used to ease your horse’s discomfort.

Dust allergy

In horses, dust allergies are experienced when airborne allergens or dust mites cause their immune system to overreact. 

Symptoms of a dust allergy in horses include:

  • Watery, itchy eyes.
  • Runny nose.
  • Itchy legs.
  • Coughing.
  • Breathing problems (e.g. equine asthma or ‘COPD’).

To limit the impact of a dust allergy, you can make changes to your horse’s environment by:

  • Turning them out as much as possible (to limit time spent in their stable).
  • Using dust-free bedding.
  • Dampening their dry feed with water.
  • Choosing high-quality hay or haylage.
  • Steaming their hay.
  • Adding a vet-approved breathing supplement to their feed.

A vet and/or equine nutritionist should be able to provide specific advice on managing a dust allergy, based on your horse’s individual situation. 

Horse allergies caused by diet can be identified and managed fairly easily

Pollen allergy

Despite their field-focused lifestyle, horses can develop a pollen allergy!

Just like a dust allergy, a pollen allergy is triggered by airborne particles and can result in your horse:

  • Head shaking.
  • Having runny eyes.
  • Coughing.
  • Experiencing decreased energy levels.
  • Lacking concentration.

Thankfully, there are ways to help your horse feel more comfortable during spring and summer, when pollen allergies are at their worst:

  • Find out which type of pollen affects your horse (ask a vet to help!).
  • Keep your horse stabled during the day.
  • Where possible, avoid exercising your horse when pollen counts are high.
  • Put a nose net onto their bridle, to limit head shaking.
  • During turnout, put a fly mask on them (though it needs to provide ear, eye, and nose protection).
  • Add a vet-approved respiratory supplement to their feed.

Ultimately, while allergies and intolerances are incurable, there are plenty of remedies and management strategies available to help your horse feel better. 

It’s important not to diagnose your horse’s allergy or intolerance yourself, though. Please speak to a vet if you feel that changes to your horse’s health and/or behaviour could be caused by an allergy or intolerance.

Don’t forget to check out our glossary if you’ve encountered an unfamiliar equestrian term!

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