Some information on Horse Allergies

Why It Is Difficult To Diagnose Equine Allergies?

Veterinarians often tell horse owners to ask before purchasing a horse about any past allergy symptoms or outbreaks a horse has experienced. Just because a horse has had allergic reactions in the past, doesn’t mean that you shouldn’t buy the horse. If your newly purchased horse starts to come down with an allergy, you will have past health information to get the horse treated quickly and effectively.
Equine allergies can take months, or even years, to fully develop. A horse that has never been allergic to something before might develop an allergy, without warning. Undetected allergies are very difficult to prevent and diagnosis initially, since there are so many sources of environmental allergens. The horse’s age, gender, or breed is not a significant factor that contributes to allergies. Any horse can come down with hives or other skin allergies at any time in their life.

What Causes Allergies in Horses?

Many different items commonly found in any horse’s environment can cause allergies. Under normal living conditions, horses are engulfed in dust, mold spores, and other allergens all day long. In the pastures where horses graze, there are many different proteins that could potentially cause an allergic reaction. Usually a horse can fight off these allergens with a healthy immune system, but not in every circumstance.
A healthy horse’s immune system makes proteins called antibodies. Antibodies are used by the body as weapons against antigens (the allergens). When the system works correctly, the antigens are eliminated. Allergic reactions, also known as hypersensitivity, occur when the immune system overreacts to an outside antigen that is introduced to a horse’s body.
Some allergies are quite minor, while others can be life-threatening allergies that can cause problems with the cardiovascular and respiratory systems. Anything in the air, like mold or spores can cause allergic reactions. In addition, certain foods, feeds, grains, hay, nutrition supplements and insect bites can also trigger allergic reactions.

Skin Allergies in Horses

Skin allergies are among the most commonly experienced allergies in equines. They usually appear 12 to 14 hours after the horse is exposed to the antigen. Skin allergies usually appear as hives and in horses often show first around the neck and shoulders. Horses may experience fever or itchy skin when they have hives. Skin allergies can be caused by food allergens or even insect bites.
Allergic reactions caused by gnat bites are particular common in equines. Sometimes mosquito bites in certain invested areas of the United States can also be a problem. Many horses will rub the areas where the bites are present until they have very little hair or even a bald spot remaining.
Horses often recover from hives and other skin allergies without any intervention needed. However, if the hives occur often, with no apparent reason involved, a vet can do an intradermal skin test to identify the allergen. If an antigen is found through the test, hyposensitization (similar to allergy shots) may help fend off hives. In addition, corticosteroids are commonly used to treat skin allergies.

Respiratory Allergies in Horses

Heaves is the term most vets use for respiratory allergies in horses. The symptoms can include coughing, exercise intolerance and nasal discharge. It is extremely similar to asthma in humans. In some horses, owners will notice wheezing associated with respiratory allergies. There may even be a visible “heave line” in the area between the flank and the thorax. It is important to get a heaving horse treated as soon as possible because severe cases can cause weight loss.
There are several environmental issues that can cause heaves in horses. Pollen, dust, and mold, easily found in most horse stables, are the more common triggers. The best treatment to cure or relieve your horse of heaves is to identify and remove the trigger as quickly as possible.
In many cases, you can simply take the horse out of the stable and let it out to pasture for some fresh air. Also try changing the bedding to shavings or shredded paper to reduce the possible irritants in your horse’s pen area. If all standard bedding choices seem to bring on heaves, some horses must sleep on rubber mats to resolve their allergy.
Hay, common in almost all horse environments, can host many organisms that cause heaves. Soaking your hay in water can help remove any unwanted spores. If your horse still can’t stay healthy with hay in its immediate environment, owners may need to take hay out of the horse’s diet completely and replace with pelleted feed rations.
A secondary course of action that your vet can prescribe in some cases of heaves is corticosteroids. We recommend that all horse owners speak with their vet directly about any and all horse and equine medications before using them.