June 13, 2023

Trending Topic: Help, my horse has hives!

What Are Hives, Anyway?

Imagine your horse sporting itchy, raised bumps on their skin that may look like tiny mountains. Well, those pesky bumps are called hives, also known as urticaria. They can appear out of the blue and might vary in size and shape, but they all have one thing in common: they make our horses super uncomfortable.


What in the world is causing these hives?

Now, the mystery begins: The culprits can be as diverse as a horse's taste in hay.  Hives in horses occur when the horse has an allergic-type response to something called an allergen. The exact allergen that triggers hives is often difficult to determine. It's like a game of detective, trying to figure out what sparked those itchy bumps on your horse's skin. Signs of insect bites or stings can indicate the cause, as well as allergens found in food, supplements, medications (like penicillin), infectious agents such as bacteria or parasites, pollens, dust, fungi, mold spores, soaps, shampoos, detergents used for bedding, contact with leather or even exposure to certain plants. Pretty much, anything can cause them. Usually, exposure to these substances happens through inhaling or ingesting them, but sometimes direct skin contact can also lead to a reaction. Stress, light, cold, and heat have also been suggested as possible triggers. It's important to note that while some horses may react to these allergens, others in the same environment and under similar conditions may not.


Playing Detective: Finding the Trigger

To help your horse find relief, it's crucial to become a super sleuth and figure out the potential allergen. Take a moment to reflect on any changes in your horse's environment or diet before the hives appeared. Did you recently introduce a new type of feed, bedding, medications, or fly spray? Perhaps your horse had a run-in with some buzzing bugs or encountered a prickly plant in the pasture. Identifying the trigger can help you prevent future outbreaks.

Using a process of elimination to identify the cause can be quite successful. This can be done by:

·     Temporarily removing recently introduced substances or items like bedding, plants, or feeds/supplements.

·     Observing your horse closely for changes or reduction in hives over several days to weeks.

·     Once hives improve, reintroducing potential allergens one at a time, monitoring for any allergic reactions.

·     Keeping a detailed record of reintroduced substances, dates, and your horse's reactions to identify patterns.

Elimination may not always pinpoint the exact cause. If hives persist, worsen, or severe symptoms occur, consult your vet for further evaluation and possible allergy testing. There are two primary methods for allergy testing in horses: intradermal testing and blood testing.  

Intradermal testing:

This method involves injecting small amounts of various allergens into the horse's skin to observe any allergic reactions. Common allergens include various types of pollen, dust mites, molds, insects, and specific feed ingredients. A grid pattern is typically marked on the horse's side, and different allergens are injected into separate grid squares. The veterinarian will monitor the injection sites for any signs of localized swelling or inflammation, which indicate an allergic response. 

Blood testing:

Blood tests can also be used to detect specific allergens. A blood sample is taken from the horse, and the serum is analyzed for the presence of antibodies against different allergens. This method is less invasive than intradermal testing but may have limitations in terms of accuracy and specificity.


Give Them a Helping Hand:

Okay, if removing the suspected allergen did not resolve the hives, your veterinarian will discuss treatment options. These may include environmental management to reduce exposure to allergens, desensitization therapy (also known as immunotherapy or allergy shots), antihistamines, corticosteroids, or other medications to alleviate symptoms.


Final Thoughts:

Dealing with hives in our beloved horses can be a real bummer. Equine allergies can be complex and require ongoing management. Your veterinarian will guide you through the process, help you understand the results, and develop a tailored treatment plan for your horse's specific needs.