Learn how to manage equine allergies effectively with tips on treatment, prevention, and seasonal care, so your horse can thrive during spring and summer.
All horse owners have experienced it: the cough on a warm spring day, the yellow mucus caked in a nostril. While the arrival of spring and summer typically brings fairer riding conditions, it also brings allergies. Pastures of clover, hordes of flies, and thousands of types of pollen ambush horses at every turn during the warmer seasons. It’s no wonder that about 10% to 14% of horses suffer from allergy-related health issues.
Although allergies can affect horses in any season, they are most common in spring and summer when the hot weather brings countless potential allergens to life. So, what are the main culprits behind equine allergies during the growing season, and what can horse owners do to combat them?
Causes of Spring and Summer Allergies
Allergies in horses can result from genetic factors or from the numerous allergens they encounter daily. Allergens—substances that trigger allergic reactions—are found in almost everything, from hay and dust to vaccinations and topical medicines. While these allergens are present year-round, what causes the increase in allergic reactions during spring and summer?
In spring, reviving plants and returning insects are often to blame for horses’ runny noses and dull coughs. Pollen is the biggest contributor to spring allergies, but bug bites are also common triggers. Many trees, such as oak, elm, maple, and mulberry, produce allergens, as do grasses like Bermuda, fescue, perennial, and rye. Weeds such as ragweed and sagebrush are also known allergen producers. Insects responsible for springtime allergies include gnats, mosquitoes, horse flies, black flies, stable flies, and biting midges, commonly known as “no-see-ums.”
These allergens are largely the same culprits behind summer allergies as well.
Allergy Symptoms
Allergy symptoms in horses are relatively easy to identify. Itching and hives commonly accompany skin allergies, while coughing, watery eyes, and nasal discharge are typical of respiratory allergies. However, allergy symptoms can vary widely, and not every horse will display the most obvious signs. Some horses may wheeze instead of cough, shake their heads, or develop swelling near the site of irritation for skin allergies. Hair loss from scratching and dry skin can also indicate allergies.
Like humans, horses can experience anaphylaxis due to allergies. Anaphylaxis is a severe, life-threatening allergic reaction that can occur within seconds or minutes of exposure. It is characterized by a dramatic drop in blood pressure, labored breathing, aggressive hives, a weak pulse, and even collapse. Anaphylaxis is a medical emergency and requires immediate veterinary care. Veterinarians can administer medications such as epinephrine and dexamethasone to treat the reaction.
Allergy Treatments
There are many options for treating equine allergies. Antihistamines are common, and oral ones such as diphenhydramine, cetirizine, and hydroxyzine are frequently used.
Diphenhydramine, or Benadryl, must be obtained through a veterinarian and is typically only used in emergencies since it is not FDA-approved for equines. Giving it for extended periods is not advised. Cetirizine, known as Zyrtec in human medicine, is available without a prescription, although its effectiveness in horses is questionable. A veterinarian’s prescription is necessary for hydroxyzine (Atarax or Vistaril), which is usually given as needed and is not meant for indefinite use.
Common corticosteroids used to treat allergies include dexamethasone, prednisolone, and triamcinolone acetonide, all of which require a veterinarian’s prescription. Steroids offer more immediate relief from allergic reactions and are typically administered as needed, although they are sometimes given long-term.
Another option is allergen-specific immunotherapy, or ASIT. This treatment involves allergy testing the horse so individualized injections of allergens can be created to gradually desensitize its immune system. ASIT provides a more permanent solution to allergies, as it can potentially eliminate symptoms entirely, allowing a horse to discontinue allergy medications.
Additionally, there are numerous supplements available online marketed as allergy treatments. Horse owners can experiment with different products to determine what works best for their horse.
It is also worth noting that some allergy solutions may be simple fixes. If a horse’s allergens are known, limiting contact with irritating substances like hay and dust can reduce symptoms. If flies are the cause, more frequent stall cleaning and regular application of fly spray can help reduce pests in the barn.
Allergies are annoying for both horse and owner, but they are manageable. Finding the right treatment for each horse may take time, but relief is achievable. Hopefully, as we move into spring and summer armed with this knowledge, we can combat the coughing, sneezing and itching so our horses can enjoy the warmer months and perform their best.
To read more horse health articles click here . To view American Association of Equine Practitioners (AAEP) horse owner horse health articles click here . To visit Equine Disease Communication Center for horse health alerts click here .
