BY TORI BILAS/JUMP MEDIA
Got allergies? Well, chances are, your horses do, too.
With warmer temperatures and spring blooms pushing up pollen levels, it seems like everyone at the barn – human and animal – is coughing and congested. If you have ever wondered what you can do to help a horse suffering from allergies, Palm Beach Equine Clinic veterinarian Dr. David Priest shares his knowledge on addressing allergies and helping horses breathe easy. In his daily veterinary work, Dr. Priest primarily focuses on equine respiratory health. He is experienced in treating conditions ranging from concerning coughs to obstructive or mechanical issues affecting airway function, such as recurrent laryngeal neuropathy (commonly known as “roaring”).
Types and Triggers of Equine Allergies
An allergy is an immune system response to a typically harmless substance, called an allergen. Allergic reactions can range from mild, gradual annoyances to sudden and severe. Generally, allergies manifest two ways in horses: in the respiratory tract or as topical skin allergies.
Respiratory allergies are somewhat similar to asthma in humans and are most commonly referred to as inflammatory airway disease. These respiratory allergies are most often caused by environmental allergens, such as dust, mold, and pollen. Nasal discharge, tearing eyes, and coughing can also be linked to respiratory allergies.
An increase in respiratory rate or an increase in respiratory effort, such as labored breathing or exercise intolerance, are two classic signs. Also, when a horse has a thick mucus-like discharge from its nasal passages, it is concerning to veterinarians as it could indicate an infectious type of respiratory illness. A veterinarian can distinguish whether the culprit is an allergen or if there is an underlying mechanical cause of the respiratory issue. Additionally, horses that experience a dramatic change in environment may be affected. For example, those traveling from New York to Florida may suffer from completely different allergens such as tree pollens or smoke caused by the burning of sugarcane fields.
Allergies affecting the skin commonly appear as hives, dermatitis, or hair loss. The administration of topical products as well as a change in the type of stall bedding can trigger such reactions. Topical skin reactions can occur in a specific area or cover the horse’s entire body. Allergies to the common bacteria Dermatophilosis can occur resulting in a painful skin condition. Oftentimes, antifungal or bacterial shampoos can help alleviate this reaction. Consulting your veterinarian is key to determining if your horse suffers from allergies that may undermine your horse’s health or future.
The same allergens that cause respiratory symptoms can also cause skin reactions, but veterinarians tend to approach treatments differently for the two types of reactions.
Diagnosing Equine Allergies
Like most conditions, your veterinarian will start by getting a history of the problem, including when it first appeared, and any changes that may have occurred recently in the horse’s diet or environment. They will follow with a physical examination, noting the site or region of the horse’s body where there is a flare up. Specific tests such as a biopsy and culture can be performed to rule out other skin conditions or causes such as parasites, bacteria, or tumors. A bronchoalveolar lavage (BAL), or a tracheal wash where the veterinarian collects respiratory secretions and then performs a cytology of that fluid, can determine if there are abnormalities or specific types of bacteria causing an infection. Serum (blood) allergy testing or imaging, such as an ultrasound of their chest, may be utilized to assess airway health and function and determine if the cause is allergy related.
As in a visit to the human allergist, horses can undergo intradermal (skin) allergy testing to pinpoint the source of a horse’s reaction. For this procedure, the horse has a large patch of hair clipped down on their neck so that tiny amounts of various allergens can be injected into a grid pattern. The veterinarian will examine this grid during different time intervals for signs of an allergic response and determine if a targeted treatment can be taken against those specific allergens.
Treatment and Taking Action Against Allergens
Once the veterinarian determines that your horse is suffering from allergies and not another condition, the first thing you can do is try to identify and eliminate the allergen. Figuring out what may have been associated with the onset of the allergic reaction is an inexpensive solution, and often the most effective approach.
From a stable-wide perspective, the most important thing you can do is try to minimize dust and flies, two of the most common allergens. While horses are not generally allergic to flies, some can be allergic to fly bites or specific fly species. Insect bites also increase the horse’s stress level, which can further contribute to the immune system’s response. While eliminating insects and environmental allergens is impossible, there are several tactics barn managers can take to mitigate both problems.
A good manure disposal system can cut the population of insects in the barn, as will a reduction in any standing water, especially in the springtime when flies and mosquitoes start to reemerge. Owners can protect their horse from insects by using fly sprays, masks, sheets, and boots, and by keeping horses inside during times of the days when bugs are most active. Dust- and pollen-related allergic reactions tend to occur when horses are in the barn because it is a closed-air environment. Dust control tactics, such as wetting hay and shavings, keeping barn aisles clean and swept, and managing fresh airflow in the barn with fans and open doors and windows all contribute to better airflow.
Veterinary treatment is the next line of defense in treating allergies. For acute reactions, some horses benefit from short-term treatment with corticosteroids or antihistamines. Those treatments, however, can have side effects and are prescribed when other interventions, such as modifying the environment to reduce the allergen, are ineffective. Immunomodulatory therapy (allergy shots) is another option that may be effective and can be discussed with your veterinarian.
Knowing how to identify allergies affecting your horse and taking steps to eliminate the allergens will lead to easier breathing and happier horses in your stable. For more information, contact Dr. David Priest at Palm Beach Equine Clinic by calling 561-793-1599 or visit EquineClinic.com.