Imagine you treat your horse’s fungus with a common product, go home and feel good that he’s on the mend. Then imagine waking up to your horse being covered in an explosion of red angry sores, all caused by the product that was supposed to help.
“He was completely covered in open sores that were bleeding and crusty,” says amateur eventer Sarah Edwards, speaking of an incident a few years ago involving her Appendix Quarter Horse. “I called the vet out, and it turned out to be an allergic reaction to M-T-G. There was hardly any hair left where I had sprayed. It took weeks to clear up.”
While this case sounds extreme, horses can suffer from skin allergies caused by a number of common triggers, from bugs and airborne allergens to plants, topical medications and grooming products. Telltale signs of allergies affecting a horse’s skin include itchy hives, hair loss, scaling, hyperpigmentation, self-trauma or excessive scratching or rubbing. Sometimes, even head tossing and laminitis can be signs of allergies, according to Dr. Laura Petroski, a veterinarian with Kentucky Equine Research.
Look For the Source
If your horse is showing any of these signs, it might be time to look for allergic triggers. This time of year, hypersensitivity to insect bites is one of the most common causes, which is often called allergic dermatitis or sweet itch. “When insects are out, that’s when we see more allergic-type of skin reactions,” says Dr. Fernanda Camargo, an associate professor and equine extension specialist at the University of Kentucky.
Sometimes they can become severe and cause anaphylactic shock, which can suffocate the horse.
But she notes that process of elimination is the best way to find the cause. “Some horses are known to be allergic to fly bites, so if he comes from the outside full of hives and it’s insect season, that’s probably what it is.” If bug bites aren’t the issue, look for other causes such as contact with paint, fly spray or topical medications. Did you use a new shampoo? New ointment? If the horse has hives and he was blanketed, the culprit could be the fabric softener or detergent you washed the blanket with. “If it’s something that is only affecting his legs — maybe it’s the weeds in his pasture,” Dr. Camargo said.
Be vigilant when applying anything to your horse, especially if it’s a new product. “If you use a topical medication, or fly spray, and within a few minutes, the horse starts to kick repeatedly, you need to wash the product off immediately before it causes a more severe reaction,” she says. “It’s bad horsemanship to just spray or apply something and not pay attention to the horse for at least a few minutes before leaving him.”
Skin Allergy Management and Treatment
For skin allergy management, removing exposure is step one. To prevent insect bite allergies, use fly sheets, masks and fly spray and bring the horse inside during peak times for insects (usually sunrise and sunset). Manage barn fly populations by removing manure as soon as possible and providing fans in walkways and on stall doors.
If your horse has developed hives, it’s time for the vet. “You need to call the vet so he can medicate the horse before it becomes severe,” explains Dr. Camargo. “Generally, skin urticaria will disappear as soon as the offending substance is removed, may it be a topical product or mosquito bites. But sometimes they can become severe and cause anaphylactic shock, which can suffocate the horse.”
It’s bad horsemanship to just spray or apply something and not pay attention to the horse for at least a few minutes before leaving him.
For hives, your vet will likely administer an anti-inflammatory steroid, after which the hives can start to go away within minutes. Sometimes, though, hives can trigger an anaphylactic attack, or anaphylaxis can develop on its own. If this happens, act quickly to seek medical attention — very quickly. “When horses can’t breathe, if they are wheezing, are struggling to breathe, have swollen nostrils, mouth, eyes, etc., they may be having an anaphylactic attack. This is always an emergency,” explains Dr. Camargo.
Proper Maintenance and Ongoing Treatment
After seeking vet treatment, medical management of skin allergies might not be over. Sometimes horses can develop scaly bumps or secondary infections and irritations from scratching, and that sensitive and uncomfortable skin needs soothing. Try creams and sprays meant for contact dermatitis, and topical steroids such as hydrocortisone. Products with oatmeal or lime sulfur can help as well.
“Shampooing and bathing your horse in cool water may be very therapeutic for some horses, especially those with secondary skin infections,” describes Dr. Petroski. “There are many, many different types of shampoos that contain ingredients geared toward addressing some of those secondary issues brought on by the allergies.”
But, she warns to ask your vet before using any product in an effort to not bring on another reaction.