Photo: Courtesy Dr. Marianne Sloet
Although summer is winding down in some parts of the country, insect-sensitive horses might still be battling bugs. For the particularly reactive horse, a "sweet itch blanket" can provide some relief.
The Horse.com spoke with world-renowned sweet itch specialist and researcher, professor Marianne Sloet van Oldruitenborgh-Oosterbaan, DVM, PhD, Dipl. ECEIM, Specialist KNMvD Equine Internal Medicine, from the Department of Equine Sciences at Utrecht University in The Netherlands, to make sure you’re “covered” from head to toe on what you need to know about sweet itch blankets.
TheHorse.com: What is sweet itch?
Marianne Sloet: Sweet itch—also known as summer eczema, seasonal equine dermatitis, or more accurately, insect-bite hypersensitivity—is an allergic skin reaction to the saliva of the Culicoides biting midge. Horses with this condition suffer from severe itch throughout the active midge season—usually from about April to September.
Affected horses scratch excessively, causing hair loss (especially in the mane and tail) and even abrasions. Sometimes the irritation is also on the belly.
There is no effective treatment for sweet itch and no cure (although our research teams are hard at work on both these goals). The best management tool is prevention—essentially keeping the midges off the horse. And the best way to do that is to move to an area without midges (not an easy solution), or to use an effective fly repellant and especially a good sweet itch blanket designed for the disease.
TH.com: So what should we look for in a good sweet itch blanket?
MS: A sweet itch blanket is different from regular fly blankets because it has to do more than just reduce the number of insect bites. It needs to stop midges from getting to the horse’s skin altogether. So look for a well-fitted blanket with neck cover and even a hood to cover the head if the horse is especially sensitive.
Stretchy blankets will fit better and move more with the horse, but you have to balance stretch with durability. Ideally you’ll find a fabric that is both stretchable and durable. Elastic fittings around the limbs are nice but not necessary so long as there’s a form-fitting belly part.
Some come impregnated with insect repellant, which can be an added bonus. But you can also spray the blanket (and the uncovered parts of the horse) with insect repellant yourself. Also, make sure the blanket is breathable since the horse will be wearing it almost nonstop during the summer.
TH.com: When should we start blanketing?
MS: Definitely before the itchy season starts, so as soon as the temperatures start to rise about 10-15 degrees Celsius (50-60 degrees Fahrenheit). If you wait until after the horse is already itchy to blanket him, he will destroy your beautiful new blanket by scratching himself against anything he can.
If you didn’t start blanketing before the itch, though, that doesn’t mean you shouldn’t blanket. Just ask your vet for a steroid treatment (such as oral prednisolone in the early morning) for about the first two weeks. (Be careful if you have a competition horse, though, because this medication will show up positive on a drug test; incidentally, it might also provoke laminitis.)
TH.com: If the midges only come out at dawn and dusk, couldn’t we just blanket them during these times?
MS: You could, but our research shows that midges will still come out and bite horses, although at a lesser scale, outside of their peak hours of sunrise and sunset. It’s true that most of them are out at dawn. But a hypersensitive horse—one that has developed the allergy—can react with very little exposure to the allergen. All it takes is one midge bite for the sweet itch to flare up again. So usually it’s easier and more prudent just to keep horses covered.
TH.com: Do horses have to wear their blankets while we’re riding them?
MS: No, that’s not necessary. Our experience has shown that midges aren’t really interested in horses that are in motion. But do use insect repellant during your ride for the slow periods or the cooling down at the end of the ride.
TH.com: Don’t the horses get too hot in the summer heat with those blankets on?
MS: A well-designed blanket is not going to cause a heat problem. Light-colored blankets like white or gray are going to show dirt more easily, but if you’re in a hot climate then these are the colors that will absorb the least heat and will be more comfortable for your horse.
Also, as I mentioned earlier, make sure your blanket is made of breathable fabric so the horse’s skin benefits from a healthy gas exchange, which will keep him cool in the heat. That being said, a sweet itch horse—just like any other horse—needs access to plenty of shade and water during the hot summer months.
TH.com: What about other insects? Should our sweet itch blanket prevent bites from mosquitoes and horse flies, too?
MS: Mosquito bites and horse fly bites are indeed annoying and painful, and they can itch. But in most cases they won’t cause sweet itch. So you can try to keep all flying pests off your sweet itch horse if you want, but your main goal will be to ward off those Culicoides midges.
TH.com: And finally, how long should the sweet itch blankets last?
MS: Several years! So it’s worthwhile to invest in a good one. Our research group has been pleased with custom-made blankets by a Dutch company specializing in eczema blankets (Ivanhoe Horse Equipment). But any company making blankets with the specifications I mentioned earlier should be able to provide you and your horse with equivalent quality and protection against sweet itch.
About the Author
Christa Lesté-Lasserre is a freelance writer based in France. A native of Dallas, Texas, Lesté-Lasserre grew up riding Quarter Horses, Appaloosas, and Shetland Ponies. She holds a master’s degree in English, specializing in creative writing, from the University of Mississippi in Oxford and earned a bachelor's in journalism and creative writing with a minor in sciences from Baylor University in Waco, Texas. She currently keeps her two Trakehners at home near Paris. Follow Lesté-Lasserre on Twitter @christalestelas.