By Alayne Blickle
While not life-threatening, insect-bite hypersensitivity can become a serious issue for horses that react to fly and midge bites.Click here to see more...
“Often horses will rub areas raw from the annoyance, and then you are left treating secondary conditions of a wound,” says Robin Knight, DVM, Dipl. ACVIM (LAIM), an internal medicine specialist at Idaho Equine Hospital, in Nampa. “You are never going to completely cure the condition because it’s an allergy, so you are left with trying to limit insect exposure and treating the symptoms–which can be frustrating.”
She says the most common clinical signs are hives and pruritus—a chronic, intense itchiness. “Horses can rub and scratch an area until it’s raw and bleeding,” Knight says.
“Sweet itch is another insect hypersensitivity with horses usually associated with Culicoides,” the little no-see-um midges that tend to come out at dawn and dusk and bite horses around the shoulders, chest, belly, neck, mane, and tail areas.
“Like any allergy there isn’t really a cure for it,” Knight explains. “We try to first to manage exposure and then the symptoms. Knowing which insects are causing the issue and keeping horses in during periods when those insects are most active can be helpful. Have a good manure management program to reduce insect breeding habitat (for flies). Culicoides are not good fliers, so putting horses in a stall with a fan (to produce a strong air current) can be helpful. Pyrethrin-based fly sprays can also be useful to keep insects off horses.”