“Sweet…”, as a modern term, denotes pleasure and enjoyment. However, for a horse, sweet itch can be anything but “sweet…”.
“Sweet Itch, also known as summer eczema or equine dermatitis, is one of several seasonal allergies that your horse may encounter,” notes Dr. Glennon Mays, clinical associate professor at the Texas A&M College of Veterinary Medicine & Biomedical Sciences.
“Equine dermatitis can have varying causes,” explains Mays. “Allergens may irritant your horse’s skin, but viruses and bacteria may also manifest themselves as dermatitis. These foreign agents can cause inflammatory conditions in the skin and may affect your horse’s hair coat. Equine sweet itch is a seasonal allergic skin condition that can be caused by fly bites or midge bites. Horses that suffer from sweet itch have developed an allergy to these bites.”
Insects flourish in the summer and horses may have sensitivities to insect bites, notes Mays. In particular, black flies, known as buffalo gnats, can seek horses as hosts. These flies feed on the blood of mammals and are attracted to hosts by smell, heat and sight. They prefer the host’s head, hair and ears but will also bite any skin that is exposed.
“The female black flies are blood feeders,” explains Mays.
Black flies feed during the day. Fly repellents applied to the chest, belly and ears can be effective if applied daily, says Mays. Cloth coverings fitted over horses’ ears may be used for additional protection.
“Allergic dermatitis can result from the black fly bite,” states Mays. “Antigens in their saliva can cause allergic reactions. Additionally, the black fly bite can become painful and itchy as blisters form. Therefore, protecting the face and ears from flies eliminates a major source of irritation for your horse.”
Equine dermatitis will usually result in symptoms such as scratching, biting affected area, crusts, hair coat damage or loss, flaky dandruff and thickened skin, explains Mays. The itchy skin can be further irritated when the horse rubs the area (on fences or stalls) to the point of hair loss and scabbed skin.