What Are the Treatments for Hives in Horses?

Treatment for equine hives includes a combination of oral and topical medications for the skin swellings to reduce in size and disappear, as well as itching. Triggers cause a mast cell to release its contents to blood vessels in the skin and leak fluid to the middle skin layer creating a lump, or wheal, that is raised and red. Your veterinarian will conduct a skin and/or blood test to determine the trigger and prescribe a course of treatment.

Symptoms of Equine Hives

Horses can get hives, or urticaria, at any time of the year, though it is more prevalent in the summer months. Equine hives are circular wheals that cover a large portion of a horse's body. The round areas may be itchy, though that it is not always the case. When you touch the rounded, raised areas, they are not hot to the touch. The hair on top of the hives will often stand up and may fall out. Each wheal lasts from 24 to 48 hours and occurs most often on the neck, legs and trunk.

Causes of Equine Hives

Nonimmunologic causes of equine hives include skin pressure, heat, cold, stress, exercise, sunlight and genetics. Immunologic causes include bite sensitivity from insects such as stable flies, biting midges, horse flies, mosquitoes and chiggers. Other causes of equine hives include drug reactions to dewormers, vaccines, antibiotics, medications, vitamins and supplements, or skin dermatitis caused by fly spray or bedding.

Equine Hives Diagnosis

Your veterinarian likely will use intradermal skin testing to determine which allergen is causing hives on a horse. Veterinarians also may take a blood sample to test it for allergens in recurring cases of hives.

Equine Hives Treatment

Treatment of hives may include one or more of the following:

  • Topical antipruritics to relieve itching.
  • Topical steroids.
  • Oral steroids.
  • Antihistamines.
  • Immunomodulatory oral drugs to treat autoimmune conditions.

Chronic hives in horses often are treated with prednisone for continuous control.

Management of Equine Hives

Several changes in your horses outside activities can help manage hives. Keeping horses in a stall at dusk and dawn when biting insects are at their peak with a fan in the area discourages insects. Screening in open stalls in barns keeps insects from entering your horse stalls. Flysheets and masks prevent bugs from biting your horse. You can apply fly repellent on your horse twice a day to repel flying insects. Treatment of hives as directed by your vet and the above management techniques can keep your horse comfortable without hives.