Allergic Hair Loss in Horses

The condition of a horse's hair is an accurate guide to its overall health. Horses rely on their hair for protection from the elements and regulation of temperature. Allergic hair loss in horses can leave skin open to infections from bacteria and fungi or invasions by insects such as mites. Preventative measures include keeping both horse and stall scrupulously clean and providing a balanced, nutritious diet.

  1. Food Allergies

    • Food allergies that cause horses to lose hair are not common, but may go unidentified, because they closely resemble other conditions, such as colic. Causes include an allergy to part of a horse's feed, most frequently the wheat or corn, and digestive problems causing inflammation of the intestines. Symptoms of food allergies include loss of weight and appetite, diarrhea, weakness and lack of energy. If your horse also has dull hair, refuses his favorite foods and becomes irritated easily, see a veterinarian to get your horse tested for the food that is causing this hair loss.

    Fly Allergies

    • Horses that become allergic to the bites of flying insects lose their hair and are at risk of infections entering the patches of unprotected skin. Allergic reactions to insects manifest as symptoms such as lesions, skin redness, hives, ulcers and pustules, as well as hair loss. Several types of flies are responsible for this condition. The small culicoides fly attacks the tail and mane, horseflies or deer flies bite the chest and flanks and horn fly bites are usually on the ventral midline. Remember, it only takes a few bites to produce an allergic reaction. Solutions include vet-approved fly-control sprays and stabling early and late in the day. Open areas of skin must be dressed to prevent infections.

    Chemical Allergies

    • Just like humans, horses can be allergic to many of the chemicals they come into contact with. This is one of the simplest allergies to treat, once the irritating chemical is discovered and removed. Possible causes of chemical allergies include grooming aids such as shampoo, fly sprays and detergents used to launder horse bedding. More difficult chemical sources of allergies that lead to hair loss in horses involve reactions to prescribed medicines. Consult your vet when your horse experiences hair loss immediately after starting a new medication.

    Parasitic Allergies

    • External parasites like horse lice and fleas, as well as internal parasites such as worms, cause hair loss in horses. External parasites aggravate horses, causing them to rub any part of their skin against objects to relieve the severe itching. Worm-related hair loss is particularly noticeable in the tail. Ask your vet to test the blood of a horse suspected to suffer from parasitic allergies. Keep the horse and his surroundings clean and bear in mind that parasites can be transferred to other horses.