Over the counter meds for humans probably won't help him. Read more below. Kerry

Skin allergies

Symptoms: Hives, which appear 12 to 14 hours after exposure to the antigen, are the skin's show of allergies. They are areas of swelling that begin as small lumps, generally on the side of the neck, and progress across the shoulders and throat.

Initially, they may only be 1/2 - 1/2 inch in diameter but later may grow together in the target area. Hives will often indent or pit when a finger is pressed into the swelling.

Horses may appear depressed, have a slight fever, and the areas may or may not itch.

Causes: Hives can appear due to certain types of food, plants, drugs or insect bites.

Horses are susceptible to food allergies, just like humans. Likewise, it is usually impossible to identify the precise cause.

Certain grains or types of hay have been reported to cause hives in horses. The types of allergies have been associated with high protein concentrates, although this is not always the case. Horses could also be allergic to feeds that are present in other areas of the barn and not actually being fed to the allergic horse.

Horses can also be allergic to medications, either topical or internal.

The most commonly used drugs in horses implicated in allergies include non-steroidal anti-inflammatory drugs such as phenylbutazone (bute), Banamine, and procaine penicillin. Allergic reactions have also been observed after administration of tranquilizers such as acepromazine.

Hives have even been reported to occur after administration of certain vaccines such as equine influenza or tetanus antitoxin.

Insect bites can cause problems.

Hypersensitivity associated with midges or gnat bites is a common problem, although allergic reactions to mosquito bites have also been reported. The most commonly affected areas include the back, ears, mane, and tail. Itching is a characteristic feature of these types of allergies, and horses will frequently rub their manes and tails until the hair is sparse in these areas. Initially, isolated bumps may appear, with larger hives developing, too.

Treatment: Most horses affected with hives usually recover uneventfully. If hives are a recurrent problem, identification of the source can probe frustrating. Your veterinarian can perform an intradermal skin test that may be helpful identifying the problem.

If you suspect hives to be a result of a food allergy, change the grain and hay ration for at least two weeks. Then slowly reintroduce the original feed. If this stimulates the appearance of hives, you can assume that the feed is the cause of the allergy.

If the specific antigen is identified, hyposensitaization (injections to desensitize the horse to the allergen) may prove beneficial, but it is time consuming, costly and often unrewarding.

A variety of medical therapies are available through your veterinarian, with corticosteroids most commonly used. Following oral administration, remission of clinical signs is usually observed over 24 hours. Be aware that steroids may cause laminates, so don't attempt to treat the horse without first consulting your veterinarian.
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