Equine allergies are always frustrating.
A chronic cough, raised lumps on the shoulder, tearing eyes, whatever, it is often difficult to diagnose the cause of an allergy.
One reason is that an allergy may take months or years of exposure to develop, so it is often the source of the problems. To further complicate matters, there does not appear to be any link between age, gender or breed and the development of hives or skin allergies.
(When buying a horse, ask questions about any previous allergic reactions it may have experienced so you can be prepared.)
Understanding the symptoms, causes and treatments can help identify whether your horse odes, indeed, have an allergy.
Horses are surrounded by dust, mold and millions of other microscopic foreign proteins everyday. Under normal conditions, the immune system offers protection from these foreign proteins, called antigens, by eliminating them.
The immune system accomplishes this by manufacturing other proteins called antibodies, which are the primary weapons used to eliminate the antigens. Normally, the immune system operates in a harmonious manner to eliminate these foreign invaders and keep the horse disease free.
Occasionally, however, the immune response is blown out of proportion and completely overreacts to a stimulus or antigen. This response, or hypersensitivity, is also called an allergy.
Allergies can range from a mild, disagreeable skin reaction to a life-threatening reaction within the cardiovascular or respiratory system. Everything from molds and spores in the air and grain to insect bites can trigger an allergic reaction.
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.
Symptoms: Heaves is one of the most common types of allergy observed in horses.
The common clinical signs associated with heaves include a chronic cough and exercise intolerance. Horse often exhibit an increased respiratory rate, and a nasal discharge may be present. Wheezing may be audible, and over time, horses will develop a 'heave line' between the flank and thorax. Severely affected horses will suffer weight loss and appear unthrifty.
Cause: Pollen, dust or molds result in allergic bronchitis that is similar to asthma in people.
Treatment: Heaves is a management-related disease, so the treatment is to remove the cause.
For example, remove the horse from the stable and turn it out to pasture. Most horses will respond quickly to feed and bedding.
Changing bedding to shavings or shredded paper will often be helpful. In severe cases, removal of bedding material and placing the horse on rubber mats may be necessary. Soaking the hay in water for up to five minutes will help remove some of the dust and spores.
Also, store your hay in a separate building or, at the very least, away from the horse. If the horse is severely affected, remove all hay from the diet. Feeding a complete or pelleted ration may be beneficial.
Your veterinarian may recommend medical therapy, which could include corticosteriods, although long-tern treatment may be required.
Taken From Horse And Horse