Allergies & Atopy

Information About Allergies & Atopy

Symptoms of allergies

Dogs with allergies may show the following symptoms:

Chewing on feet
Rubbing the face on the carpet
Scratching the body
Recurrent ear infections
Hair loss
Mutilated skin
 In reality, the dog will seldom have these signs. Instead, he will have a mild to severe itching sensation over his body and maybe a chronic ear infection.

A dog who is allergic to something will show it through skin problems and itching, i.e., pruritus. It may seem logical that if a dog is allergic to something he inhales (atopy) like certain pollen grains, he will have a runny nose; if he is allergic to something he eats (food allergy) such as beef, he may vomit; or if allergic to an insect bite (urticaria or hives), he may develop a swelling at the site of the bite.

In addition, allergic dogs will often chew on their feet until they are irritated and red (the feet are the only place dogs have sweat glands and these become inflamed with allergies). They may rub their faces on the carpet or couch, or scratch their sides and belly. Because the wax-producing glands of the ear overproduce as a response to the allergy, they get ear infections. Bacteria and yeast often "over grow" in the excessive wax and debris.

The skin lesions seen in an allergic dog are usually the result of him mutilating his skin through chewing and scratching. Sometimes there is hair loss, which can be patchy or inconsistent over the body leaving a mottled appearance. The skin itself may be dry and crusty, reddened, or oily depending on the dog. It is very common to get secondary bacterial infections of the skin due to these self-inflicted lesions. Such infections may be treated with antibiotics.
Chewing on feet

Chewing on feet



Allergies2

Allergies3

Allergens

When a dog is allergic to something, his body is reacting to certain molecules called ‘allergens.’ These allergens may come from:

  • Trees
  • Grass
  • Weed pollens
  • Fabrics such as wool or nylon
  • Rubber and plastic materials
  • Foods and food additives such as individual meats, grains, or colourings
  •  Milk products
  • House dust and dust mites
  • Flea bites

The body’s response to an allergen

The reason that all these allergens cause itchy skin is that, simplistically, when allergens are inhaled, ingested, or come in contact with the dog’s body, they cause the immune system to produce a protein referred to as IgE. This protein then fixes itself to cells called ’tissue mast cells’ that are located in the skin. When IgE attaches to these mast cells, it causes the release of various irritating chemicals such as histamine. In dogs, these chemical reactions and cell types occur in appreciable amounts only within the skin.

Genetic factors and time influence allergies

Remember that dogs must be exposed to the allergen for some time before the allergy develops. Exceptions may occur such as an allergy to insect bites, which may develop after only a few exposures. The dog’s body must learn to react to the allergen. It is a learned phenomenon of the immune system that is genetically programmed and passed from generation to generation in several breeds. Allergies are especially common in certain terriers such as the Scottish, West Highland White, Cairn, and Wire Haired Fox; Lhasa Apso; and larger breeds such as the English and Irish Setters, Retrievers, and the Dalmatian. Allergies are also well documented in the Pug, Miniature Schnauzer, and English Bulldog.

In pets, allergies usually start to develop between one and three years of age. They may start as late as age six or eight, but over 80% start earlier. To make matters worse, as the animal ages, it usually develops allergies to additional things and the response to any one allergen becomes more severe.

Diagnosing allergies

A dog who is allergic to something will show it through skin problems and itching, i.e., pruritus. It may seem logical that if a dog is allergic to something he inhales (atopy) like certain pollen grains, he will have a runny nose; if he is allergic to something he eats (food allergy) such as beef, he may vomit; or if allergic to an insect bite (urticaria or hives), he may develop a swelling at the site of the bite.
Allergy testing (intradermal or blood testing)A definitive diagnosis of an allergy and determination of exactly what the animal is allergic to can be made in two ways:

  1. Eliminating things individually from the animal’s environment until the culprit is isolated (the method most often used when food allergies are suspected)

In some instances, it may not be necessary to determine the exact allergen causing the problem. For example, a dog may start chewing his feet, scratching his sides, and rubbing his face on furniture every year for three weeks during the same month. These are often the signs of a seasonal allergy to something such as ragweed or tree pollen. In this case, the veterinarian may choose either tablets and/or a single injection that will suppress the allergy for the 3-4 weeks necessary when that allergen is in the environment. After a short treatment period, the animal is back to normal and only has to wait until the following year when he or she will be returned to the veterinarian with the same problem.

So now you know the basics of canine allergies. If you have more specific questions about the different types of allergies, how to diagnose them or treat them, we encourage you to read the other articles in this section. They provide the newest and most up-to-date information on this very common problem.

Treating allergies Avoidance

This can be a very important part of managing atopy. While it may be impossible to completely eliminate all of the offending agents, many can be reduced with minimal effort on the part of the owner. For avoidance therapy to have any benefit, the offending agents must be identified through intradermal skin testing. Avoidance is rarely a complete treatment in itself, but is used in conjunction with other treatments.

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