allergies in dogs

An allergy is a state of over-reactivity or hypersensitivity of the immune system to a particular substance called an allergen. The allergen protein may be of insect, plant or animal origin. Exposure to the allergen, usually on multiple occasions, sensitizes the immune system, and a subsequent exposure to the same or related allergen causes an over-reaction.
What are the symptoms of allergies in dogs?
In the dog, the most common symptom associated with allergies is itching of the skin, either localized (in one area) or generalized (all over the body). This can manifest as ear infections, "hotspots", redness on the abdomen, or chewing at the feet or other areas.
How common are allergies in dogs?
Unfortunately, allergies are quite common in dogs of all breeds and backgrounds.
What are the common allergy-causing substances (allergens)?
A very large number of substances can act as allergens. Examples of common allergens are pollens, mold spores, dust mites, shed skin cells (similar to "pet allergies" in humans), insect proteins such as flea saliva, and some medications. Food allergies are also very common.

What is a Food Allergy and how is it treated?
Food allergy or food hypersensitivity can develop to almost any protein or carbohydrate component of food. It most commonly develops in response to the food of a particular food origin; dairy products, beef, wheat gluten, chicken, chicken eggs, lamb, and soy are commonly associated with food allergies in dogs. Food allergy can develop at almost any age. Food allergy may produce any of the clinical signs previously discussed including itching, digestive disorders, and respiratory distress. A dog may have multiple types of allergy, such as both food allergy and Atopy.
Food allergy does not respond well to corticosteroids or other medical treatments. Treatment requires identifying the offending component(s) of the diet and eliminating them. The recommended way to identify food allergy is through a simple blood test. Then a diet can be specifically tailored to your dog's individual needs. If allergy testing is not possible, an elimination diet using a hypoallergenic diet can be given. Because it takes at least eight weeks for all other food products to be eliminated from the body, the pet must eat the special diet exclusively for eight to twelve weeks. If a positive response improvement of your pet's clinical signs occurs, your veterinarian will advise you on how to proceed.
It must be emphasized that if the diet is not fed exclusively, it will not be a valid test. All table food, teats or flavored vitamins must be discontinued during the testing period.

The symptoms of allergies can be confused with other disorders, or occur concurrently with them. Be prepared for your pet to receive a full diagnostic evaluation to rule out other causes. If an allergy is diagnosed, your whole family must follow your veterinarian's advice very closely in order to successfully relieve your pet's discomfort.