Causes of Canine Allergies
An allergy is an acquired and exaggerated defensive reaction by an animal’s immune system to something that it perceives as being foreign and potentially dangerous. The offensive substance is called an “allergen.” Acquired allergic reactions, also called hypersensitivity reactions, develop over time. The first exposure to the offending allergen stimulates the dog’s immune system to go into a state of readiness. This includes producing antibodies to that specific allergen. Subsequent exposures trigger a full-blown, complex, highly regulated immune response, because the cells of the immune system recognize the allergen and have been primed to find and destroy it.
There are four main categories or causes of allergies in dogs:
Contact allergies are triggered by a dog’s repeated exposure to some irritating substance that comes into direct physical contact with its skin. Common canine contact allergens are chemicals in household cleaners, shampoos, flea collars, fertilizers, insecticides, medications, natural and synthetic clothing or furniture fibers, plastics, seasonal pollens, trees, bushes, grasses, weeds, flowers and other plant products. Contact allergies usually are most noticeable to owners on areas where their dog’s skin is not well-protected by hair, like the nose, feet, groin, belly and between the toes.
Injection Allergies, of which the most common are caused by flea bites. In a nutshell, dogs with this condition become hypersensitive to the saliva of fleas, ticks or other blood-sucking external parasites. Flea bite allergies trigger an immune reaction to the fleas’ saliva, which causes intense irritation and itchiness and can increase the risk of secondary bacterial infections and localized hair loss at the bite site.
Inhalant Allergies Many dogs develop allergies to environmental substances that they inhale. Common culprits include cigarette and cigar smoke, fireplace smoke, seasonal pollen from weeds, trees, grasses and other plants, and many other things. Inhalant allergies are second only to flea bite allergies in terms of frequency in dogs. The severe skin itchiness and irritation associated with inhalant and some contact allergies is called “atopy.” Many contact and inhalant allergies, in both dogs and people, are casually referred to as “hay fever.”
Food allergies can develop from hypersensitivity reactions to almost anything in a dog’s diet. Common canine food allergens include beef, dairy products, corn, wheat, eggs, chicken, lamb and soy.
Preventing Allergies in Dogs
The best way to prevent allergic reactions in dogs is to keep them from coming into contact with, eating, inhaling or otherwise being exposed to whatever allergen is causing their hypersensitivity. For example, flea bite allergies are best prevented by removing the allergen – fleas – from the dog’s body and immediate living environment. There are a number of good commercial products to help owners prevent or resolve flea infestations. Owners of dogs with flea allergies should consult with their veterinarian about the best approach to control the problem. To prevent the symptoms of hay fever, owners should keep their dogs away from whatever seasonal allergen is causing the problem, to the extent that they can. Food allergies can be prevented once the culprit in the dog’s diet is identified. This can be done through a strict ingredient elimination diet supervised by a knowledgeable veterinarian. Many of the newer kibbles contain novel protein sources, such as venison, bison, duck and fish, which can be extremely helpful for dogs that are allergic to more common protein sources, like chicken, beef or lamb.
Canine allergies can be difficult, but not impossible, to diagnose and manage.