Pets experience allergies to pollen, flea bites and even food. With a food allergy, the immune system reacts adversely to one or several ingredients in the animal's diet. Some pets become hypersensitive when they develop an abnormally intense reaction to certain ingredients.
Allergens usually come from meat-protein sources (such as poultry, beef, pork, lamb or fish) or from grain-protein sources (such as corn, wheat, soybeans or rice). Contrary to what many people think, a food allergy isn't a reaction to a new ingredient in the diet, but as with other types of allergies, a reaction to ingredients the pet's immune system recognizes. Allergic reactions in pets usually result in an uncontrollable itch on one part of the body or all over. Food-allergic pets tend to scratch intensely at their ears or lick at their anal areas. On occasion, a food allergy appears as gastrointestinal distress, such as vomiting or diarrhea, or respiratory distress, including sneezing or breathing difficulty. Risk Factors and Detection
There are no known risk factors for food allergies. However, food allergies are the second most common skin disease in cats. Unlike other types of allergies, food allergies don't target a specific breed or gender.
If general allergy symptoms develop in a pet younger than six months or older than six years, your veterinarian will likely investigate a food allergy over other allergies, especially during the winter months when seasonal inhalant allergies are a less likely cause. Your vet may also suspect a food allergy if the itching persists all year long or your pet doesn't respond well to treatments (such as steroids) for inhalant allergies.
Detecting a food allergy in your pet requires time and discipline. Your veterinarian can use intradermal skin testing or blood tests to detect inhalant allergies in pets. One way to detect a food allergy is through elimination diet trials using hypoallergenic foods.
Hypoallergenic foods must not contain any meat or grain proteins from your pet's usual diet. Many different hypoallergenic diets are available. Always work with your veterinarian to determine if your pet has an allergy of any kind.
Most pet owners continue feeding the hypoallergenic diet once their pet's symptoms resolve. But, if you want to identify what caused the allergic reaction in your pet, you can conduct a provocation diet trial. Work with your veterinarian to reintroduce meat and grain protein ingredients from the pet's original diet, one ingredient at a time, to see if the itching and scratching return. The trial for each ingredient may last up to 10 days, but in most pets, clinical signs of an allergy return within two days. Prevention and Treatment
Once you identify an allergen, eliminate that ingredient from your pet's diet or just continue feeding hypoallergenic foods. But keep in mind that a pet who is predisposed to food allergies may develop reactions to the new diet. If that occurs, you'll need to conduct a new elimination diet trial. In addition, a pet with allergies to one substance, whether it's fish, fleas, or grass, may have multiple allergies, which can complicate matters and require additional testing and treatment.