Food allergies are among the most common types of allergies in dogs. In order to develop an allergy, a dog must have a genetic predisposition, but environment can also be a factor. Food sensitivities can also sometimes be mistaken for allergies, and they can cause pretty unpleasant symptoms, too.
Following behind flea and environmental allergies, food allergies are the third most common cause of dog allergies, according to Dr. Robyn Jaynes, a veterinary expert who works with PetSmart. Allergies occur when the immune system overreacts to a specific protein in a food. This causes the body to make antibodies to combat the offensive food. Food allergies can cause symptoms including chronic ear inflammation, vomiting, diarrhea and licking the paws or other areas due to itchiness.
New Foods, or Just Undiscovered Allergens
The most common allergens include beef, chicken, lamb, pork, rabbit, fish, dairy, eggs, soy and wheat. Dr. Susan Wynn notes that dogs can be allergic to more than one ingredient. She says that, to develop allergies, a dog must have a genetic predisposition. Environment can contribute. Because dogs are born with a predisposition, they may react to a new food because it hadn't been been given before -- so there was no knowledge of the predisposition.
Allergies vs. Sensitivities, Plus Chemicals
Food allergies differ from food sensitivities. Allergies are immune-system-based, whereas sensitivities aren't. But they still cause suffering. Dog parents may witness food sensitivities if a food is offered, and it causes symptoms. New foods in large quantities can cause tummy troubles; when offering new foods, doing so gradually helps minimize this risk. In some cases, it isn't even the ingredients, but a chemical, additive or contaminant in the food, the Dog Food Advisor website says. These can cause allergies or sensitivities.
Rotation and Elimination
Current foods can sometimes actually cause allergies. Dr. Wynn says dogs who eat the same type of food for long stretches of time can develop allergies. Rotating known foods can help avoid this. To diagnose a food allergy, Dr. Wynn recommends, try an elimination diet. This involves removing all current foods from the diet, and replacing them with one food the dog's never eaten before. Over a few weeks, new foods are added gradually and the dog is monitored for symptoms.