Many people believe their dog has a food allergy. While it is the third most common cause of allergies, behind flea bite allergies and atopy (or inhalant allergies), it only accounts for about 10% of all allergies seen in dogs. Sometimes people confuse a food intolerance with a food allergy and there is a difference. An allergy will show the characteristic symptoms of itching and skin problems while an intolerance results in diarrhea or vomiting. Food intolerances in pets would be similar to people who get diarrhea or an upset stomach after eating spicy, rich or fried foods. In fact, if your dog has an immediate adverse reaction to a new food, it is probably not an allergic reaction. It takes more than one exposure to produce an allergic reaction.
Foods most commonly responsible for allergies are beef, dairy products, chicken, lamb, fish, eggs, corn, wheat, and soy. Not surprisingly, these are the most common ingredients found in commercial dog food. The tendency to develop allergies is genetically determined. Dogs with other allergies like inhalant allergies or atopy may also be at increased risk for developing a food allergy.
The symptoms of food allergies are similar to those of most allergies seen in dogs, primarily itchy skin mostly around the face, feet, ears, forelegs, armpits and the anus. Other symptoms may include chronic or recurrent ear infections, hair loss, excessive scratching, hot spots, and self-inflicted skin trauma from excessive scratching, red bumps or papules, skin infections that respond to antibiotics but reoccur after antibiotics are discontinued. There is also evidence that dogs with food allergies may sometimes have an increased incidence of bowel movements. One study showed that non-allergic dogs have around 1.5 bowel movements per day where some dogs with food allergies may have 3 or more per day.
It can be very difficult to determine if your dog is suffering from food allergies or suffering from other allergies based simply on physical symptoms. However, there are a few signs that increase the suspicion that food allergies may be present. These are:
- recurrent ear problems, particularly yeast infections
- a very young dog with moderate or severe skin problems
- allergies year-round or if the symptoms begin in the winter
- a dog that has very itchy skin but does not respond to steroid treatment.
The best way to determine if your dog does have a food allergy is through an elimination food trial. This test consists of identifying a diet that contains foods to which the pet has never been exposed, usually one protein and one carbohydrate. Common examples are venison, duck, rabbit, potato, rice and strict feeding of this food alone for 12 weeks. You and your family must be strict and be certain that no one "breaks" the food trial by giving the dog treats or table scraps. Strict compliance with the trial is essential for proper interpretation of the results. This means no treats (including ours), rawhide bones or pig ears, no flavored medications, and no flavored vitamins during the trial. A food allergy is considered a possibility if the itchiness and scratching subside and your dog does not develop relapsing skin or ear infections during the food trial.
The treatment for food allergies is avoidance. Short-term relief may be gained with fatty acids, antihistamines, and steroids, but elimination of the offending food from the diet is the only long-term solution. The owner has two choices, you can choose to feed your pet a special commercially prepared diet or a homemade diet. If you choose to feed a homemade diet, then you can periodically challenge your pet with new ingredients and determine which ingredients are causing the food allergy. For example, if your dog's symptoms subsided on a diet of rabbit and potatoes, then you might try adding beef for two weeks. If your pet shows no symptoms, then try chicken for two weeks. If your dog starts to show symptoms, then it could be assumed that chicken was one of the things the pet was allergic to. The chicken could be withdrawn and after the symptoms cleared up, a different ingredient could be added and so on until all of the offending ingredients were identified. A diet could then be formulated that was free of the offending food sources.
As always, consult your Vet where the health of your pet is concerned.