Food allergies in dogs are not as common as you might think because they only account for about 10% of all allergies in dogs.
The hard part is to diagnose a food allergy. While some dogs may vomit or get diarrhea sometimes, they mostly develop itchy lesions or hives, and with an itchy dog it is very difficult to tell the difference between food allergy, inhalant allergy, and the effect of fleas, ticks, or mites. Sometimes food-allergic dogs will have additional symptoms such as anal itch, flatulence, sneezing, asthma-like conditions, behavioral changes, or seizures, but it is rare. One helpful clue is that most food-allergic dogs have problems all year long, not just during a spring or other season.
Food Allergies and Food Intolerance
The term food allergy is commonly used, but not every food-induced problem is caused by an allergic reaction, but can be a case of food intolerance. Some dogs can’t tolerate milk, soy, or preservatives, and that has nothing to do with allergy. The most common causes of of food allergies are corn, wheat, soy, chicken, beef, pork, fish, whey, milk, eggs, and preservatives.
Changing brands or types of dog food may not eliminate the source of the problem since most commercial dog foods contain some of the above mentioned ingredients. This only works if you are lucky and change to a different brand or type of food that does not include the allergy causing ingredient.
Hypoallergenic Diet Trial
The best way to prove a food allergy is with a hypoallergenic diet trial. This is done by feeding a diet for a minimum of 4 weeks that the dog will not be allergic to. If the dog’s condition improves, this confirms that the problem was diet related. If the dog’s condition does not improve, the problem is most likely not food related. The dog does not need to stay on the hypoallergenic diet forever, only to determine if the problem is in fact diet related so that further action can be taken.
For the hypoallergenic diet trial to work, the food must be homemade, fed for at least 4 weeks, and contain ingredients the dog has never eaten before. A suitable protein source can be mixed with rice or potatoes to create a hypoallergenic meal. A diagnosis cannot be made by switching from one commercial diet to another. Once the allergy causing ingredient has been determined, most dogs with adverse food reactions can be maintained with a commercial hypoallergenic diet. Such diets may contain lamb, rabbit, venison, etc, because those are protein sources that many dogs have not eaten as part of their regular diet before. The important thing to understand is that we, including our dogs, can’t be allergic to something we’ve never eaten before, not that some foods are less allergic than others. If a dog has never eaten lamb, he won’t be allergic to it, but if he already had it in his diet in the past, he can become just as allergic to the lamb as to the beef or chicken. In this case the lamb would no longer be suitable for the food test.
During the trial, only hypoallergenic foods and fresh, preferably distilled water must be fed. Absolutely nothing else can be fed, such as treats, vitamins, chew toys, or even flavored heart worm preventative tablets. The dog also needs to be denied access to food and feces of other pets in the household. All this may seem somewhat tough to get accomplished, but it is the only reliable way to identify adverse reactions to foods. There are other alternatives available by Veterinarians that may seem a lot easier, but they can be expensive and can be misleading because the results are not always accurate.
While the dog is experiencing food allergies or food intolerances and is likely to by itchy and have inflamed areas on his body, you can comfort him with a cool bath and using a natural calming and soothing dog shampoo to provide relief. A natural anti-itch spray with a cooling effect can be applied several times a day. While the spray easily penetrates fur to get to the skin, a natural anti-itch gel with a cooling effect can be applied to hairless areas such as abdomen, armpits, muzzle and paws to calm and soothe inflamed areas.