Food Allergies in Dogs
Adverse reactions to food in dogs are not as common as people think. Currently they are only the cause of about 1 - 5% of all skin reactions, yet, they can be up to almost 29% in chronic/long term gastrointestinal cases (vomiting, diarrhea, gas). Any ingredients in a diet can be the culprit.
Signs of a food allergy vary in dogs; some can have them all, while others may only show a few. These signs can be non-seasonal itchiness of the feet/armpits/groin, self-induced injuries (chewing/biting of skin), inflammation of the skin (pink/redness), crusting/darkening of the skin, ear infections (which sometimes is their *only* symptom), yeast/bacterial skin infections and then gastrointestinal signs like vomiting or diarrhea.
It is important to give your veterinary team a detailed dietary history going as far back as possible so they can try and figure out any potential causes to the symptoms present in your dog. This will include any commercial foods, cooked foods, treats, flavored medications and supplements. Unfortunately, sometimes we never find out what the inciting cause is and we have to do our best through trial and error to eliminate the dog’s discomfort.
According to board-certified veterinary nutritionists, blood and saliva testing are unfortunately not reliable methods for finding out the culprit of your dog’s symptoms, if they are in fact related to food. So this will require your Veterinarian to likely recommend an elimination diet trial. The elimination diet trial is one that avoids all proteins that have been fed before and at times any that might be similar at the molecular level to a previously fed protein (e.g., not selecting bison in a beef allergic pet). Such a diet is the best and most accurate way to diagnose an adverse reaction to a food or ingredient. Failure of symptoms to improve once on an elimination diet trial (after a few days for gastrointestinal signs & up to three months for skin signs) may show that there is no underlying food reaction.
There are three options right now to choose from when going with an elimination diet trial (again, it’s all trial and error!) and they include: commercial novel protein diets, commercial hydrolyzed protein diets and homemade, fresh food recipes.
Commercial novel protein formulas use different types of animal and carbohydrate sources that the pet may not have been exposed to (e.g., venison, kangaroo, rabbit). They can be used depending on the accuracy and thoroughness of the diet history. If there is a potential for past exposure then they likely won’t be recommended by your Veterinarian. Sometimes this can be tricky especially if you have a rescued dog without a known history, especially if they are coming from a different country! Some animal proteins are common in certain aspects of the world, like kangaroos in Australia, then they are in North America.
These diets should also come from your Veterinarian as any pet store products run the risk of contamination from previous formulas produced in the same processing plant. The veterinary prescription diets are a much lower risk as these companies have the funds to securely run many, different types of food through their plants or have separate plants all together for their special formulas, eliminating the risk.
Commercial hydrolyzed protein formulas contain protein sources that have been broken down into small enough molecular pieces to prevent an allergic reaction. But, these diets are not 100% guaranteed as they can still contain some intact protein, however, they are a great option if there is little to no diet history available. They are complete and balanced formulas with minimal ingredients and are only available through your veterinary clinic. These are more expensive foods because of the science involved in creating them.
Homemade recipes are great options but they tend to be time-consuming and potentially expensive. So if you are financially committed to doing this, and have the time, then this is a viable option. The recipe does not have to be complete and balanced for the short-term diet trial (a few weeks up to three months). But, if you are going to feed a home-prepared recipe for longer than three months then you will need to provide supplementation. The advantage of using a homemade diet is that it will not contain anything except the novel protein and carbohydrate sources, and no other additives, flavors, etc.
Joy Food has simplistic, cooked recipes that might be helpful if feeding commercial foods is the problem (and sometimes it is). For example, their turkey meal contains: turkey, rice, cauliflower, broccoli, carrots, apples, flaxseed, fish oil, tumeric and Joy Complete Nutrition supplement. We are a Connecticut-based food delivery subscription service where you can choose your frequency and they send your dog’s meals!
It's important to remember that no other food items can be fed during the diet trial; avoid any other treats, flavored medications, supplements, etc, unless otherwise directed by your Veterinarian. Rapid response can be seen in days with dogs experiencing gastrointestinal signs. The diet trial has to run a minimum of four to eight weeks and ideally for 10-12 weeks for skin reactions. It is also a good idea to make sure that your dog is on, or has been given, medications to treat any underlying secondary infections (i.e., bacterial/yeast) and parasite prevention (ticks, fleas) to rule them out as these can also cause skin reactions. Any worsening of signs should be reported immediately to your veterinary team.
After managing the symptoms of your dog (pending that they have been doing very well on the recipe/diet), you can consider an ingredient challenge to find the offending foods. This can be challenging and is often rejected by people given the potential for recurrence of signs as quickly as within days. No one wants to run the risk of their dog becoming sick or experiencing painful symptoms again, and who could blame them! If the diet (and any other therapies your Veterinarian recommends) is managing clinical signs, then ideally you would continue the commercial diet or start supplementing the homemade diet with an appropriate product. If signs recur or a new reaction develops then a new food may need to be fed.
Although food allergies are not as common as one would think, they do exist and are important to investigate. If your pet is experiencing any of these symptoms, please discuss the options with your Veterinarian and they can come up with a personalized treatment plan.
Article by Kelly Gredner RVT, VTS (Nutrition)
Kelly has been a Registered Veterinary Technician for 14 years with the last five of them being as a Nutrition Technician, specialized through the Academy of Veterinary Nutrition Technicians (AVNT). Her interest in nutrition grew as the years went on and she loves being able to help beloved pets, one bowl at a time. She currently resides in Toronto, Ontario with three cats and works full-time in a small animal practice.