Does your dog scratch constantly, even when it’s not flea or “allergy” season? Do they suffer from frequent skin or ear infections, or have occasional bouts of stomach sensitivity? Do they lick or chew on their feet frequently? If so, these symptoms could point to an issue many dogs face — food allergies.
Food allergies are a hot topic in the dog world. Across the internet and in pet stores, companies make claims that their grain-free and sensitive skin diets can help out your pet with their allergies. While food allergies could account for your pet’s symptoms, it is important to fully understand food allergies, how to determine if your pet has them, and what foods can actually help your pet out. Food allergies are just one of many potential causes of your dog’s problems. Other forms of allergies include reactions to flea bites and environmental allergies from grass, dust, plants, laundry detergent, perfume, and other triggers, which account for more allergy signs in dogs than those caused by food allergies. If you are suspicious that your dog has food allergies, you first need a good understanding of what food allergies are and how to tell if your pet has them in order to know how to properly deal with them!
WHAT ARE FOOD ALLERGIES?
Food allergies occur when your pet’s immune system recognizes the proteins in the food they are eating as foreign, and falsely labels them as a foreign “intruder” in the body rather than what they really are — food. The body creates an immune response to try to fight this “intruder” protein just as it would to fight bacteria or viruses your pet picks up. When the body has this reaction, the signs of food allergies can be seen in your pet. These can be both classic allergy signs or signs of gastrointestinal issues/sensitive stomach. The most common foods causing allergic reactions in dogs are chicken, beef, dairy, eggs, and fish. It is important to note that some pets may only have one sign of food allergies, while others may have all the signs listed below. Every dog responds differently, so just because your pet doesn’t have all of these symptoms, it doesn’t mean they don’t have food allergies.
Signs of food allergies:
- Chewing feet
- Rash or redness around the mouth or rectum
- History of chronic skin and/or ear infections
- Finicky appetite
- Chronic or intermittent loose stool
- Excessive flatulence
Photo by Drs. Foster & Smith Educational Staff
HOW DO I KNOW IF MY DOG HAS FOOD ALLERGIES?
There are many labs and companies that claim to have a test to identify food allergies, but none of these companies have scientific backing to indicate these tests are accurate. In fact, one of these labs was proven to be a total scam after a veterinarian submitted samples from several dogs that have no allergies and all of the tests came back with the exact same results. Don’t waste your time or money on one of these tests. The only way to know if your pet has food allergies is to put them on a Diet Elimination Trial. This is where you feed your pet a food that is known to be much less likely to cause food allergies and eliminate ALL other food during this time period in order to see if your pet’s allergy signs go away. This isn’t as simple as feeding this food for a few weeks and expecting your dog’s symptoms to end and their skin to become perfect.
HOW TO PERFORM A DIET ELIMINATION TRIAL
It is very important to maintain the food trial for a minimum of 10-12 weeks. Usually you will not notice any major change in your pet’s itching/allergy signs for the first 6 weeks. During this period of time your pet is purging tiny particles of food, allowing their immune system to cool down, and waiting on the inflammation (which was already present) to subside.
Your pet cannot eat any other food, treat, snack, etc. NOTHING ELSE BY MOUTH other than the recommended food with the exception of treats that are made to go specifically with that diet. It is well documented that if a pet gets into one item it is allergic to during the course of the elimination period, they may itch for another 2-4 weeks. So if your pet gets just one bite of something they are allergic to every few weeks you may completely miss seeing any improvement and the diet elimination trial will have been wasted.
PITFALLS & MISTAKES
- NO table foods, scraps, rawhide chews, or anything that has any “flavor” or protein source.
- NO pill pockets. The canned version of your specific food can be used to make “meatballs” to give medications. You can use a lid or plastic wrap and keep the wet food in the fridge to keep it from spoiling so that one can may last for an extended period of time.
- Visitors and children may have a hard time understanding why your pet can’t just have one bite of whatever they are eating. It’s best to put away dogs with food allergies during meals to make sure there is no chance your pet is getting table scraps.
- If you have other dogs in the household, put them on the same diet or have them separated at feeding times and make sure the bowls are put up after they are done (even licking an empty bowl can trigger symptoms.)
- If you have cats in the household, put the cat food and litter box out of reach. Feces contains protein and can cause allergy signs in your dog if ingested.
- All pets should be kept in a fenced in yard. Free roaming is not only dangerous for pets, but you can’t control if your dog is getting into someone’s trash or food scraps if they are free to roam.
Many pets have allergies to more than just one thing, such as fleas and environmental allergies. Dogs with food allergies that also have environmental allergies may have year round allergy signs that are worse during the spring and summer when their seasonal environmental allergies flare up. Always check your pet closely for fleas and have your vet double check if significant allergy symptoms appear out of the blue.
If your pet’s allergy signs go away. You can confirm their symptoms were related to the food by offering up some of the old food or different protein source food and see if the signs return — this confirms it is food allergies. This can help differentiate from seasonal allergies coincidentally changing around the time of the diet elimination trial.
Prescription Diets: Prescription hypoallergenic/hydrolyzed diets are by far the BEST for dogs with food allergies and the best for a Diet Elimination Trial. Hydrolyzed diets have had the proteins broken down into tiny microscopic pieces that are so small the body’s immune system does not recognize them. These diets can be purchased from your veterinarian. Hill’s Science Diet Z/D, Royal Canine Hydrolyzed Protein HP, and Purina Pro Plan HA Hydrolyzed are great prescription hydrolyzed diets.
Limited Ingredient Diets: Many dogs do good on a Limited Ingredient Diet with one novel protein source. Prescription diets can become very pricey for large dogs and this is a good alternative to try if cost prohibits you from prescription diets. Many dogs get better on these diets but aren’t 100% relieved, and owners may elect to move up to a prescription diet for better resolution of signs. Novel proteins are ones that cause reactions in very few dogs. The BEST protein sources are duck or venison, and these are the only protein sources I recommend for food allergic dogs. Many duck or venison varieties also contain chicken, beef, or fish or are contaminated with proteins from other diets made in the same factories. This is why it is important to use a Limited Ingredient Diet with a single protein source in the ingredients. The prescription hydrolyzed diets are rigorously controlled to prevent this. Natural Balance (my personal preference), Merrick, Acana, and several other companies have these products.
Grain Free Diets: Many owners are under the assumption that their dog’s food allergies are grain allergies based on marketing from certain dog food companies and from reports from friends or groomers or articles they read online. This is VERY uncommon, and gluten allergies are even more rare in dogs. Many owners believe this and report that when they swapped to a grain free diet all the allergy signs improved. Usually what happens is the protein source in the diet changed which is the actual reason the signs improved, not the removal of grains in the diet.
(FYI — golden retriever owners: many grain-free diets are currently being investigated by the FDA for causing dilated cardiomyopathy in golden retrievers.)
Food allergies can account for your pet’s itching, scratching, ear infections, and sensitive stomach. The best way to determine if your pet has food allergies is with a Diet Elimination Trial. Your veterinarian can help guide you in performing this test for your pet and provide you with a prescription diet to use, if needed. If your pet has the signs of the food allergies mentioned above, all their issues could be resolved simply by feeding them the right food!
Spencer Mills, DVM
Have you done the Diet Elimination Trial? Tell us your experience in the comments!
Dr. Mills is a veterinarian and avid dog lover who is dedicated to helping further educate pet owners on all things health related for their four-legged companions. In addition to practicing in his local vet clinic, Dr. Mills has a mobile house call veterinary business, works with numerous local shelters and rescue organizations, and is in the process of opening an emergency veterinary clinic giving him a wide array of experience in the veterinary field.