We all know someone who has an allergy to some type of food, whether it’s peanuts, shellfish, yeast (in bread), dairy products, etc. But you may be surprised to learn that food allergies account for approximately 5 to 10% of allergy cases that we see in dogs and cats.

By far, the majority of allergies we see in pets are related to pollens (from grass, trees, and weeds), dust, and dust mites, molds and mildew, and fleas. Typically, these allergies are seasonal in nature, just like in people. Allergies from these sources usually cause hair loss, skin irritation, skin infections as well as frequent biting, scratching, chewing, licking and rubbing. Yet pets with food allergies will often exhibit the same symptoms and the same skin condition. To complicate matters, at least 50% of pets with food allergies also have an allergy to either pollens, dust, molds, mildew or fleas.

So, how do we know if a pet has a food allergy? I’ll address that soon, but there’s one more ‘wrinkle’ that confuses the situation even further. In addition to food allergies, we also see “food intolerances”. So, what’s the difference? Food intolerances do not involve the body’s immune (natural defense) system and they usually result from food additives, such as sulfites, MSG and food dyes. Food allergies, on the other hand, do affect the body’s immune system and result from a reaction to a protein in the food.


DOGS: * Beef, Wheat, Chicken, Lamb, Soy, Corn, Eggs, and Dairy products (often in the form of Whey protein), account for ~95% of food allergies in dogs

  • If you commit to a food allergy trial (details below), then definitely avoid these ingredients!
  • Oatmeal, pasta, pork, fish, turkey, rabbit, rice flour, artificial food additives and food preservatives can also cause food allergies
  • 80% of dogs are allergic to only 1 or 2 food sources.

Dog Breeds often affected: Cocker Spaniels, Springer Spaniels, Labrador Retrievers, Collies, Poodles, Schnauzers, Shar-Peis, Westies, Boxers, Dachshunds, Lhasa Apsos, German Shepherds, Golden Retrievers and Dalmatians

Food allergies are always suspected when we see a very itchy dog that’s free of fleas and mange. The typical itchy areas include the ears, the feet, the armpits, the face, and the groin area. Many dogs also have gastrointestinal problems such as occasional vomiting, diarrhea or an increase in the frequency of bowel movements. When pets have year-round skin and/or ear problems, we always have a stronger suspicion of a food allergy.

CATS: *Beef, dairy products, and fish account for 90% of food allergies

* Pork, chicken, rabbit, lamb, eggs, clam juice and cod liver oil are other potential sources of food allergies

Cat breeds more likely to be affected: Siamese and mixed-Siamese


By far the most common mistake pet owners make when they think their pet may have a food allergy is to simply purchase a new dog or cat food without considering what may actually be causing a food allergy … or they assume that their pet must be allergic to corn or some grain. So they go to their local pet store and switch to a grain-free diet, or an “all-natural” diet (I’m not even sure what an “all-natural” diet even is … but it sure sounds great, doesn’t it !?), or any diet that sounds like it’s better than what they’re currently feeding their pet.

But all too often, the majority of pet owners are doing nothing more than just trading one brand of pet food for another brand of food. They are simply switching “labels”, but they don’t avoid the ingredient that causes the food allergy. Now that you know what pets are most likely allergic to, you can understand why this seldom works. Avoid the trap of simply changing the diet just because you feel compelled to “do something”!


With allergies to pollens, fleas, house dust, etc, we can perform skin tests (like a “patch test” in a person) or blood tests to find out specifically what pets (or people) are allergic to. Unfortunately, there’s no reliable skin test or blood test that can help us identify what food a pet may be allergic to. So, when we suspect a food allergy, we want to place that pet on a “food allergy trial”, which means that we need to feed a special diet in which we avoid any protein/food source that the pet has eaten before.

We now have a variety of commercial diets designed to “test” for a food allergy, but there is no single diet that works for all allergic pets. Even under the best of circumstances, only 80-85% of pets will respond favorably to a food allergy trial. Frustrating, isn’t it?

Commercial diets for food allergies are divided into 3 categories:

  1. Grain-Free diets – these diets have become incredibly popular recently, and many pet owners notice an improvement when they switch their pet to grain-free. But, DO NOT fall into the trap of thinking that all pets that are itchy have an allergy to grain! Understand that we still see far more environmental allergies than food allergies.
  2. Novel (“new”) protein diets – the idea is to offer a food that the pet hasn’t been exposed to before such as rabbit, venison, or kangaroo. Salmon and white fish can be good choices … but ONLY if your pet has never eaten them before in any form (canned tuna, scraps off your dinner plate, etc.). Many veterinary dermatologists recommend Natural Balance as an excellent commercial diet.
  3. Protein Hydrolysate diet – these diets are made by chopping up the proteins in the diet to tiny “peptides” which the body presumably cannot detect, and therefore should not have an allergic reaction to. However, some pets will still show allergies to these foods, so we do not recommend using them during a food allergy trial.


Home-made diets have proven to be quite successful in many cases, too. But it takes a very dedicated pet owner since it is imperative to prepare the same home-cooked diet for a minimum of 8 weeks. Read that again: A minimum of 8 weeks! The best choice is a combination of a carbohydrate such as sweet potatoes, peas or pinto beans (and DO NOT add butter, milk, bread !) with a novel protein such as rabbit, venison, kangaroo (these can often be ordered online). As mentioned earlier, salmon and white fish (such as tuna) can only be considered if your pet has not eaten them before.

If you don’t have access to one of the novel proteins, then a diet consisting exclusively of potatoes, peas or pinto beans is satisfactory. While this diet doesn’t seem very appealing or nourishing, remember that the whole purpose of the diet is to try to identify if the pet has a food allergy over a mere 2 to 3 months.


Since cats can be fussy about what they eat, cooking up a home-made diet for a kitty can be a big challenge, but there are several choices of proteins. Lamb, ostrich, rabbit, venison or duck have all been used with good success. They can be fed alone, or they can be blended with potato or rice. In general, we recommend a commercial food allergy diet for cats since they can be so finicky.

The Biggest Challenge to a Food Allergy Trial: HOW COMMITTED ARE YOU?

Once we begin a food allergy trial, these pets can eat absolutely NOTHING ELSE FOR 8 to 12 WEEKS except for the special diet! This means that no other foods, treats, flavored chew toys, or flavored heartworm preventives should be given to your pet during the trial.

Please understand: If a pet owner should decide to cheat/stray at all from the recommended diet, it will defeat the whole purpose of the food trial! So either you’re committed … or you’re not. There’s no in-between. And only you can decide.

Other important features for you to follow …

For DOGS on a Food Allergy trial:

  1. Look back on the first page again. I list the Top 95% sources of food allergies in dogs. If we suspect a dog has food allergies, doesn’t it make sense to avoid these ingredients ??? Of course, it does. You must become an avid reader of dog food labels.
  2. NO !!! Cheese (no dairy !) – Bread – Peanut butter – Rawhide bones – Milk bone type treats – Greenies – Poultry or beef favored toothpaste – Flavored chewable Heartworm tablets
  3. During a trial, we strongly advise switching your dog to a Topical Heartworm product (we have Revolution and Advantage Multi) in order to avoid animal protein and soy in the chewable tablets.
  4. If in doubt, leave it out!
  5. Confine your dog to leash walks to prevent them from wandering on their own and finding other food sources.
  6. If you’re giving medication to your dog, you can use VEGAN marshmallows (available online or at Whole Foods Market) to hide the pills.
  7. If you brush your pet’s teeth, use a “vanilla mint” flavored pet toothpaste. Do Not use poultry flavored.
  8. Keep your dog out of the kitty litter!
  9. Prevent your dog from licking the food dish of another dog or cat.
  10. Re-read #1 through #9 … then read it again

For CATS on a Food Allergy trial:

  1. Do not let your cats go outdoors since they can often find other food sources.
  2. Prevent your cat from licking the food dish of another cat or dog.

Skin infections caused by bacteria and/or yeast can cause considerable itching, so it’s important to watch for red or irritated areas of skin. We need to treat these skin infections to help accurately gauge the success of a food allergy trial.

We typically can determine within 8 to 12 weeks if your pet has a food allergy, but remember that 10- 15% of pets that have a food allergy may not respond to a dietary trial. That’s one of several things that make coping with food allergies so frustrating.

If we get a noticeable improvement, we can then try to find the cause of the allergy by introducing individual proteins or sources of meat every 2 weeks to try to identify what triggered the allergic reaction. We’ll start by introducing beef, chicken, grain or dairy products, then (if necessary) other possible ingredients to find what actually caused the problem. If we can identify the food that’s causing the problem, then you’ll know what to avoid feeding your pet. Of course, many clients are happy to keep their pet on the new diet and may decide that it’s not worth it to find out what their pet is allergic to.

Food allergies can be a challenge to diagnose, but a committed, disciplined and dedicated pet owner will certainly find a way to stick with the diet plan. The reward for your pet’s comfort can be well worth the effort.

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