It may surprise you to discover that dogs, like people, can develop allergies, whether it be seasonal, skin, or food-related. While the first two examples are relatively common, food allergies are not quite such a normally occurring phenomenon. That said, for dogs that do have food allergies, such problems can seriously hamper their ability to live happy and energetic lives. 

While reactions to food may not be the most common allergies in dogs, they are still a concern that pet parents should be aware of. With that in mind, below, we’ll discuss everything you need to know about canine food allergies, so that you can spot the signs and take action before anything bad happens to your favorite pup. 

Understanding Food Allergies in Dogs

As mentioned, canine food allergies are infrequently diagnosed. In fact, according to a study entitled Overview of Food Allergy, Dr. White found the following:

Food allergies are very rare in herbivores. In this chapter, the more commonly used term food allergy will be used for all adverse food reactions. Food allergy is ~10% as common as atopic dermatitis in dogs and perhaps as common as atopic dermatitis in cats. The history is that of a nonseasonal pruritus, with little variation in the intensity of pruritus from one season to another in most cases.

The truth is that food allergies are rare. According to Web MD, only 10% of all allergy cases in dogs are related to food. The problem lies in the fact that a food allergy is often conflated with a food intolerance; and few people realize that these two gastrointestinal issues are not the same thing.  

What is a Food Allergy? 

Food allergies most commonly occur when a dog’s immune system mistakenly identifies a protein as a bacterial assailant instead of an ingestible substance. In response, the immune system reacts and causes a host of unpleasant symptoms, ranging from itchy skin to gastrointestinal problems. 

A dog’s gastrointestinal system is composed of its mouth, stomach, and intestine, and accounts for roughly 70% of its total immune system. When your dog eats, the food digests in the stomach. Large pieces are broken down by stomach acid into enzymes and as the pieces move down the tract, stomach acid continues to break them down into even smaller structures. The mostly-digested food moves into the small intestine where it is broken down into amino acids, which will then be absorbed via enterocytes. According to Modern Dog Magazine:

Enterocytes act as both a welcoming hostess to amino acids that they like and want, and as bouncers (door guards) for amino acids they don’t like. When a whole protein is absorbed in the intestines instead of being broken down first, the immune system reacts and your dog shows symptoms of a food allergy.

Knowing this, it’s easy to see why some of the more noticeable symptoms may be confused with other problems. Sometimes, a dog is reacting to a food sensitivity issue rather than an allergens within their diet. For example, there are several factors that can cause gastrointestinal problems from a dog’s diet, including:

  • Viruses
  • Parasites
  • Bacterial infections
  • Pancreatitis

On top of that, dogs often eat lots of things that they shouldn’t. Also, the symptoms may be diet-related but only caused by a food intolerance; wherein the food has too much fat, improper fiber levels, was prepared improperly, or it contained other ingredients that didn’t agree with your pup’s system. If it seems like your dog is having an allergic reaction, his immune response could simply be derived from food sensitivities. If you cannot detect what your dog is allergic to, it’s highly suggested to go to the veterinarian for further examination.

What are the Symptoms of Food Allergies? 

Although you should be aware of what you’re feeding your pup, and how they’re reacting to that sustenance, diagnosing a food allergy isn’t a simple feat. That said, there are common symptoms that you’ll want to keep an eye out for, including: 

  • Diarrhea 
  • Hot spots
  • Itchiness
  • Lesions 
  • Recurrent ear infections
  • Scabbing
  • Vomiting 

Diagnosing Food Allergies

The most frustrating aspect of food allergies is that they’re difficult to test for. Although there are a variety of tests that are commonly advertised and can be done by a vet (or at home), there’s little to no evidence proving their efficacy. Symptoms of food allergies and food sensitivities often manifest the same. Whether your dog is developing skin allergies, his immune system overreacts to a specific food ingredient, or he’s just not acting like his normal, happy self, it can be incredibly difficult to uncover the source of his issues. In fact, per the Cummings Veterinary Medical Center at Tufts, there’s only one clear way to find out:

The “gold standard” or best method that we currently have, for diagnosing food allergies is the dietary elimination trial. This means feeding your pet a diet purchased through a veterinarian or carefully made at home that contains only a few ingredients (typically one protein and one carbohydrate plus necessary fats, vitamins, and minerals) that your pet has never been fed before or that are hydrolyzed (where the proteins are broken down into very small pieces that can hide from the immune system) or purified to remove the parts that are likely to cause allergies.

With that in mind, the most common foods that cause allergies in dogs are: 

  • Chicken
  • Beef
  • Dairy
  • Egg

Treating Pet Food Allergies  

As their owner, your dog’s health is your number one priority. That’s why when you begin to see your dog’s body has an allergic response, you begin to worry. With that being said, it’s important for you to keep in mind that environmental allergies, pet food allergies, and even stomach issues can often be treated as long as you identify the trigger that’s causing the issues. 

If your dog is displaying symptoms of allergies, in all likelihood it’s the result of a skin or seasonal allergy and not caused by the food they’re eating. So, if you’re concerned, take them to the vet and let them run tests to see what might be ailing your beloved pup! 


  • Merck Vet Manual. Overview of Food Allergy.
  • Web Md. Caring for a Dog with Food Allergies.
  • Modern Dog Magazine. Food Allergies in Dogs.
  • Cummings Veterinary Medical Center at Tufts University. What every pet owner should know about food allergies.


Dr. Melinda J. Mayfield-Davis, DVM, WCHP-AH, brings over 20 years of experience in veterinary medicine.  She is the Technical Services Veterinarian with Innovacyn, Inc., parent company of Vetericyn Animal Wellness. She received her DVM from Oklahoma State University and now resides in Southeast Kansas with her husband, two children, four dogs, and six horses. Prior to working with Innovacyn, Dr. Mayfield owned and operated the Animal Care Center in Columbus, KS.

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