What to Do If Your Dog Is Allergic to Food

Having a dog with allergies can be incredibly frustrating for a dog owner, especially since the cause of the allergic reaction can often be very difficult to properly diagnose.

But if you notice common dog allergy symptoms such as constant itching and scratching on top of a poor coat quality and chronic canine ear infections, it may point to a food allergy. Having a dog allergic to food means you have to be extra cautious with what you feed him. Sometimes, the food you are feeding him can be causing these uncomfortable side effects. While this doesn’t make you the bad guy, it does mean you should pay close attention and switch your dog’s food if you suspect that allergies to his current diet may be the cause.

When Do Food Allergies Occur

So how is your dog allergic to dog food anyway? A food allergy in dogs is an over-response in your pup’s immune system to an invading protein. When your dog has a food allergy, he is allergic to the specific protein found in certain and sometimes many foods.

Normally, when your dog eats a meal, he digests the food in the stomach. Large pieces of food are broken down in the stomach and then move into the small intestine where it is further digested until the proteins are broken down into amino acids. These amino acids are then absorbed into the dog’s body. When a dog has an allergy to a protein, it is absorbed in the intestines instead of first being broken down. The dog’s immune system will then react, which is when your dog shows signs of a food allergy.

What are the Common Signs & Symptoms of Food Allergies in Dogs?

The signs and symptoms of food allergies in dogs can vary widely from dog to dog, but most often can be identified first by non-seasonal itching. This itching is often focused on the dog’s ears and feet, however, this does not necessarily indicate a food allergy and can still be triggered by another allergy or health condition.

The symptoms of a food allergy in dogs may seem to appear out of nowhere. These symptoms may include:

If your dog exhibits any of these symptoms, you should bring him in to see your veterinarian as soon as possible to determine if these symptoms are because of a food allergy. If your dog does indeed have a food allergy, continuing to feed him the food can cause further harm, and even be life-threatening if he continues to eat this problem food. That’s because the more a dog is exposed to the protein he is allergic to, the more severe the reaction he will have.

What Causes Food Allergies in Dogs?

Dog allergies are most often triggered by proteins found in foods. These proteins can be found in both animal or plant-based foods that are common to dog diets. When a dog has an allergy, these proteins are misidentified as a threat by the dog’s body. The development of an allergy will take some time, meaning the dog may eat the problem food for quite a while before any symptoms become noticeable.

Identifying your dog’s problem foods can be a difficult endeavor, especially since a dog can be allergic to pretty much any food ingredient. However, there are certain foods that are known to be more likely to cause an allergic reaction than others. These more common problem foods include:

When a dog is allergic to one ingredient, it is likely that he is allergic to other proteins as well. To find out which foods are the problem, your veterinarian will likely have to put your dog on an elimination diet, which will be followed by a food challenge. During this elimination diet, you will feed your dog only one or two foods at a time, and see whether or not your dog has a reaction to the foods.

You will gradually add more items and ingredients until your dog has an allergic reaction. In this way, you will identify which foods your dog is allergic to and then be able to eliminate them from your dog’s diet.

Sometimes, your dog will have an allergic reaction no matter what combination of food you give. In these cases, your dog is likely allergic to something else in the environment, such as pollen, a specific fabric, dander, or even a medication.

While having a dog with a food allergy can be frustrating, there are much more food options available than there were just a few years ago. Once you identify the problem food or foods, you can remove them from your dog’s diet and start him on new foods that will keep him healthy and happy. However, make sure you have made a proper diagnosis in order to get there.

How are Food Allergies in Dogs Diagnosed?

The only way to reliably diagnose a food allergy in your dog is through a food trial using a hypoallergenic dog food. You can do this by using a novel protein source or a hydrolyzed protein.

Novel protein sources are those that will be completely new to the dog, which has a lower chance of triggering an immune response. Since plants also contain protein, this diet should also contain a single, novel source of carbohydrates. These hypoallergenic dog foods may include combinations like venison and potato, salmon and potato, duck and pea, or even a protein like kangaroo. One note here: lamb is in so many dog foods that it is no longer considered to be a novel protein.

A hydrolyzed diet is made when these animal proteins are not recognized in the body as allergens. A starch, such as potatoes, or rice will typically be used as the carbohydrate since they are very infrequently associated with an allergic reaction.

During this testing period, the food combo should be given to your dog for a minimum of eight to 10 weeks. This gives proper time to adequately test your dog’s response since allergic reactions take time to develop. You should notice an improvement within the first four to six weeks after the new diet as begun, but some breeds, such as Labrador Retrievers or Cocker Spaniels, have been known to take a longer time to respond to the new diet.

During the testing period, it is imperative that you only feed your dog the new hypoallergenic diet and avoid all other foods, including treats and flavored medications.

After you have identified the food allergy using the hypoallergenic diet, you should conduct a second challenge to confirm the diagnosis. Going back to the dog’s original diet should make symptoms reoccur within a couple of weeks. When the food allergy is confirmed, you can add in single ingredients to the hypoallergenic diet to see what exact food or foods is causing the reaction and avoid this ingredient moving forward.  

What Should I Feed My Dog if he has a Food Allergy?

As we mentioned above, the best diet you can give your dog if you suspect a food allergy is present is a canine hypoallergenic diet. You will use novel protein and hydrolyzed foods, possibly prescribed by your veterinarian, to improve your dog’s systems as these foods do not often trigger allergic reactions. You should not randomly eliminate ingredients from your dog’s normal diet because you may cause nutritional imbalances that will not help you to identify the problem food. Always seek the help of a veterinary nutritionist.

How to Prevent Food Allergies in Dogs

Finding the source of a food allergy is difficult enough, but trying to prevent food allergies is another challenge entirely. And while you simply cannot completely prevent a food allergy from happening, there are steps you can take to help stop several common allergies.

First, you can start when your dog is just a puppy. Make sure to feed him a healthy diet and give them adequate nutrition so they can build a healthy mucosal barrier, which can help prevent food allergies in the future.

While your dog is still a puppy, you can also try to prevent canine gastroenteritis, which is believed to result in a dog that is more susceptible to developing food allergies. The theory of preventing this occurrence is to only feed your pet dog food and dog treats and nothing else. This is trickier than it sounds, as dogs tend to eat anything they can get a hold of.

It takes a lot of patience and a careful eye to monitor what your dog consumes at all times. While many of the items he can consume in the environment are harmless, some may trigger allergic reactions. These environmental triggers will be much more difficult to identify than a food allergy since you generally know what you are feeding your dog.

If you suspect an allergic reaction is due to something your dog got into rather than his normal diet, you should try a low-protein meal plan until your dog’s upset stomach or diarrhea goes away. If either lasts for more than 72 hours, take your dog in to see your veterinarian.

You can also promote effective protein digestion in your dog at a young age. When you feed your dog a homemade diet, considering blending up the protein into smaller pieces, which will help with digestion. Regular dog food is already processed, so you will not need to blend it further.

It’s also a good idea to keep things simple when it comes to your dog’s food. Choose a brand that has only one or two protein sources so you will have options to switch should your dog develop an allergy to its food. Starting your dog on a food with fewer ingredients will make it easier for you to find foods without the problem ingredient later on.

While prevention is not a foolproof plan, especially in breeds that are more prone to developing food allergies. In these instances, sometimes there is a  genetic component to food allergies, meaning there is really nothing you can do to prevent them from occurring.


Dealing with a dog that has a food allergy can be a real challenge for any dog owner, but it is best to stay positive, as being negative and frustrated with your dog will only stress the animal out and make it more difficult on the dog. If you suspect your dog has a food allergy, use an elimination diet to find the problem food and then systematically remove the food from your dog’s diet. Finding a safe meal plan for your dog will allow both of you to resume your happy and healthy lives together.


“Food Allergies in Dogs.” Modern Dog Magazine, Accessed 5 Dec 2018. www.moderndogmagazine.com/articles/food-allergies-dogs/15131.

Eckstein, Sandy. “Caring for a Dog with Food Allergies.” WebMD, Accessed 5 Dec 2018. www.pets.webmd.com/dogs/guide/caring-for-a-dog-that-has-food-allergies.

“5 Signs Your Dog Has Food Allergies.” Dogs Naturally Magazine, 26 Nov. 2018, Accessed 5 Dec 2018. www.dogsnaturallymagazine.com/5-signs-your-dog-has-food-allergies/.

“The Best Food Options for Your Dog with Allergies.” PetMD, Accessed 5 Dec 2018. www.petmd.com/dog/centers/nutrition/evr_dg_best-dog-food-for-dogs-with-food-allergies.

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