Dog Food Allergy Vs Intolerance

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By Allison Salonko.

Allison is a Veterinary Technician in the state of Indiana. She graduated from International Business College and Vet Tech Institute of Indianapolis with a degree in Animal Science and Technology in 2011.

Concerns regarding food intolerances and allergies in dogs are a hot topic among owners.

Especially with all the booming pet food industry having so much influence over how and what people are feeding their dogs.

Many companies claim that their food omits ingredients that were once common but are now unwanted due to “food allergies.”

The reality is that many people, both the dog food companies and the owners, have no idea what really causes an intolerance or allergic reaction to food. 

This article is here to help you understand what food allergies and intolerances are, what causes them and what the difference between them is.

What are food allergies and intolerances?

There is a big difference between both words.

When one thinks of an allergic reaction to a food you imagine facial or tongue swelling and itchy throat but intolerance is more of a digestion problem with a specific ingredient.

Food Allergy

When someone is allergic to food, especially in people, it can be truly life-threatening.

Anaphylaxis is no joke!

In our canine friends, the symptoms are usually less severe and manifest in different ways than humans.

A food allergy in dogs will cause itchiness localized to the face and mouth.

Hyperactivity and weight loss can also be signs of a food allergy.

Occasionally, there is also some kind of digestive disturbance like vomiting or diarrhea.

Why does my dog have food allergies?

This is a relatively common issue among dogs, so if your pooch is one of them you are certainly not alone in the fight against food allergies.

Our canine friends develop these allergies to food by being exposed to a certain ingredient for long periods of time.

The body starts to form antibodies against a specific food which is what causes the symptoms of the food allergy.

What is my dog reacting to?


Almost every time that a dog is allergic to something in their diet, it is going to be the protein that causes the issue.

Chicken and beef are the first two proteins that veterinarians recommend eliminating when they are suspicious of a food allergy.

It is possible for a dog to react to an ingredient in their diets, such as grain or soy, but it is far more likely that the issue will come from the protein.

On rare occasions, it is something other than protein, and contrary to popular belief it is even less likely that they are sensitive to grain or corn. This trend was an extremely big marketing ploy to popularize holistic and grain-free diets.

How do we diagnose a food allergy in my dog?

Diagnosing a food allergy is not a quick process and it can be frustrating for some owners who have dogs with worse than average symptoms.

Diagnosis requires an elimination diet trial that lasts anywhere from 12 weeks to 6 months.

The diet trial involves feeding your dog a hypoallergenic food, and ONLY that food.

That means, no other treats or snacks.

Not even flavored heartworm or flea prevention can be given during this time.

It is extremely crucial that the variables are limited and well monitored in order to diagnose the correct ingredient.

Do you treat or cure food allergies in dogs?

Treatment only involves feeding your dog the recommended diet and treating any of the side effects of their potential food allergy.

Usually, they need something to counter the itchiness that comes as a symptom of the initial allergic reaction.

Hopefully, as you eliminate suspected ingredients, the need for veterinary visits will decrease.

You cannot cure food allergies.

The only way to handle them is simply to avoid the offending ingredient.

Food Intolerance

A food intolerance is really just a better way to describe any kind of adverse food reaction.

The term covers a broad spectrum of potential issues with food and does not involve the immune system as food allergies do.

What is food intolerance?

There are really only so many ways that the body can demonstrate that it has a problem with a specific food ingredient, so this is why food intolerances are commonly confused with allergies.

A food intolerance usually manifests quickly after eating something, resulting in vomiting, diarrhea and flatulence.

How do I know if it’s intolerance or allergies?

One of the biggest indicators that it is an adverse reaction due to intolerance and not an allergy is if the symptoms occur after the first incident with that food.

Remember, food allergies only develop after long-term exposure to an ingredient.

What would cause a food intolerance?

The reason for dietary intolerance is not entirely known.

Sometimes an issue can be linked to intolerance to carbohydrates or protein, but these are rare.

But the term food intolerance can be used to describe any kind of adverse reaction.

Adverse reactions

These reactions can include ingesting spoiled or toxic foods like old dairy or chocolate, or potentially a plant that causes toxicity and stomach upset.

Then there is the possibility of ingesting a foreign object.

Other adverse reactions to food in dogs

When you are concerned that your dog may have ingested a toxic food or plant or possibly a poison you should immediately call your veterinarian.

Depending on what the food or poison was will dictate how they will handle the situation.

Chocolate and other toxicities

Typically with chocolate toxicity (check out the calculator for it here), the most important factor is timing.

If you manage to catch them right after doing it then you can usually induce vomiting and save yourself the cost of an overnight stay.

If you were a few hours too late to make them puke then the story could be very different.

Especially depending on the type of chocolate and how much they ate compared to their size.

Drugs, medications or poison

Ingestion of one of these items could be potentially deadly if not handled in time.

Typically veterinarians would treat it similarly to chocolate toxicity and induce vomiting.

Foreign object

Foreign body removal surgeries are a pretty common occurrence at veterinary hospitals, big and small.

Dogs are notorious for eating things they shouldn’t, especially articles of clothing, feminine products, toys and bones.

Again, the object in question will dictate how the situation is handled.

Sometimes if you wait it out, nothing bad will come from it, but more often than not some kind of adverse reaction will occur.

Sometimes only a mild bout of pancreatitis is seen and other times the pet will require surgery and an overnight stay to correct the mistake that was made.

Understanding the symptoms to obtain the right diagnosis

Any kind of adverse reaction to food whether it be from an allergy, intolerance of just a dog being a dog and eating trash, the response is usually a messy one.

Be sure to monitor your pet’s symptoms carefully and understand timelines if the symptoms seem to reoccur frequently or never go away.

Jumping to conclusions on your pet’s diagnosis can be a potentially damaging one if you aren’t careful about changing their diet and talking with your veterinarian about their symptoms.


Photo by Mathew Coulton.