Dog Food Allergies: Symptoms, Causes & Treatment

Dog allergies are rare but if untreated they can lower the quality of your pup's life. Learn how to diagnose and treat food allergies in dogs.
dog licking paw

Everyone knows someone allergic to strawberries or peanut butter. But dogs can suffer from food allergies too.

Allergies can cause severe itchiness and gastrointestinal discomfort for dogs. And an elimination diet is critical for determining if food is the culprit.

I met lots of concerned owners who believed their pets were allergic to food when I worked in a vet hospital.

Although rare, dog food allergies or intolerance can lower your pup’s quality of life. Keep reading to learn more about how to diagnose and treat this troublesome problem.

What Are Food Allergies

Food allergies happen when your dog’s immune system attacks protein from his food. [1] The resulting immune response can cause severe discomfort and even infections.

A variety of allergens can cause this response in dogs.

Skin allergies, environmental allergies, and food allergies can all affect our furry friends. [2]

Unfortunately, the symptoms of these issues often overlap. It can be difficult for owners to determine the cause of their dog’s problems.

Food allergies can cause gastrointestinal disturbances like vomiting and diarrhea. But the primary symptoms of this condition resemble environmental irritations.

Yet, dogs with gastrointestinal symptoms often have food intolerances, not allergies.

Food Intolerance

Dog food intolerances cause similar symptoms to food allergies. But they do not involve an immune response.

These adverse reactions are often confused for allergies because they trigger identical reactions.

One distinguishing characteristic of food intolerances is their impact from an initial exposure. Reactions by the immune system need several experiences with the allergen before causing symptoms. [3]

An allergic reaction is a hypersensitivity reaction. The immune system develops antibodies for the protein after the initial exposure. When those antibodies reencounter the allergen, they trigger an immunologic response.

True food allergies are rare. Only 1 to 2 percent of dogs suffer from food allergies or intolerances. [4]

Dogs suffer from many of the same intolerances as humans. Although I enjoy my fair share of ice cream, I have several lactose intolerant friends.

Lactose intolerance is a common carbohydrate food intolerance in dogs. Affected dogs may suffer from diarrhea and bloating if they eat dog food that contains dairy. [3]

Yet, dairy is not the most common dog food allergy.

Common Food Allergens

Dairy, meat, and eggs are all considered common allergens.

The food item itself does not cause an allergic reaction. Your dog’s immune system is responding to a specific protein found in those foods.

Although animal products do sometimes cause allergies, plant products also contain protein. Your pet can develop an allergy to vegetables, fruits, and grains too.

Research studies determined beef was the leading food allergen for dogs. Other common culprits include dairy products, chicken, wheat, and soy. [5]

Top dog food allergens according to a 2016 Clinical Study:

common food allergens dogs
Common food allergens in dogs

Keep in mind, the percentages above come from dogs already experiencing adverse food reactions. These items are safe dog food ingredients for most dogs.

Symptoms of Food Allergies and Long Term Effects

dog allergies symptoms
Dog allergies symptoms

Symptoms of food allergies in dogs resemble skin allergies. It is difficult to determine if your dog is allergic to food or environmental allergens.

The immune response triggered by allergen protein from food can vary in symptoms. Common symptoms include skin conditions, gastrointestinal disruption, or a combination of both. [6]

Sometimes, a severe reaction can cause anaphylaxis. This reaction releases a flood of chemicals that cause shock.

Anaphylaxis is a severe condition that requires veterinary help. Some people with severe peanut allergies may experience this reaction.

Food allergies can also cause hives, facial swelling, or ear infections. Vomiting and diarrhea may indicate either a food intolerance or an allergy.

Common Dog Food Allergy Symptoms

  • Itching
  • Ear infections
  • Sneezing
  • Hot spots
  • Scaly or oily skin
  • Skin rashes
  • Secondary bacterial infections
  • Discolored skin
  • Strange skin texture
  • Red eyes and discharge
  • Hair loss

Long Term Effects of Dog Food Allergies

Food allergies may seem like a minor inconvenience. But, untreated symptoms can develop into severe health conditions.

Untreated allergies can even promote the development of more allergies.

Secondary skin infections can result from itching. The prolonged discomfort can also cause behavioral changes.

Although allergies rarely kill animals, bothersome symptoms can reduce their quality of life. And constant itching can feel like torture if left untreated.

When your dog feels bad, his behavior can change for the worst.

Understanding food allergies is essential for avoiding chronic problems and promoting good health. Troublesome dog food allergies need a swift diagnosis and effective treatment.

How To Diagnose Food Allergies In Dogs

Diagnosing allergies is a complicated process. If you have undergone testing yourself, you appreciate the difficult diagnosis.

But identifying the cause of your dog’s allergies is critical for his quality of life. If you do not find an accurate diagnosis, complications can arise.

Once you know what your dog is allergic to, it is easy to prevent future reactions.

Allergy testing and elimination diet are two common ways to diagnose a dog food allergy. But before you begin testing, your vet will want to rule out other possible conditions.

Chances are your dog’s symptoms aren’t caused by a food allergy at all. And incessant itching most likely results from environmental reactions.

I struggled with my dog’s itchy skin in the past. I worried about a food allergy. 

But my veterinarian discovered she had flea allergy dermatitis. Some dogs have this reaction because they are allergic to flea saliva.

In veterinary clinics, we only find food allergies in about 10% of dogs who come in with the concern. [7] Your veterinarian may examine other issues before recommending food allergy testing.

Elimination Diet

The best way to diagnose a food allergy is with a diet trial. The trial consists of using an elimination diet to test the effect of certain food items.

Distinguishing between allergies and intolerance is difficult if food is the issue. But, at least you know the source of the problem.

Before beginning the trial, you need to get a complete diet history. Owners concerned about food allergies should know every single ingredient their dogs eat.

When your dog is struggling, studying his diet is especially important.

You should work with a veterinary nutritionist to review your dog’s diet history. They can also help choose an appropriate diet never before exposed to the pet.

The elimination diet strategy involves feeding your dog a new and pure diet for several weeks. [8] The diet should continue to provide appropriate, balanced nutrition.

During the trial, refrain from feeding any extra treats or supplements.

I know I am a total sucker for sneaking my dog extra snacks! How can you resist a cute fluffy face?

But for accurate results, you must avoid contamination.

For example, consider a dog who has been on a chicken and rice diet. You may put him on a diet of fish and potatoes.

You can also use a diet of hydrolyzed proteins that enzymes have broken into smaller pieces. Proteins usually elicit an allergic reaction. So, the dog’s immune system may not recognize the elements.

If your dog’s issues disappear during the trial, his problem is likely food-based.

To prove that he has a food allergy, you must feed him the suspected food after the trial. A reaction at this point would mean a good chance of a food allergy.

Allergy Testing

Allergy testing is another form of allergy diagnosis humans may recognize. If you have allergies, you may remember patch tests on your back or arms.

Veterinarians can also perform a blood test or patch test on your dog.

Blood tests use blood samples to test for allergic reactions to food. Unfortunately, they are not very accurate. Elimination diets can provide much more insight on the subject.

Patch tests are another form of allergy testing. They are uncommon in dogs but more accurate than blood tests. [9]

During a patch test, a specific protein mixes with vaseline. Doctors tape the mixture to the skin and test after two days of exposure. Skin irritation indicates a positive test and a potential allergy.

If you are trying to diagnose a food allergy in your dog, try an elimination diet first. This method is the best way to find potential allergens in your dog’s diet. You can always complete tests later for more information.

Predisposition to Dog Food Allergies

Concerned pet parents may worry about their dog’s predisposition to food allergies. If a parent has an allergy, there is some evidence that their offspring can inherit it.

Genes can play a role in the development of food allergies. But little evidence suggests that individual dogs are more at risk than others.

When do food allergies usually appear?

Some vets have reported allergies emerging in puppies under one year old. But the vast majority of allergies develop after the first year of life.

The immune response responsible for allergic reactions requires previous exposure. So, allergies do not usually occur at a very young age. The dog has not had significant exposure to much at that point.

Food allergies can also emerge later in a dog’s life, like humans.

I never had allergies as a child. But now my allergies always remind me when spring is around the corner!

Can food allergies occur after years of the same diet?

It is common for dogs with food allergies to develop an allergy to their current diet. Even diets your dog has eaten for years with no problems.

Dogs have to become sensitized to a protein to develop an allergy. They cannot react to something the first time they eat it. If they do, it is an intolerance, not an allergy.

Continual exposure to a particular food item allows the development of antibodies. Your dog’s immune system can then attack that allergen if it identifies the food as a threat. [10]

Your pup may not be allergic to his current diet now. But he could develop allergies in the future.

And when you find a diet that works for him, you may need to change it in the future. Avoiding allergens is an ongoing process throughout your dog’s life.

Are certain breeds prone to food allergies?

Any kind of dog can develop food allergies. There is little evidence to confirm that certain breeds are more at risk.

Some veterinarians do believe food allergies are more common in particular breeds. Examples of these breeds include Labrador Retrievers, West Highland Terriers, and Cocker Spaniels. [11]

Dogs are very adaptable to a variety of diets. So, certain breeds do not have predispositions for specific types of food allergies.

The dog’s age or sex also appears to have no impact on the development of food allergies. Both male and female dogs can experience allergic reactions at any age.

How to Treat Dog Food Allergies

Dog food allergies are tricky to diagnose. But treatment is simple if you identify the root of your dog’s problem.

Food allergy treatment depends on a single principle: avoidance.

Once you identify the foods that your dog is allergic to, make every effort to remove those items from his diet.

The elimination diet is essential because it identifies the foods your dog tolerates. The diet change will also treat your pup’s condition if he has a food intolerance instead.

Feeding your dog a different diet is effective at treating an allergy. Your dog’s immune system can not react to a protein that he does not consume.

Working with your veterinarian to develop the right diet for your dog will help a lot.

For severe allergies, medications can also provide relief.

Antihistamines and Medication

If you suffer from allergies yourself, you may use Benadryl to help control your symptoms.

Benadryl and other antihistamines are generally safe for veterinary use. They help soothe itchy skin and relieve annoying symptoms of allergies. But, they do not treat the root cause.

These medications block the effects of histamine. Histamine releases from the immune system when it detects an invader.

Allergies cause your dog’s body to attack food as an invader. The histamines released contribute to this allergic reaction. [12]

Medication can help manage allergies. But always follow your veterinarian’s recommendations when considering this treatment.

Can you cure dog food allergies?

Unfortunately, there is no cure for dog food allergies. Allergies of any kind persist for a lifetime.

But, you can manage the symptoms caused by the allergy. If you can identify what your dog is allergic to, you can avoid it.

By avoiding allergens, dogs can live a happy and healthy life. Your vet may also prescribe medications to help manage allergies when you can’t limit exposure to the allergen.

Taking action is critical. If you believe your dog is suffering from dog food allergies, talk to your veterinarian today.

Allergies last for a lifetime and can limit your pet’s quality of life. But eliminating culprit foods is a simple and effective solution.

The Bottom Line

Dog food allergies are rare in dogs.

Often, the source of your dog’s gastrointestinal discomfort is food intolerance, not allergies. But using an elimination diet to identify the problem food item is vital for both conditions.

I know it might be hard to say no to a cute wet nose looking for a snack… but your dog’s health is worth it.

Besides avoiding specific allergens, be sure never to feed your dog these dangerous foods.