Dog Food Allergies: How to Diagnose and Treat?

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Dog Food Allergies

Seeing your dog scratch relentlessly at their skin because of allergies can be sad and frustrating. Unfortunately, there’s no cure for dog food allergies, but it’s possible to diagnose them using an elimination diet. Then, you can treat them by adjusting their diet and using the medication as needed.

Commercial dog foods often have a lot of fillers and additives that can lead to itching, sneezing, gastrointestinal upset, and rashes. This is mainly because of a brand’s desire to produce more and charge less. In other words, quality takes a backseat to quantity.

Dogs can develop allergies to almost anything, but the most common allergens you’ll find are proteins. This includes meats, eggs, and gluten, an essential protein in wheat and soy. The bad news is that these are all the most common ingredients in dog food.

Considering almost everything you find in dog food could be an allergen, the idea of finding the culprit might be overwhelming. So, how do you go about figuring out the issue? More importantly, how do you fix it?

First, don’t get overwhelmed. Allergies are frustrating but treatable. So, in this guide, we’ll help you do the following:

  • Spot the signs of a food allergy
  • Identify the allergy 
  • Treat the allergy
  • Create a hypoallergenic diet

What Are Dog Food Allergies?

Food allergies work much the same for dogs as they do for humans. A dog with an allergy ingests an allergen, then their immune system works to remove the allergen from their body. Since that’s much easier said than done, your dog might develop hives, have trouble breathing, or show signs of GI distress.   

Food allergies affect a relatively small percentage of dogs. According to the BioMed Central Veterinary Research, only 1 to 2% of household dogs are allergic to food. However, food allergies make up approximately 10% of all dog allergies. 

Can Any Type of Dog Have Allergies?

Yes, any dog can fall victim to allergies, including ones to food. So, when you’re looking for a new dog, there won’t be a specific breed to gravitate to or avoid. 

Studies show a handful of breeds with a genetic predisposition to either being born with or developing allergies. These breeds include:

  • Cocker Spaniels
  • Labrador Retrievers
  • West Highland White Terriers

Another thing to consider is that dogs can either be born with allergies or develop them over time. Certain breeds are more prone than others to be born with an allergy, but any breed can develop one as they grow. 

What Are the Signs of a Dog Food Allergy? 

There are different allergy symptoms.

If you’ve ever had an allergic reaction to a food or environmental allergen, you’re already familiar with the signs of an allergy in dogs. Some of the most common symptoms and allergic reactions include the following:

  • Hives
  • Rashes
  • Itching (itchy skin)
  • Licking
  • Chewing
  • Sneezing
  • Breathing difficulty
  • Vomiting
  • Diarrhea
  • Lethargy
  • Weight loss

Another sign of a food allergy is aggression, although this isn’t specifically due to the allergen itself. Often, when a dog is injured or sick, they’ll become aggressive. This is generally a way of protecting themselves from further harm.  

What Are Common Food Allergy Triggers?

Dog Food Allergies Infographic

Commercial dog foods tend to have a long list of ingredients. Some are easy to identify, while others may leave you scratching your head. This can make narrowing down allergy triggers a bit tricky. 

If you start to see the signs of a food allergy in your dog, take a look at the ingredients in their dog food. If any of the following things are in your dog’s food, you should consider them potential allergens.

Most typical dog food allergens [1]:

  • Beef
  • Diary products
  • Chicken
  • Wheat
  • Soy
  • Lamb
  • Corn
  • Eggs
  • Pork
  • Fish
  • Rise

You’ll notice that these ingredients are either protein-rich, act as a filler, or as an additive. Fortunately, there are plenty of dog foods to choose from that don’t include ingredients on this list. 

How to Diagnose Food Allergies in Dogs

If you want to improve your pet health, you should know how to diagnose allergies and what are the options for a treatment.

Frustratingly for pet parents (not to mention the dog), blood or skin tests aren’t reliable options for diagnosing a dog’s food allergy. Instead, the best way to determine what’s upsetting your dog is to use an elimination diet.

The first thing you’ll need to do is confirm your dog’s allergy is to food and not some other allergen. Since dogs can suffer from environmental or airborne allergens, such as fleas or pollen, you should rule those out before diagnosing a food allergy.

What’s an Elimination Diet?

An elimination diet is a step-by-step approach to diagnosing an allergy. It involves eliminating foods from a diet one at a time until you can identify the offending allergen. The process can be quick or take several months, depending on how long it takes to find the food.

Although you can try an elimination diet on your own, your best bet is to work with a veterinary nutritionist. These doctors have the expertise to help you diagnose and treat your pup with minimal aggravation.

When you start an elimination diet, you’ll remove everything your dog currently ingests from their diet and replace it with novel protein (ingredient). It’s essential that you stop feeding your dog anything they were getting before, including food, treats, and table scraps. You’ll also need to make sure your dog stays away from garbage or things outside they might like to chew on. 

Elimination diets take time and patience, so don’t give up if you don’t see immediate results. Even if your dog shows minor improvement, you’ll need to stick to the diet for a few months before determining success. 

How Can You Treat a Dog’s Food Allergy?

There are a few different ways you can treat your dog’s food allergy.


If your dog has an allergic reaction, you can treat it medically just as you would a human. Antihistamines, such as Benadryl or nasal sprays, can help ease the symptoms of a reaction. However, these are good for attacks but not for treating allergies long-term.

Strict Diet

In a perfect world, you’ll test out an elimination diet, find the culprit, and cut it from your dog’s diet. When that happens, adhering to a strict diet that excludes the allergen will likely solve your problems. 

Hydrolyzed Protein Diet

If your dog is allergic to specific proteins, your vet might recommend a hydrolyzed protein diet. The proteins in these foods are broken down to prevent your dog’s immune system from recognizing them. 

Long Term Effects Due to Untreated Food Allergies

Untreated allergies can lead to long-term adverse effects for your dog. These can include:

  • Ear problems
  • Skin infections
  • Yeast infections
  • Eye problems
  • Upper respiratory distress

Treating allergy attacks as they happen can alleviate the symptoms initially. Still, repeated infections over time will make your pup’s immune system work overtime. This could ultimately make it harder for them to fight off other illnesses or viruses. 

Top 10 Signs Your Dog May Have Food Allergies 

Here’s a more detailed breakdown of the most common signs your dog might suffer from a food allergy. 

Chronic Ear Infections

Chronic Ear Infections are one of the main symptoms of food allergies. Signs of an ear infection are frequent head shaking, discharge, and inflammation. If you notice any of these things, you should speak with your vet. 

Gastrointestinal Problems 

There are a lot of reasons why dogs might develop GI problems. Eating grass and digging through the trash are common reasons, but food allergies or sensitivities are also likely culprits. 

Hair Loss 

Hair loss is one of the side effects due to a skin infection. Dogs that scratch and lick obsessively at skin irritants can eventually develop bald spots. These areas will show clear signs of infection or irritation.

Hot Spots

“Hot spots” in terms of allergies refer to spots on your dog’s skin that feel hot and moist. They’re typically the result of excessive scratching, licking, or chewing. You’ll find them in the areas your dog licks and scratches most often. 

Skin Infections

Skin infections are another common sign of an allergy. These can appear as raised, hot patches, sores, and red splotches. You might also notice bald spots around the infected area, especially if your dog has longer hair or licks a lot. 

Discolored Nail Beds

Discolored nail beds are a subtle but tell-tale sign of allergy-induced infection in dogs. If your dog is allergic to their food, the immune response may trigger their nail beds to turn red, brown, or bronze. However, this might not be immediately evident in dogs with darker nail beds. 

Watery Eyes

Watery eyes are the universal sign of an allergic reaction. The wateriness can cause a glue-like discharge in your dog’s eyes. If you leave it untreated or the allergic reaction is bad enough, your dog might even struggle to keep their eyes open.


Swelling, especially around the ears, lips, and eyes, is another common symptom of an allergic reaction. It’s also one of the most obvious since swelling can’t be as easily concealed by fur as rashes or other skin issues.


Hives are another typical sign of an allergy. Although they can show up as much as 24 hours after ingesting an allergen, hives usually appear on the skin within an hour or two after eating. You might not be able to see them under your dog’s fur, but itching and chewing are clear indicators.

Food Intolerance in Dogs: Similarities and Differences From Food Allergies

It can be easy to confuse food allergies and food intolerances. After all, both often share similar symptoms, including GI problems and skin irritation. The key difference is that an allergy involves an immune response, while an intolerance doesn’t.

Another difference is the onset of the reaction. In many cases, an allergy will develop slowly over time. On the other hand, intolerance or sensitivity usually presents itself after the first contact with a specific food.

You should treat food intolerances just as you would an allergy by avoiding the irritant in the future. Of course, dogs often get into things they shouldn’t. So, if the reaction occurred after your pup went trash can diving or digging in the backyard, take steps to prevent the behavior in the future. 

Choosing the Right Food for Your Dog

Many new dog owners will pick the most popular or least expensive dog food for their new pets. In most cases, that’s fine. Although those foods might not be the healthiest, they’re unlikely to hurt your dog. 

However, if you own a breed predisposed to allergies or notice mild signs of an allergy, you can try a few options to ease your dog’s symptoms.

Prescription Dog Food

If you know your dog has a specific allergy, your vet might recommend a prescription diet, such as the hydrolyzed diet mentioned above. Although this can get pricey, this is often the best way to keep your dog healthy and itch-free. 

Grain-Free Diet

Corn, wheat, and other grains are common allergy offenders for dogs. These are often used as fillers in many commercial dog foods, so extra caution should be taken when buying foods with these ingredients. To lessen the likelihood of a reaction, you can eliminate any foods that contain grains. 

Food With Minimal Ingredients

As with most foods, the fewer the ingredients, the better. Focus on foods that have simple, easy-to-pronounce ingredients. Not only are these foods healthier, but it’ll be easier to find an allergen if your dog has a reaction. 

Avoid Major Allergens

Take another look at the allergens listed above. Then, when shopping for food, choose those that don’t contain any of the most likely offenders. For example, select lamb or rabbit over chicken or beef, and avoid dairy, chocolate and eggs.

You can read our list of foods your dog should avoid.

Choose Novel Ingredients

Novel ingredients are those you’re less likely to come across in standard commercial dog food. Things like fish, duck and sweet potatoes are excellent sources of protein and carbs that are less likely to irritate your dog.

Dog Food allergies – Final Thoughts:

So, how do you diagnose and treat dog food allergies? The easiest way to diagnose an allergy is to try an elimination diet. It’ll take time, but once you narrow down what your dog should avoid, you’ll have no problem keeping them healthy. 

If you think your dog has an allergy and you want to start an elimination diet, reach out to your vet. They’ll be able to guide you on the path to getting your dog back to their happy, playful self once again.

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Sal is the founder and editor of Dog Food Point and an avid dog lover who is passionate everything related to dogs. With over 20 years of experience as a passionate dog lover and expert in dog nutrition, Sal is committed to sharing valuable information and advice to promote happy, healthy dogs. When he is not playing with his pooch Tara, Sal spends most of his time reading, writing, and cooking for his dogs.

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