Get

In Your Inbox

Dogster is reader-supported. When you buy via links on our site, we may earn an affiliate commission at no cost to you. Learn more.

Food Allergies in Dogs: Our Vet Explains Signs, Causes, Diagnosis & Care

Labrador watching his food

Food allergies are a type of allergy that can affect dogs, causing chronic skin and digestive signs. Some breeds are more prone to food allergies than others, but any dog can be affected. When a dog has a food allergy, their immune system overreacts to a certain food ingredient in their diet, typically a protein, called allergen. The body recognizes this ingredient as a foreign invader, producing antibodies and an immune response to an otherwise normally tolerated food.

Dog food allergies develop over time; the body needs to be exposed to the food ingredient for a long period of time before developing the full reaction. That is why dogs that have eaten the same food for months or years develop an allergy to it and can’t be fed that same diet anymore.

In this article, we’ll explain in a clear way the science behind food allergies so that you can learn more about how to identify, diagnose, and treat this problem, with the ultimate goal of improving the health and well-being of your beloved dog.

divider dog paws 4 oct 2024

Signs of Food Allergies in Dogs

dog scratching
Image Credit: schubbel, Shutterstock

The most common sign of food allergies in dogs is chronic skin problems. Itchiness is very common. However, the itchiness can develop into something worse as the dog continues to scratch. Eventually, the skin will look red, inflamed, and sore. If the dog continues to scratch, secondary infections will set in. Chronic inflammation of the ears (otitis) can also occur.

Dogs may also experience digestive signs, such as soft feces, flatulence (gas buildup), abdominal pain, intermittent diarrhea, blood, or mucus in the stools. Vomiting can occur as well; however, this is rare.

It is important to note that, quite commonly, dogs may suffer from multiple allergies at the same time, such as environmental allergens or flea saliva. This can aggravate the clinical signs and cause occasional flare ups of itchiness (pruritus) in affected dogs.

What Ingredients Are More Likely to Cause Allergies?

Proteins are by far the most common cause of food allergies in dogs. Out of all the proteins, dogs are most likely to be allergic to beef, dairy, chicken, wheat, lamb, and egg. In order to develop an allergy to an ingredient, your dog must have been exposed to it for a period of time. However, you don’t need to avoid these ingredients if your dog isn’t allergic to them. They won’t harm your dog unless their body recognizes them as a foreign substance.

How Are Food Allergies Diagnosed?

Dog check up

Diagnosing food allergies requires a team effort between you and a vet. There isn’t a test the vet can run to determine what exactly your dog is allergic to. Instead, a vet can diagnose food allergies based on your dog’s physical examination, their clinical history, and their response to a food trial.

The instructions for these trials are pretty straightforward and simple. First, your dog should be fed a special diet (called an elimination diet) for 8 to 12 weeks, and no treats or other foods are allowed during this time. The diet chosen should be hypoallergenic for your dog, which means that it contains a protein your dog has never eaten before or it contains proteins that have been hydrolyzed.

The typical proteins used for this purpose are venison, rabbit, or fish. However, finding the right diet can be challenging because there are only so many options on the market, and many companies use similar ingredients. This is why homemade diets can play an important role as an elimination diet. The vet will recommend you to use a single protein and a single carbohydrate source to be fed during the trial. These diets are not suitable for long-term management since they lack important nutrients that your dog needs.

You and the vet may choose to do the food trial using a protein hydrolyzed diet. These are commercial diets in which the proteins have been treated to reduce their size to smaller peptides and amino acids, which can’t be recognized by the dog’s immune system, making it unable to trigger an allergic response to them. These types of elimination diets are suitable to be fed long term if necessary because they are nutritionally balanced and complete.

If your dog’s health problems improve while they are fed the elimination diet and deteriorate once you introduce their old diet back, a food allergy can be diagnosed. This step is called a food challenge. Once you start feeding your dog again the elimination diet and they are free of allergy signs, guided by a vet, you can very gradually start introducing food ingredients (provocation testing) until their skin or digestive system flares up again. This can be the way to diagnose exactly the proteins that cause your dog’s allergies to make your choice for the long-term diet your dog will eat.

If you are concerned about the health and well-being of your pet, seek veterinary advice for the best course of action.

Did you know you can speak to a veterinarian without having to travel? Just head over to PangoVet. It's an online service where you can talk to a vet online and get the advice you need for your pet — all at an affordable price!

PangoVet_Mention-in-Content Savings V1

How Are Food Allergies Treated?

The only way to treat food allergies is to avoid whatever your pet is allergic to or to feed a commercial protein hydrolyzed diet. You can choose a new diet that doesn’t contain whatever food ingredient your pet is allergic to if you successfully found this out. There are many commercial diets available that are made with limited ingredients.

Can Food Allergies Be Cured?

Dog eating happy
Image Credit: alexei_tm, Shutterstock

No. The dog will be allergic to the food ingredient(s) for the rest of their life. However, they can be managed long term with the right diet and avoiding the allergens. Luckily, most pets only require a hydrolyzed protein diet or a diet with limited ingredients. For most dogs that are allergic to a single protein, avoidance is quite easy. The diet they can eat will not contain this ingredient. Of course, for dogs that are allergic to many things, it can be more difficult to avoid the allergens completely.

Dogs with complicated food allergies or with more allergies (for example, environmental allergies) may need medication—either long term just during allergy flare-ups. Of course, this doesn’t cure the allergy, but it minimizes the signs and makes your dog much more comfortable during those times. Allergy management is a team effort that can be very rewarding yet requires close collaboration between you and a veterinarian.

Can a Dog Suddenly Become Allergic to Their Food?

Partially, yes. Your dog may appear as if they have suddenly become allergic to a food they have been eating for months or years but, in fact, this process is gradual. That’s how food allergies in dogs develop. A dog eats the same food for years and, eventually, the overexposure sets off the immune system and allows enough time for antibodies to build up. The dog may exhibit minor signs at first, but these might not be noticeable. Often, pet owners don’t realize that their dog is experiencing food allergies until they notice chronic itching or chronic digestive issues.

If you notice any type of skin irritation, you should consult with your vet. Parasites and allergies are among the most common causes of skin issues in dogs. It doesn’t matter that your dog has been eating the same food for years and has been fine. In fact, that is how food allergies develop in the first place.

divider dog paws 4 oct 2024

Final Thoughts

Allergies can be problematic for any dog. However, once you learn to recognize the signs that your dog has food allergies, you can take action and work alongside a vet to identify and avoid the food ingredient(s) that are causing your dog’s problems. While food allergies cannot be cured, most of the time they can be managed quite successfully with the right diet. If you suspect that your dog might be allergic to something in their food, reach out to your vet. There are many options for feeding your dog to ensure they continue to enjoy an excellent quality of life without skin and digestive problems

See Also:


Featured Image Credit: Olena Yakobchuk, Shutterstock

How useful was this post?

Click on a star to rate (you can leave written feedback after clicking submit)

Help us improve Dogster for pet parents!

Your feedback really matters.

What did you like about this post? Also how can we improve it?

Join the conversation

Leave a Reply

You’re very welcome to leave a comment or question. Please know that all comments must meet our community guidelines, and your email address will NOT be published. Let’s have a positive and constructive conversation.

Talk With A Vet Online

Peace of mind,
anywhere, anytime

Affordable vet advice

7 Norwegian Dog Breeds: Info, Pictures, Origin & History

Cutting into the frigid Arctic Circle, Norway can seem a world unto itself, and one look at the country’s native dog breeds proves...

How Smart Is a Pitbull? Facts & FAQ

Affectionate and friendly when socialized as a puppy, the Pitbull is an amazing dog. Many who own Pitbulls praise them for their devoted...

Why Mental Stimulation Is Crucial for Dogs: 6 Vet-Approved Reasons

We hear a lot about how important it is that dogs get their daily dose of exercise in. Of course, regular physical activity...

English Cocker Spaniel Dog Breed: Info, Pictures, Traits & Care

The English Cocker Spaniel is an extremely friendly dog that doesn’t get too large, so they are adaptable to a wide variety of...

More related

Top 5 Dog-Friendly Beaches in Newport Beach, CA in 2025

California is filled with dog-friendly areas, including the pristine beaches in and around Newport Beach. From family-friendly areas with attractions to wild beaches...

10 Best Dry Dog Foods for Senior Dogs in 2025: Reviews & Top Picks

Owning a senior dog can be a bittersweet time in your life. While you have all these wonderful memories together and a close...

How to Keep Your New Puppy Healthy: 10 Vet-Approved Tips

Bringing home a new puppy is an exciting and fun time for your family but can also be stressful. Puppies can be a...

220 Popular and Unique Cockapoo Names: Ideas for Affectionate and Fluffy Dogs

You’ve just gotten home with your adorable new bundle of Cockapoo fluff. You may have a few awesome names in mind for your...

Keep reading

10 Best Dog Foods for Yeast Infections in 2025 – Reviews & Top Picks

Dogs can suffer from yeast infections similar to humans. Dogs, regardless of their gender, breed, or age can develop a yeast infection at some point due to certain sensitivities, allergies, or a diet high in carbs or sugar. If your...

Labrador dog eating

11 Best Dog Foods for IBD in 2025 – Reviews & Top Picks

As pet parents, we hate it when our pets are in pain or sick. If your dog is suffering from an upset stomach and digestive issues, it could be suffering from IBD or inflammatory bowel disease. If your pup has...

a dachshund dog looks sick lying on its owner

7 Best Dog Foods for West Highland White Terriers in 2025 – Reviews & Top Picks

The West Highland Terrier is a breed of dog beloved by many. If you’re lucky enough to be a pet parent to one of these pups, you know just how quirky they can be. You also know just how important...

West Highland White Terrier dog on green grass

TBHQ in Dog Food: Vet-Approved Feeding & Safety Facts

TBHQ, or tertiary butylhydroquinone, is likely an ingredient that you aren’t familiar with. This chemical additive is commonly used in pet foods to extend shelf life and keep the food from going rancid. You might be surprised to know that...

person pouring dog food to a bowl

Can Dogs Have Food Coloring? Vet-Approved Facts

Food coloring is an ingredient used to make pet food more appealing by visually recreating the look of meats like beef (red), chicken (golden yellow), and vegetables (green), but is it actually safe? The general and basic consensus is that...

Food Coloring pump bottles

How to Cook Chicken & Rice for Dogs: Vet-Approved Bland Diet

For dogs recovering from illness, veterinarians often recommend bland food like homemade chicken and rice 1. It’s an easy-to-digest, low-fat, single-protein diet that is great for gastrointestinal problems. When a dog is sick, this protein and carbohydrate mix can also...

Woman Coocking In A Kitchen Beside a Dog

Can Dogs Eat Blackberries? Vet-Approved Facts & FAQ

As man’s best friend and a curious taster, your dog will likely join you foraging for blackberries in the forest, or welcome you home from the grocery store after buying a carton full of berries with equal gusto. They want...

Can Dogs Eat_blackberries

Can Dogs Eat Pine Nuts? Vet-Verified Nutrition Facts & Considerations

There are many pieces of misinformation floating around the web on what is and is not safe for your canine companions. One of these very topics might have to do with pine nuts. Are pine nuts toxic to dogs? No,...

Dogster-Can-Dogs-Eat-Pine Nuts