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.

How to Diagnose Food Allergies in Dogs: Signs to Look For (Vet Answer)

golden-retriever-not-eating-its-food_

With the rise of “boutique” pet foods and smart marketing, dog food allergies are a hot topic. While marketing experts have made the public believe that grains, “fillers,” and processed foods are all the culprits, the reality is that most food allergies we see in dogs can be attributed to the protein source. In addition, it’s important to remember that any dog can be allergic to anything, including food, environmental sources, contact sources, fleas, etc.

Diagnosing the source of dog allergies can be difficult, especially when it comes to food. In this article, we’ll discuss the three main ways that food allergies in dogs can be diagnosed and what types of diet options there are if your dog has food allergies.

dogster face divider

The 3 Ways to Diagnose Food Allergies in Dogs

1. Elimination Food Trial

woman and labrador dog consulting with the vet
Image Credit: SeventyFour, Shutterstock

Dogs are going to most commonly be allergic to the protein source in their food. This includes chicken, beef, lamb, salmon, white fish, venison, eggs, etc. An elimination food trial is easy in theory to complete but can be very difficult for some households to adhere to. Here’s a step-by-step guide on what to do. As always, an elimination diet for dogs should be discussed, and details should be ironed out with a veterinarian first.

Steps to take:
  • Write down the brand, flavor, and ingredients of any dog food, treat, or human food your pup has ever received. Pay close attention to the protein sources and common ingredients.
  • Once your list has been made, you need to then put your dog onto either a novel protein diet or a hydrolyzed diet. The diet either needs to contain a protein source and ingredients that your dog has never been exposed to before (novel protein) or be a diet that is formulated to reduce allergic reactions (hydrolyzed diet). Which option to choose should be discussed with a veterinarian.
  • Your dog should be weaned onto the new diet over a 1–2-week period. Every day, mix in more of the new diet and less of the old. A slow wean helps to decrease any GI upset.
  • In addition to the new food, your dog also needs to be put on the same novel protein treats or hydrolyzed treats. Absolutely no outside food, treats, or handouts should be given. This includes their regular preventatives as well.
  • Pending that your dog does not suffer any GI upset, the new diet should be strictly adhered to for at least 2–4 months (depending on a veterinarian’s recommendations). It’s important not to flip flop food if “nothing works” in a week or two as this will just cause your dog’s immune system and GI system more havoc.
  • Speak with a veterinarian about re-introducing certain ingredients one at a time after 2–4 months. If your dog did great on the food trial (had a decrease in allergy signs) but then has a recurrence of signs once one or more ingredients are re-introduced, then your dog is likely allergic to that ingredient.
  • Discuss what types of foods to feed or not feed your dog long-term, pending the trial results with a veterinarian.

2. Blood Testing

There are blood tests that can be performed to test for specific food allergies. These tests have to be submitted to one of only a few laboratories that run them. Because of this you may not have results for a few weeks, and it can be expensive, depending on where the veterinarian has to ship the blood samples.

There are also blood tests for environmental allergies as well. Though typically, there are separate panels for food and environmental factors.

Many veterinarians, especially Board Certified Veterinary Dermatologists, do not like the blood tests as much as other diagnostic options. However, if your dog lives in a household where a strict elimination diet trial is not possible, or they have a housemate that they share food and treats with, then blood testing may be a good option.


3. Skin Testing

Nurse helping vet examining stomach of labrador retriever dog
Image Credit: Dragon Images, Shutterstock

Another option for diagnosing food allergies would be to see a Board Certified Veterinary Dermatologist and speak to them about skin testing. This is a test similar to what is done in people. However, many veterinarians do not believe this is an effective way to rule in/out certain food allergies. The dermatologist will best be able to discuss all diagnostic options, cost, and what is best for your dog.

dogster paw divider

Food Options for Dogs with Allergies

Once a food allergy or allergies have been diagnosed, there are many good options to feed your dog nowadays. One type of food, as mentioned above, is the hydrolyzed protein diet. These are prescription diets whose protein source has been broken down into smaller molecules typically too small to be recognized by the immune system.

Another diet option, briefly discussed above, is a novel protein. This is a type of protein source that your dog has never been exposed to before. Typical novel protein sources include venison, kangaroo, rabbit, and salmon. These types of foods are also prescription as many OTC foods that claim to be “limited ingredient” sneak in multiple types of proteins. This is because many marketing schemes have convinced the public that grains, corn, and by-products are the enemies. Therefore, many OTC foods will still contain multiple types of proteins but claim to be good for allergies because they don’t include grains. Don’t fall for this! Always speak with a veterinarian about their recommendations, but most of us are going to recommend a single-protein diet with grains.

If you need to speak with a vet but can't get to one, head over to PangoVet. It's an online service where you can talk to a vet online and get the personalized advice you need for your pet — all at an affordable price!

PangoVet_Mention-in-Content Savings V1

You can also home-cook your dog’s novel protein diet. This needs to be nutritionally balanced, and the veterinarian will likely recommend working with a veterinary nutritionist if you wish to cook your dog’s food at home. This can be extremely time-consuming, and for some families, especially with big dogs, it’s out of their budget to do this. However, the option is there as long as strict nutrition guidelines are followed.

English cocker spaniel dog eating in the kitchen
Image Credit: Switlana Sonyashna, Shutterstock

dogster face divider

Conclusion

Any dog can be allergic to any type of food and anything in the environment. There are a few diagnostic options for determining what your dog may be allergic to as far as their food. However, the best and most recommended option is the elimination diet trial. You should work with a veterinarian to determine what type of food your dog should be fed during this trial and how long to complete it.

It’s important to remember that this needs to be very strict – every member of the house needs to comply, or it will be a complete waste of time. If and when you and your veterinarian have determined what ingredient(s) your dog may be allergic to, then you can discuss what your dog should be eating long-term. Many people choose to put their dog on a prescription diet long-term as it is the easiest and least time-consuming. However, you can choose to home-cook your dog’s new diet as long as you are working with a veterinary nutritionist.


Featured Image Credit: Phuttharak, Shutterstock

Want content like this delivered to you?

Sign Up For Our Newsletter

News, insights, expert advice, and everything dog

* By submitting, you agree to our Terms & Conditions and Privacy & Cookies Policy.

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

Golden Mountain Doodle Dog Breed: Info, Pictures, Care & Facts

Doodle breeds are a dime a dozen these days (and for good reason, as they tend towards adorable, intelligent, affectionate, and fun), and...

Irish Setter Dog Breed: Info, Pictures, Care & More

Many dog enthusiasts claim that the Irish Setter is the most beautiful breed to ever exist, due in part to their flowing luxurious...

Pet Euthanasia 101: How & When It’s Done (Vet Answer)

If you’re like many pet owners with an older dog or cat, you’ve probably wondered about what to do at the end of...

9 Off-Leash Dog Parks in Bend, OR You Can Visit in 2025

Although Bend isn’t one of the biggest cities in Oregon, it’s one of the friendliest places when it comes to dogs. Various places...

More related

Great Dane Pit Bull Mix (Great Danebull): Info, Pictures, Care & Traits

The Great Dane Pitbull Mix is a hybrid of the Pitbull and the Great Dane and is commonly called the Great Danebull. The...

Scheduled vs Free Feeding Dogs: Vet-Verified Comparison, Pros, Cons & Facts

You may just scoop up a cup of dry kibble and toss it into your dog’s bowl every day, without giving it a...

How to Train Your Dog to Use Grass Potty Pads: 10 Vet-Approved Tips

Grass potty pads are a great way to protect a lawn or flower beds while providing your dog with somewhere outdoors that they...

Why Is My Dog Peeing a Lot? 9 Vet-Approved Reasons

Disclaimer: This article has been fact-checked by a qualified veterinarian using information available at the time of review. Veterinary medicine is continually evolving...

Keep reading

Can Dogs Eat Goat Cheese? Vet-Verified Nutrition Facts & FAQ

Goat cheese might not be among America’s top 15 most consumed cheeses, but it certainly has its fans. You probably won’t have any problem getting your dog to eat it, but does that mean you should? The answer raises more...

Can Dogs Eat Goat Cheese

13 DIY Dog Bowl Stand Plans You Can Make Today (With Pictures)

Dog bowl stands can make meals more enjoyable for your dog. Raised bowls can help ease joint and neck pain in elderly dogs and those with arthritis. They can also help large breeds eat easier without having to lower their...

black dog eating dr. marty nature's blend dog food

7 Golden Rules for Feeding Your Dog: Vet-Verified Advice & Info

As a dog owner, you know the key to your pup’s good health is proper nutrition. Navigating the different types of dog food out there can be confusing. You want to make sure they are getting what they need, but...

Dog Feeding Schedule

11 Best Dry Dog Foods for Large Dogs in 2025 – Reviews & Top Picks

The market is flooded with hundreds of different dog food brands, all of which are advertising that they’re the healthiest and best fit for your dog. Finding a good brand of dog food is a challenge regardless of what type...

blue fawn pitbull eatin dry kibble from a bowl

Should Dogs Eat the Rainbow? Vet-Reviewed Eating Tips for Canines

Dogs are often considered to be carnivores that require a meat-heavy diet. Still, there are some similarities between a dog’s diet and a human’s diet. However, they are not omnivores like we are. Dogs may benefit from eating the rainbow,...

Colorful assorted fruits and vegetables

Sunday Scaries FOMO Bones Review 2025: An Expert’s Breakdown

“Sunday scaries” is the feeling of dread so many of us get when we realize the weekend is coming to an end and we have to go to work tomorrow. This feeling likely strikes our dogs too, though the more...

Dogster_SAPR_Sunday Scaries Ft img

Can Dogs Eat Croissants? Vet-Verified Nutrition Facts & Alternatives

Although croissants don’t contain ingredients that are toxic to dogs, it’s still not recommended for dogs to eat them. So, you don’t have to worry too much if your dog sneaks a bite of a croissant, but this pastry shouldn’t...

Can Dogs Eat_croissants

Can Dogs Eat Sweet Potato Skins? Vet-Verified Nutrition Facts

Sweet potatoes can be an excellent treat to give your dog occasionally. They’re soft when cooked, tasty, and nutritious. Dogs are omnivores and so can derive important nutrients from both plant and animal sources. As much as dogs benefit from...

Can Dogs Eat Sweet Potato Skins