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

You Can’t Keep A Good Dog Down – Kodah’s Newest Summer Favorite

Hi, I’m Dr. Karyn! Read my introduction to learn more about me and my five funny dogs, Poppy, Bailey, Kodah, Ned, and Fred....

17 Pet Daycare & Dog Boarding Industry Statistics: 2025 Update

Note: This article’s statistics come from third-party sources and do not represent the opinions of this website. Pet daycare and dog boarding services...

Can Dogs Have Prunes? Vet-Verified Nutrition Facts & FAQ

Dogs can have a number of fruits and veggies, as they are omnivores just like us! However, our systems are a lot different....

Can I Put Socks on My Dog to Stop Scratching? Vet Approved Facts & Tips

Dogs scratch themselves for multiple reasons, whether medical or behavioral or just the odd itch. Occasional scratching is normal but if your dog...

More related

How to Dog-Proof a Christmas Tree (8 Easy & Effective Ways)

Christmas is a fun time of the year that is enjoyed by people across the world. Many people with dogs, however, may feel...

Can Dogs Eat Cream of Wheat? Vet-Approved Nutrition Facts & FAQ

The grain-free diet craze is dying down among pet owners, leading some to wonder if dogs can eat grain products like Cream of...

Can Dogs Eat Grits? Vet-Verified Nutrition Facts & FAQ

Grits are a popular breakfast staple, especially in southeastern U.S. states. Grits are derived from white corn kernels and are a quick and...

12 Japanese Chin Mixes (With Pictures)

The Japanese Chin is a dog with an extensive history throughout Asia. Over the last hundred years or so, these adorable pups have...

Keep reading

10 Vet-Verified Foods That Dogs Can Eat on Christmas (With Pictures)

Most dogs are foodies that want to eat whatever you’re eating. So, it’s no surprise if you find your dog sniffing around and staying close by your side while you prepare Christmas dinner. Fortunately, there are several common ingredients that...

Dogs Can Eat on Christmas

What is Kibble Dog Food? Vet-Reviewed Facts & FAQ

A quick glance at the dog food aisle in shops will show you just how many different types of dog foods there are. There are foods with different flavors, nutritional profiles, breed-specific options, and even ones in fancy cans. However,...

dog food, dog bowl, dog kibble

Can Dogs Eat Pringles? Vet-Approved Health Facts & FAQ

Having a dog in the house makes it hard to snack in peace. Whether you’re having a healthy bite or indulging in one of your favorite junk foods, like Pringles, it’s not uncommon to have big doggie eyes begging for...

Can Dogs Eat_pringles

How Much Should a French Bulldog Eat? Vet Explained Puppy to Adult Feeding Guide

Getting a new puppy is always so exciting! You have this little bundle of fur just wanting to eat, sleep, and play with you. As a veterinarian, we often get asked how much food is appropriate to be feeding a...

french bulldog eating or drinking from a bowl

10 Best Foods for Golden Retriever Puppies in 2025 – Reviews & Top Picks

Congratulations on getting your Golden Retriever puppy! You are now one of 69 million American households 1 that have welcomed a dog into their lives. Of course, choosing the right food for your pup is a significant decision. A look...

Golden retriever puppy sitting on bowl

Can Dogs Eat Scallions? Vet-Verified Nutrition Facts & Risks

If your dog licks their lips as your vegetable stir-fry sizzles on the stove, you might wonder if it’s safe to slip them a bite. It might not seem dangerous to give them just a taste, but you should first...

Can Dogs Eat Scallions

What Meat Is Best for Dogs? Top Types Explained

If you’ve spent time looking at dog foods in the pet store recently, then you know just how many protein options there are on the market these days. It can be overwhelming to know what protein to pick for your...

owner feeding shih tzu with dog food

Can Dog Food Cause Urinary Incontinence? Vet Approved Facts & FAQ

Witnessing a dog suffer from urinary incontinence is difficult for a pet owner. Knowing that your pet is dealing with an issue, that in some cases isn’t treatable, is heart-wrenching. While a trip to the vet is necessary when this...

Dog Pee Rug