Dog food allergies and food sensitivities (or intolerances) are two food-related issues with similar symptoms, but very different causes.

Seeking a Proper Diagnosis

Without proper diagnosis, pet parents might be quick to assume that their dog’s symptoms are due to a dog food allergy and attempt to solve the issue by feeding them a gluten-free, limited-ingredient, or grain-free dog food. Chances are, switching them to a diet like grain-free dog food will not cure the dog food allergy symptoms. I’ll talk about ‘why’, in a moment.

The first thing that’s important to rule out are potential environmental allergens. Factors like pollen, grasses, mold, and fleas are all possible culprits causing your pup to itch, scratch, and chew excessively. In fact, reactions to food only account for about 10% of all “allergies” seen in dogs. On top of that, a dog food allergy isn’t the most common food-related issue—food sensitivity is more likely at the root of their discomfort. So, it’s important to differentiate ‘true’ food allergies from food sensitivities to best avoid skin and digestive upsets.

I’ve had pet parents come to me with the question, “Should I switch to grain-free dog food if my dog seems allergic to their food?”  My answer is always, no. That’s not the best first step to take. If you suspect that your pup has a dog food allergy (or sensitivity), don’t rush out and pick up a dog food that claims to be allergen-free (gluten-free and grain-free included) and expect positive results. Even food labeled “limited ingredients” won’t likely address your dog’s symptoms because it won't likely address the real problem.

Occasionally, a dog may be allergic to a specific grain, but this is less common than an allergy to an animal protein. Grains are rarely the source of food allergies (and food sensitivities).

It’s important to work with your veterinarian to discover the source of your dog’s symptoms. It’s entirely possible the issue is completely unrelated to the diet. A problem with their health may be overlooked if focusing on diet as the root before ruling out all other potential causes. So a correct diagnosis is very important.

The Difference Between Dog Food Allergies and Sensitivities

Food Allergy: An allergic reaction to food happens when your dog’s immune system misidentifies a protein in their diet as an invader and mounts an attack.

Food Sensitivity: A non-immunologic adverse response to food (usually gastrointestinal) due to an inability to metabolize an ingredient properly.

These two food-related issues share many of the same symptoms, but most often an allergy causes itchy skin or ear and skin infections due to the body’s natural inflammatory response. Less frequently, pups will have a gastrointestinal reaction causing vomiting or diarrhea. But some unlucky pups will have both skin and tummy issues related to their food allergy.

If your dog suffers from a food sensitivity (as opposed to an allergy), they’re much more likely to experience gastrointestinal issues (diarrhea, vomiting, gas, lack of appetite, and weight loss) due to an inability to process an ingredient properly. They may also have intermittent itchy skin or redness that seems to resolve only to return again.

In most cases, it’s the meat and dairy protein in their diet that’s at the root of food-related issues.

Pinpointing Your Dog’s Food Allergen

The most accurate way to pinpoint an allergen is through an elimination trial (aka limited-ingredient diet). But remember, before testing for food-related issues, work with your veterinarian to rule out all other potential health problems.

Once you’ve narrowed it down to food as the culprit, you’ll place your pup on a strict diet which includes removing or limiting treats, flavored medications, and flavored toothpaste in addition to their meals.

The idea behind the diet is to stabilize your pup’s system and then slowly introduce ingredients back into mealtime while watching for a reaction.

There are a few ways to approach the elimination trial:

  1. Carefully prepare a home-cooked diet designed by a board-certified pet nutritionist, typically containing one protein and one carb (your pup has never eaten before), plus essential fats, vitamins, and minerals.
  2. Serve a vet prescribed hydrolyzed diet, where the proteins are broken down into tiny pieces that will not likely cause a reaction.
  3. Feed your pup, a ‘novel ingredient’ diet using less-common proteins like venison, rabbit, or duck instead of beef or chicken. This should also be prescribed. It’s been shown there are contaminants in many OTC (novel protein diets) that may cause a reaction in very sensitive dogs.

Your pup will need to remain on this restricted diet for at least a month (to clear their symptoms) before reintroducing ingredients one at a time. But to be safe, it’s best to remain on the diet for 12-16 weeks because different symptoms clear at different rates. And the type of elimination trial diet you put your dog on will also impact how quickly the symptoms clear. The immune system takes a while to rest and regroup.

  • It takes 1 month to clear gastrointestinal symptoms
  • It takes 8-12 weeks to clear skin irritation symptoms (if using a hydrolyzed diet)
  • Ultamino diet takes 6-8 weeks
  • A novel protein diet should last 12-16 weeks

A common reason for a missed diagnosis is ending the food trial long too soon. Most dogs will not even begin to show improvement until the 4-week mark.

And be sure to test all of the ingredients they normally eat and not stop the test once you’ve identified one culprit. Where there’s one allergen, there may be more. It’s estimated that more than a third of dogs with a food-related issue will react to more than one ingredient. 

Managing Your Dog’s Diet

Now that you’ve identified the foods your dog is allergic to, simply eliminate them from their diet. There are a few ways to control the ingredients.

1. Make them a homemade diet.

If you decide to go the homemade route, it’s essential that your recipe has the proper balance of protein, calories, carbohydrates, vitamins, and minerals. It’s complex and should be formulated by a pet nutritionist.

2. Purchase food from the pet store.

This can be a little challenging; one thing to look for is the ‘real’ protein source. If you see the word flavor, chances are the main protein is something other than what is promoted on the label. If you’re uncertain about the ingredients, contact the company. If they don’t clarify, don’t purchase the food. Even a small amount of an allergen can be enough to effect a sensitive pup.

3. Purchase food specifically formulated for your dog.

There are a handful of companies, like Puppo, that formulate customized dog food to support each individual pup’s sensitivities and dietary restrictions. Talk to a pet nutritionist to find out if their product is right for your dog.

While identifying what your sensitive (or allergic) pup is reacting to may seem a bit daunting, it’s one of the most important things you can do to support their health and wellbeing. And thankfully, finding a healthy dog food, packed full of all the nutrition your pup requires isn’t as tricky as it once was.