Is your dog constantly scratching, but there’s no evidence of  fleas? Are they  dealing with ongoing tummy troubles without end? They’re not alone. Food-related issues affect more dogs than most pet parents realize. But here's the thing: not all reactions are actually allergies. Understanding the difference is the first step to helping your dog feel better, and avoid future issues.


Food Allergy vs. Food Sensitivity: What's the Difference?

A food allergy, also known as a “true” allergy, occurs when your dog's immune system overreacts to a specific protein in their food. The body mistakenly identifies this protein as a threat and launches an immune response, which can cause severe reactions. On the other hand, a food sensitivity, A.K.A. an “intolerance,” happens when your dog's digestive system has trouble processing a particular ingredient. This is not an immune response, but rather a digestive one.

The key differences between food allergies and sensitivities are:

  • Reaction severity: Allergies tend to be more severe and can even cause life-threatening reactions, while sensitivities typically result in milder symptoms.

  • Immune system involvement: Allergies involve the immune system, while sensitivities do not.

  • Dose dependence: Sensitivities often depend on the amount of the offending ingredient consumed, whereas allergies can trigger a reaction even with small amounts.

The good news? Both food allergies and sensitivities can be well managed once identified.


Common Dog Food Allergens

So, what are the most common allergens in dog food? The top culprits include:

  1. Beef

  2. Dairy

  3. Chicken

  4. Wheat

  5. Lamb

  6. Soy

  7. Corn

  8. Eggs

Less common but possible allergens include fish, pork, rice, and certain vegetables.

It's essential to note that selecting "grain-free" food doesn't necessarily mean allergy-free, as it’ll depend on your particular pup. However, most allergies are caused by proteins, not grains.


Symptoms of Food Allergies in Dogs

If your dog has a food allergy, you may notice:

  • Skin symptoms: Chronic itching (especially on paws, ears, face, and armpits), redness, inflammation, recurring ear infections, hot spots, hair loss from scratching, and darkened or thickened skin.

  • Digestive symptoms: Chronic diarrhea or soft stools, frequent vomiting, excessive gas, increased bowel movements, and weight loss (in severe cases).

  • Behavioral signs: Restlessness due to discomfort, excessive licking or chewing, scooting, and disrupted sleep patterns.

Keep in mind that seasonal patterns may suggest environmental allergies, while year-round symptoms would be more likely to indicate food-related issues.


Symptoms of Food Sensitivities

Food sensitivities typically manifest as:

  • Digestive upset (more prominent than skin issues)

  • Gas and bloating

  • Occasional vomiting

  • Loose stools

These symptoms often correlate with the feeding of specific meals and could improve when the offending ingredient is reduced or eliminated. And if all of this sounds like no fun, you’re right!


How to Diagnose a Food Allergy

The typical process for diagnosing food allergies is to use an elimination diet, which involves:

  1. Switching to a novel protein (like venison, duck, or rabbit) that your dog has never eaten before.

  2. Feeding only this new food for 8-12 weeks.

  3. If symptoms improve, reintroducing the original protein to confirm the allergy.

There are other pathways to diagnosis, but they are fraught with issues. Blood tests typically have high false positive rates, while saliva tests are not scientifically validated. Hair tests have no real scientific basis, and skin tests only work for environmental allergies. 

But don’t take our word for it. The University of Wisconsin-Madison veterinary care department says, “We do not believe in the accuracy of food allergy tests for animals, and we do not recommend them.” (source) Similarly, the Tufts University School of Veterinary Medicine advises “Saliva and blood tests for food allergies in dogs do not reliably distinguish between healthy and allergic dogs and should not be used for diagnosis of food allergy!” (source)


How to Do an Elimination Diet

It’s not fast, and it might not be easy, but it is the tried and true way to make a real determination of what’s going on with your dog’s issues. To conduct a successful elimination diet:

  1. Choose your diet: Opt for a novel protein, hydrolyzed protein (prescription diet), limited ingredient commercial diet, or homemade diet with veterinary guidance.

  2. Start the 8-12 week trial: Feed only the new food, avoiding treats, table scraps, and flavored medications. Read labels carefully, inform all family members and caregivers, and keep a log of changes in symptoms.

  3. Reintroduction time: If symptoms improve, reintroduce one ingredient at a time, waiting two weeks between each new addition. Monitor for the return of any symptom to identify specific triggers.

Remember, for the most sensitive cases, even one treat can restart the clock, so a total and consistent commitment is necessary.


Managing Food Allergies Long-Term

Once you've identified the allergen:

  1. Avoid it completely: Even small amounts can trigger a reaction.

  2. Read labels carefully: Check food and treat labels to ensure they don't contain the offending ingredient.

  3. Inform caregivers: Share your dog's allergy information with anyone who cares for them, and avoid any treats or new foods if you don’t know the exact ingredients. (Sorry, delivery drivers!)

Safe alternatives could include focusing on single-protein limited ingredient diets, switching to novel protein options, sourcing hypoallergenic treats, and making homemade treats.


Managing Food Sensitivities

Food sensitivities may not require complete elimination of the offending ingredient. Instead:

  1. Limited exposure: Reduce the amount of the ingredient to a level that doesn't trigger symptoms.

  2. Digestive enzymes: Consider adding digestive enzymes to support your dog's digestive system.

  3. Probiotics: Support gut health with probiotics.

  4. Gradual introduction: Introduce new foods gradually to monitor for adverse reactions.


When to See Your Vet

If you notice:

  • Persistent symptoms despite diet changes

  • Severe reactions (facial swelling, difficulty breathing)

  • Weight loss or failure to thrive

  • Secondary infections from scratching

  • Questions about the elimination diet

  • Need for prescription diets

Your veterinarian should be your partner and main advisor in this process. Don't go it alone!


Common Mistakes Pet Parents Make

It’s tempting to try quick fixes, or to make “just-this-once” exceptions, but try to avoid these common mistakes:

  1. Switching foods too frequently (doesn't give enough time to assess)

  2. Giving treats during the elimination diet

  3. Assuming grain-free solves everything

  4. Not reading treat labels

  5. Giving up too soon on the elimination diet

  6. Self-diagnosing without veterinary input


You’ve Got This

Food allergies and sensitivities can be frustrating to navigate, but with patience and the right approach, you can find what works for your dog. By understanding the differences between food allergies and sensitivities, identifying common allergens, and working with your veterinarian, you can help your dog live a happy, healthy life.

P.S. Want to learn more about reading pet food labels to avoid allergens? Check out our label-reading guide.