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If your dog is always licking their paws, your cat gets ear infections left and right, or your pet seems itchy no matter what you do, it’s normal to wonder: “Is it the food?”

Pet food allergies are real, and they can cause a variety of symptoms. But they’re also one of the most misunderstood topics in pet health, and the amount of conflicting advice online can make it hard to know what’s actually true.

At Haarstad Veterinary Dermatology, we work with dogs and cats who struggle with itchiness, ear infections, recurrent skin infections, and allergy symptoms every day. And one of the most common themes we see is pet owners who have already tried multiple foods, switched to grain-free diets, or cut out certain ingredients,  but their pet is still uncomfortable.

So we’re here to clear up some of the most common myths about pet food allergies, and talk about what actually helps.

What do food allergies look like in pets?

Most people think that a food allergy causes vomiting or diarrhea. That’s possible, but in many dogs and cats, food allergies show up on the skin first.

Common signs can include:

• Itching or chewing (especially at their paws, face, belly, or ears)

• Recurrent ear infections

• Red skin or “hot spots”

• Hair loss or inflammation of the skin

Some pets can also have issues with GI symptoms like vomiting or diarrhea, but the skin signs are most common, which is why food allergy conversations often overlap with dermatology. Food reactions often look like a skin disease before they show up as a digestive issue. If you’d like a deeper explanation of symptoms and what a true food allergy looks like, you can also read our full blog on Food Allergies in Pets: Symptoms, Diagnosis, and Advanced Treatment Options.

Myth #1: “Food allergies are the most common reason pets itch.”

Truth:   Food allergies are real, but they’re not the most common cause of itchiness.

Most itchy dogs and cats are dealing with something else: environmental allergies, flea allergy dermatitis, bacterial or yeast infections, or a combination of things. Food allergies are a possibility, but they are not the first direction we turn for the average itchy pet.

Why this matters:

If you switch foods repeatedly without addressing infections or environmental allergies, your pet could continue to suffer because the food isn’t the main issue.

Myth #2: “If my pet has a food allergy, they’ll have diarrhea.”

Truth: Food allergies in dogs and cats often cause skin and ear issues more often than digestive upset.

Some pets do experience vomiting or diarrhea as well, but many don’t. The more common pattern is chronic itching, recurring ear infections, skin inflammation, or constant licking and scratching.

Why this matters:

A pet with normal stools can still have an allergy to pet food. And a pet with digestive upset doesn’t automatically have a food allergy,  there are many potential causes of GI symptoms.

Myth #3: “Grain is usually the problem.”

Truth: Grain allergies are possible, but they’re much less common than people think.

This myth is online everywhere, and it makes many pet owners assume that “grain-free” is the answer when deciding which pet food is best. In actual food allergies, the triggers tend to be the protein, like beef, chicken, dairy, or egg.

This doesn’t mean grain is never the issue, but it’s much less common than you think.

Why this matters:

Switching to grain-free isn’t a good way to diagnose or treat a food allergy, and it often takes focus away from the bigger goal: identifying the actual trigger.

Myth #4: “Chicken causes food allergies in pets.”

Truth: Chicken can be a trigger (as can other animal proteins),  but it isn’t automatically a problem, and it isn’t “bad.”

We hear this one all the time:  “My dog is allergic to chicken.”

Chicken is one of the most common forms of protein in pet foods, treats, and chews. And because food allergies often develop after repeated exposure over time, chicken can become a trigger for some pets simply because it’s so widely used.

But here’s the point:

Chicken is not a problem for most dogs and cats. Many pets eat chicken for their entire lives with no allergy issues at all.

Why this matters:

Avoiding chicken without a plan can lead to a cycle of food switching that doesn’t solve the problem,  especially if the new food still contains chicken fat, chicken flavoring, or cross-contact in its manufacturing.

Myth #5: “My pet reacted right after I switched foods, so the new food must be the problem.”

Truth: Food allergies usually develop over time, not overnight. Flaring from eating an allergy trigger can happen within hours or can take days once the allergy develops. Also, the food change can be coincidental to the actual reason for a flare, like a change in season for pets with environmental allergies.

Food allergies tend to develop after long-term exposure to a specific ingredient. So it’s possible for a pet to have been eating the same food for years and suddenly become allergic to it.

So why do allergy symptoms sometimes seem to flare right after switching foods?

• The allergy may already have been developing prior to the switch

• The new food could have ingredients your pet has eaten before

• An unrelated factor (seasonal allergies, infection, stress) may have flared at the same time

Why this matters:

Noticing a flare after switching foods still does not identify what the pet is reacting to. There are typically many ingredients in pet food and a pet could even be allergic to more than one ingredient. 

Myth #6: “A blood test can tell me what food my pet is allergic to.”

Truth: There is no single blood test that will diagnose food allergies in pets.

It would be great if a simple blood test could tell us exactly what a pet is allergic to. But currently, blood and skin testing are not reliable for diagnosing true food allergies.

The most accurate method is still a strict elimination diet trial with guidance from your primary vet or veterinary dermatologist.

Why this matters:

When pet owners rely on testing that isn’t reliable, they end up avoiding a long list of foods unnecessarily,  and their pet may still itch because the true trigger wasn’t identified.

Myth #7: “If a food allergy is real, it should be easy to figure out.”

Truth: Food allergies can be tricky because they look like other skin conditions.

Food allergy symptoms can look just like:

• environmental allergies

• bacterial or yeast infections

• flea allergy dermatitis

Some pets even have more than one issue at once.

That’s why it’s so common for owners to feel stuck. Even when food is part of the puzzle, it might not be the only piece. Up to 25% of dogs can have both food and environmental allergies they deal with.

Why this matters:

A plan that addresses the whole picture,  skin, ears, infections, and diet, will bring the fastest relief.

Myth #8: “If I suspect a food allergy, switching my pet to another over-the-counter food will help me rule out what the allergy is.”

Truth: Some pets have a mild enough food allergy that switching to another over-the-counter diet seems to help,  especially if the new food happens to avoid the ingredient that was triggering symptoms. However, even if your pet improves, it doesn’t rule out a food allergy. Many over-the-counter diets still share common proteins (like chicken, beef, or egg), include trace ingredients, or are made in facilities that process multiple proteins. That can make it difficult to know what your pet is actually reacting to.

This is where a consultation and guidance from your vet becomes important. They can help you choose the right approach and, if needed, guide you through a structured elimination diet using prescription diets that are made specifically for allergy testing.

Why this matters:

Switching foods over and over can create a lot of confusion, and it can delay real answers. If symptoms come and go with different diets, it might be tempting to assume you’ve “solved it,” but flare-ups often come back because the real trigger hasn’t been identified. A structured plan helps you avoid the cycle of trial-and-error and gives you a better, more reliable path to long-term relief.

What should you do if you suspect a pet food allergy?

If your dog or cat is itchy, has chronic ear infections, or keeps flaring even with treatment, here are some helpful things you can do:

1. Check in with your primary vet or veterinary dermatologist to rule out common causes first. A vet will check your pet for fleas, infections, ear concerns, and potential environmental triggers.

2. If recommended, start a structured diet trial. Don’t try to do a random food switch, have a plan with strict guidelines. We recommend talking with your vet, rather than trying to figure it out on your own. 

3. Track symptoms. Keep simple notes like paw chewing, ear redness, scratching level. Even simple notes can help.

4. Avoid switching foods without a structured plan. Food hopping can make it harder to figure out what the actual triggers are.

How Haarstad Veterinary Dermatology can help pets with food allergies

Food allergies can be frustrating,  not just for pets, but also for their owners trying to help them. Our role is to make the process clear and more manageable, while treating any underlying skin or ear problems that may be contributing.

At Haarstad Veterinary Dermatology, we can:

• Assess whether or not a food allergy is likely 

• Treat bacterial and yeast infections that can occur alongside allergy disease

• Create an elimination diet that will work for your pet and your lifestyle

• Help you identify “hidden” triggers that can interrupt a true trial (such as treats, chews, etc.)

• Build a long-term plan once triggers are identified, so your pet will be comfortable year-round

Once we confirm whether food is truly the trigger (using a strict diet trial), we can start bringing treats back into the picture. The key is to reintroduce items one at a time, so if your pet does react, we will know what caused it, and you don’t have to avoid everything forever.

Our goal is to help your pet feel better,  and to help you understand that you’re taking the appropriate steps.

Quick FAQ: What pet owners ask most

Can chicken cause pet food allergies?

No,  chicken itself does not cause an allergy. While chicken can be a trigger for some pets, simply eating chicken won’t create an allergy, and most pets tolerate it just fine. It’s also important to remember that many foods labeled “chicken” contain multiple ingredients, and the real problem may be something else in the recipe (like beef, dairy, eggs, or additives), not the chicken. The best way to know for sure is through a structured diet trial, if your veterinarian recommends one.

How long does a diet trial take?

Most pet food trials need at least 6–8 weeks of consistency to give a true answer.

What’s the best test for food allergies?

A strict elimination diet trial is the most accurate way to identify pet food allergies.

If you suspect your dog or cat has a food allergy, you’re definitely not alone. It’s important, though, to separate what’s popular online from what actually works.  

Food allergies can definitely cause constant itching and ear issues in dogs and cats. The most effective way to help them is to schedule a visit to your primary vet or veterinary dermatologist for recommendations for what is best for your pet.

If your pet is struggling, we’re here to help, give us a call today!