by Zack Wright
Contents
What Is a Food Allergy and What Causes It?
How Common Are Food Allergies in Dogs?
What Are Signs That My Dog Has Food Allergies?
Are Certain Dog Breeds More Prone to Food Allergies?
What Foods or Ingredients Cause Allergies in Dogs?
How Are Food Allergies Diagnosed in Dogs?
Food Elimination Trials
Do Other Testing Methods For Food Allergies Work?
How Are Canine Food Allergies Treated?
What Foods Are Good for Dogs with Food Allergies?
Are Raw Food Diets Good for Dog Food Allergies?
Can Lavengel® Help With Food Allergy Rashes and Irritations?
Canine Food Allergy FAQs
Thought for Food
A simple truth of life is that what we eat plays an immense role in our overall health. Turns out, the same goes for our fuzzy, barking food supervisors, too, and dog food manufacturers have taken notice.
The pet food industry has exploded in the last 30 years, grossing over $64 billion in sales in 2023 the United States alone, according to Statista. Retail sales of dry and wet dog food nearly broke $10 billion last year (2023) - and that doesn't even include treats!
These days, our precious little alternative children have about as many different food options as we humans do. We can choose everything from "grain-free" and "raw" to hypoallergenic and prescription alligator or kangaroo diets (yum?).
While the majority of this variety is created simply for the sake of making money, different diets have indeed arisen from nutritional needs due to age, health issues (such as arthritis or diabetes), and food allergy concerns. Since the title of this article deals with **checks notes** food allergies, let's focus on those.
What Is a Food Allergy and What Causes It?
A food allergy is the body's immune system "overreacting" to one or more specific dietary proteins or carbohydrates. The immune system sees the ingredient as a foreign substance and a "threat," then it produces antibodies (immunoglobulin, in nerd speak) to attack that substance.
This army of antibodies creates inflammation, which can have wide-reaching effects on the body and create gastrointestinal problems (indigestion, diarrhea, vomiting, etc.), dermatological problems (redness, itching, ear infections, etc.), and/or increased fluid production.
Antibody production is actually required for an allergy to develop, and this process takes some time. Food allergies in dogs aren't quite what we would picture when we think of "allergic reactions," where something happens almost instantly after a new food is tried for the first time.
Food allergies tend to develop over a period of weeks, months, or even years as the body is continuously fed and exposed to the same food and ingredient(s).
Food Allergies and Food Intolerances
One last tidbit: Food allergies and food intolerances (such as lactose intolerance) seem similar, but they are not quite the same.
Food allergies are mediated (brought about) by the immune system reacting inappropriately to a normally harmless substance. Food intolerances involve the inability to adequately digest something, and discomfort tends to happen quickly after eating the foods.
That said, both food allergies and intolerances are generally treated by avoiding the troublesome foods or ingredients.
How Common Are Food Allergies in Dogs?
There is disagreement among professionals as to just how common food allergies are in dogs. Some say that they affect less than 1% of the dog population, while others believe that they are far more prevalent than that, with 6% of all skin diseases and 20% of all allergic dermatitis being attributed to an adverse food reaction.
What makes it so difficult to tell are some compounding factors:
- There is no simple test for food allergies at this time. Blood, serum, and saliva tests have been tried and found to be inconclusive (more on this later).
- The exact mechanism by which the immune system deems a normally innocuous protein as "harmful" is not fully understood. Simply put, scientists don't yet know why the body decides to "hate" something, especially after being exposed to it for weeks or years, nor why it affects certain dogs and not others.
- It is very possible for a dog to have more than one allergic reaction happening at one time, such as from seasonal, airborne, or environmental allergens like grass, pollen, or dust mites. Since food allergies can exhibit some of the same symptoms as other allergies (itching, redness, atopic dermatitis, watery eyes, etc.), it can be tough to distinguish between a food allergy and a different allergy.
Photo: Australian Shepherd paw with redness and hair loss due to itching from allergies
What Are Signs That My Dog Has Food Allergies?
Food allergies can come with classical skin allergy symptoms such as itching, redness, and inflammation, and these are typically (but not always) limited to the face, ears, belly, anus, and feet. The itching is usually severe, and dogs will often lick, chew, and scratch until the skin is damaged, and hot spots, bald patches, and bacterial infections form.
With the itching being so bad, it's often important for vets to rule out sarcoptic mange, also known as scabies, which is caused by microscopic mites that burrow in the skin and multiply. A scabies infestation can exhibit the same itching pattern (especially on the feet and face) as a bad food allergy.
Distinguishing Between Food Allergies and Other Allergies
That said, there are a few factors that can help discern between a food allergy and another allergy:
- The itching is not seasonal, meaning it doesn't seem to start and stop as the weather changes. This can be difficult to tell in climates where the weather is warm or moderate year round.
- The itching pattern, or area, is consistent with food allergies: face, feet, belly, and itchy booty spout.
- The itching began when the dog was less than 6 months old, or older than five or six years old. The young age might indicate a hereditary disorder, whereas a more mature dog would have had time to develop a food allergy with consistent feeding. Also, with a more mature dog, the owner would have had some time to observe any seasonal allergy patterns.
- Your dog has frequent, recurring ear infections.
- Sarcoptic mange has been ruled out. These mites can "hide" and be tough to find and diagnose, but they tend to always respond to effective treatment. If the mange treatment has been applied with no response, a food allergy is possible.
- Prescribed corticosteroids have not helped with the itching. These may or may not work on food allergies, but they nearly always help for other allergies.
- Your dog is having gastrointestinal issues like diarrhea or vomiting.
- Though these are extremely uncommon, seizures can be linked to a food allergy.
Are Certain Dog Breeds More Prone to Food Allergies?
Food allergies can occur in any breed of dog, though some breeds are more likely to have them, such as:
- Labrador Retrievers
- Golden Retrievers
- English Springer Spaniels
- Cocker Spaniels
- Collies
- Miniature Schnauzers
- Shar Peis
What Foods or Ingredients Cause Food Allergies in Dogs?
Virtually any protein, carbohydrate, or additive can bring about an allergy in your dog. The most prevalent food allergens in dogs are animal-based proteins, with beef, dairy, and chicken at the top. Plant-based proteins are less common but also have a presence on the allergen list.
Animal-Based Food Allergens Known to Affect Dogs
- Beef (most common)
- Dairy products
- Chicken
- Lamb
Less Frequent Proteins:
- Eggs
- Pork
- Fish
Plant-Based Food Allergens Known to Affect Dogs
- Wheat and wheat gluten (most common)
Less Frequent Proteins:
- Soy
- Rice
- Corn
How Are Food Allergies Diagnosed in Dogs?
Unfortunately, this isn't a straightforward process, and involves diving into your dog's history.
Ruling Out Other Skin Conditions or Diseases
As with any good vet visit, your dog's records will be consulted, questions will be asked, and your vet will do a general physical examination of your lovable bark machine.
From there, your vet may seek to run tests to make sure the issue isn't a different condition with similar symptoms, such as:
- Fleas
- Mange mites
- Ringworm
- Yeast infections (Malassezia)
- Bacterial infections (pyoderma)
- Environmental allergies, from pollen, dust mites, mold, etc.
If all of these are ruled out, a food allergy may be suspected. However, it is important to remember that it is possible for more than one thing (including food allergies) to be causing symptoms.
Food allergies and the irritation they bring about - plus all the chewing and scratching - create a prime setup for a bacterial and/or yeast infection.
Food Elimination Trials
As of writing this article, the gold standard for accurately diagnosing canine food allergies is a food elimination trial.
A food elimination trial involves strictly feeding your dog a specific hypoallergenic diet for 8 to 12 weeks. Such a period of time will allow time for the immune system to decide if it "likes" the new food or not.
During the trial, owners must only feed the prescribed diet; even treats and flavored medications or supplements should be avoided. These diets feature a single protein source that is either hydrolyzed or novel (new) to the dog.
Hydrolyzed Protein
When a protein is "hydrolyzed," it goes through a process called hydrolysis that breaks the protein down into super-small particles. This prevents the protein from binding to a receptor that sparks the improper immune response. Some examples of veterinary hydrolyzed diet food products are:
- Hill's® Prescription Diet z/d®
- Royal Canin® Hypoallergenic Hydrolyzed Protein®
- Royal Canin® Anallergic™
- Blue Buffalo® HF
- Purina® ProPlan Veterinary Diets HA Hydrolyzed®
Novel Protein or Carbohydrate Diets
These diets offer an unusual, new protein source with limited ingredients. These can get pretty wild, and some of those sources can include rabbit, duck, peas, potatoes, venison, kangaroo, or even alligator or crocodile. Some product examples (so you know I'm not kidding) are:
- Hill's® Prescription Diet d/d®
- Royal Canin® Selected Protein PD®
- Rayne Nutrition® Kangaroo-MAINT™
- Rayne Nutrition® Rabbit-MAINT™
- Rayne Nutrition® Crocodilia-MAINT™
Novel diets can even be home-prepared, but they should be formulated by a veterinary nutritionist. They will also likely require a supplement to meet the dog's complete nutritional needs.
The Often Neglected Retrial Process
Once the 8 to 12 week trial period is up, it is important that the dog's previous food is given to them for a week to see if the allergy flares back up. Because the immune system has already established a "dislike" for that food, the symptoms should reappear within the week - sometimes even within hours.
This is a very important step that is often overlooked.
Most people, upon seeing their dog's symptoms clearing up, immediately decide that the problem has been found, and they avoid the retrial of the old food.
Sometimes that works, and sometimes it doesn't.
It's important to note that during this re-challenge, you do not feed the old food until the previous symptoms get bad, but until the first sign of them, which should manifest within the first few days.
This truly lets you know that, yes, that old food is bad juju after all. Further, moving on before doing a retrial of the old food fails to narrow down what ingredient your dog is allergic to.
For example: What if it wasn't the food causing the allergy, but something in the treats or the flavoring used in their supplements?
What About Blood, Saliva, Skin, or Hair Tests for Diagnosing Food Allergies?
For food allergies, don't waste your money. You can keep scrolling unless you feel like reading why.
As mentioned previously, there isn't a simple test for identifying food allergies in dogs at this time. Studies that have attempted to use blood, serum levels, hair, saliva, and skin biopsies to rule out food allergies have found them to be inconclusive.
Not only that, but they are rather expensive, and the test results can even hinder the diagnosis of true food allergies. Until the specific mechanism(s) that bring about such an immune response are identified, the only effective method available is a food elimination trial.
Blood Tests
Blood tests can detect antibodies against certain proteins, but they can't determine if it means there is an allergy or if the dog has simply eaten that protein recently.
Also, a dog's body may alter a protein during digestion, and that new, or altered protein could be what causes the allergy. It's not possible to predict how a protein could be altered, so a test cannot feasibly be created.
Serum Level Tests
When the immune system fights an allergen that it deems "bad," it produces antibodies, also called immunoglobulin. In response to allergy sensitization (i.e., "We found an allergy, let's attack it!"), it is more specifically immunoglobulin E (IgE) that is produced.
Serum level tests can examine IgE levels to confirm that there is an allergy, but they can't accurately determine what is causing it. Studies attempting to correlate IgE levels with food allergies gave a wide range of results, rendering the method untrustworthy in screening. That said, the serum tests do tend to be more helpful in confirming an environmental allergy.
How Are Canine Food Allergies Treated?
The answer should be pretty obvious: Feed your dog a different diet that does not contain the offending ingredient.
Once the allergen is removed, your dog's symptoms should clear. Your vet may prescribe antihistamines, steroids, or other allergy medications to alleviate severe symptoms in the meantime.
It's worth noting that dogs with food allergies are likely to also have environmental allergies as well, so prescription meds along with healthy supplements (such as omega fatty acids) may be recommended. Undergirding all of it, of course, is a healthy, balanced diet.
What Foods Are Good For Dogs With Food Allergies?
First of all, there is no "best diet" for dogs with food allergies. Each dog is unique, and allergies are unique to each dog.
The best diets will be optimized for complete, well-balanced nutrition (lots of protein, vitamins, and minerals), and contain limited ingredients. Obviously, they will also not contain the ingredient(s) that your dog's immune system wages an insurrection against.
Beware Marketing Phrases on Dog Food Packaging
Keep an eye out for diets that are actually formulated by veterinary nutritionists. The dog food aisle is full of choices, colors, and clever marketing phrases (like "grain-free") that mean little when it comes to what you are providing your dog at the micronutrient level.
Beware Foods Produced Under Lax Protocol
Another thing to consider is that many cheaper foods at the pet store - even single-protein diets - are not manufactured with the same stringent protocol as true prescription diets.
Tests done on these cheaper foods found additional proteins - not on the labeling - at levels that can spark food allergies. It is likely that this cross-contamination happens as different foods are produced in one facility on the same, or nearby, equipment, and these foreign ingredients find themselves "spicing up" the wrong foods.
Are Raw Food Diets Good for Dog Food Allergies?
Yes, it is possible, but it's not going to apply to all dogs. Every dog is different, and no one single diet is best.
There is no shortage of stories on the internet declaring that a raw food diet "changed their dog's life." I have seen firsthand a relative's senior dog go from traditional store-bought kibble to a raw food diet, and within a few months, he looked like a completely different dog - for the better.
In theory, a raw food diet would virtually eliminate a food allergy by being a single or limited protein source free from potential contaminants from processing. However, there are a few things to consider:
- Dogs are omnivores, not carnivores. Like the creatures that domesticated them, they do better with a balanced diet, including some veggies and carbs (but not too many).
- Only feeding your dog a single protein source does not give them a balanced diet, so supplementation would be necessary.
- Raw or undercooked meat contain bacteria that your dog's digestive or immune systems may not be able to handle. Though they may have been at one time, dogs aren't wolves any more, and their stomachs have changed as time and generations have passed.
- Where you acquire the food matters, as contamination can happen in suppliers with less stringent standards.
Raw food diets can be a touchy subject among veterinarians and veterinary nutritionists. They tend to side with science (a good thing, to be sure), which suggests that conclusive research on the benefits of raw diets is lacking.
At the end of the day, your vet wants what's best for your dog and offers suggestions based on their knowledge, experience, and the information you provide them. Their recommendations should always be respected and weighed heavily.
But ultimately, it's up to you, the owner, to decide how to feed and care for your fuzzy freeloaders.
Can Lavengel® Help With Food Allergy Rashes and Irritations?
So glad you asked. It sure can!
Lavengel® can be a big help with relieving and healing rashes or itchy spots that arise from food or environmental allergies. We have had many customers tell us that our gel has helped prevent itchy spots due to allergies from worsening into hot spots or infections.
Lavengel® packs a prescription punch without the prescription. It's made with ingredients you can pronounce, it's safe for dogs to lick (unlike prescription ointments), and it's backed by real microbiological research and nutrition.
Canine Food Allergies FAQs
Can food allergies in dogs be cured?
No, there is no current cure or vaccine for dog food allergies. They will only clear up by feeding your dog a food that does not contain the ingredient(s) that they are allergic to.
Is There a Test for Food Allergies in Dogs?
A food elimination diet trial is the only accurate way to diagnose a food allergy in your dog. There is no simple "sample" test at this time, whether blood, serum, saliva, skin biopsy, or hair test.
What Is the Most Common Food Allergy in Dogs?
Dogs are most commonly allergic to proteins, especially animal-based proteins such as beef, dairy, and chicken. Plant-based proteins such as wheat are less common but also possible.
Do Grain-Free Diets Help with Dog Food Allergies?
Not necessarily. The majority of food allergies are a reaction to a meat protein, not a plant protein. On top of that, grain-free diets deny dogs (omnivores) with a good, legitimate source of nutrients that they need. If you find that your dog is allergic to a plant protein (such as wheat), it is best to simply avoid that specific allergen rather than kick grains altogether.
What Are the Symptoms of Canine Food Allergies?
- Moderate to severe itching, especially on the feet, face, belly, and anus
- General redness of the feet, with frequent licking and chewing
- Frequent ear and skin infections
- Less common, but possible: gastrointestinal upset, diarrhea, or vomiting
What Is the Best Food Diet for Dogs with Food Allergies?
Each dog is different, and allergies are unique to each dog, so there is not a single diet that works for every dog.
Diets that are commonly recommended for dogs with food allergies are hydrolyzed protein diets and novel (new/different) protein diets. The best diet for your dog will be one that covers their nutritional needs and does not contain the ingredient(s) that upset their immune system (that is, cause an allergic reaction).
Can My Dog Develop Other Food Allergies?
It is possible for another food allergy to develop after resolving the first, but there's no good way to be certain.
Food allergies in dogs develop over time - after months or years of exposure. The exact mechanism by which a dog's immune system "decides" to react to certain substances that seemed to be "fine" before (or fine for other dogs) is not entirely understood as of today (2024).
Are My Dog's Food Allergies Hereditary?
Given that any immune system is acquired from the biological parents, it makes logical sense that heredity could play a part in allergies being passed down, but it is not guaranteed. Some dogs may have bad allergies, but other pups from the same litter may not.
Canine Food Allergy Resources
- Veterinary Partner: Food Allergies in Dogs and Cats
- VCA Animal Hospitals: Food Allergies in Dogs
- MedVet: Food Allergies in Dogs
- PetMD: Food Allergies in Dogs
- PetMD: How to Tell If Your Dog Has Food Allergies
-
Assessment of Dog Owners’ Knowledge Relating to the Diagnosis and Treatment of Canine Food Allergies
S. Tiffany, J.M. Parr, J. Templeman, A.K. Shoveller, R. Manjos, A. Yu, and A. Verbrugghe; Canadian Veterinary Journal, Volume 60(3): 268-274, March 2019
