If there was ever a situation where it would be uber convenient if we could communicate with our dogs, it would be when we’re trying to figure out why they don’t feel well and what’s causing their symptoms.
If only the world were that simple. Unfortunately, until we have the technology to have these hallucinatory conversations with our dogs in real life, it comes down to playing detective when we notice our pups might be having a reaction to their food and its ingredients (or other things they shouldn’t be eating!). How do you know if your dog has a food allergy?
Food Allergy vs. Food Intolerance—What’s the Difference?
The simplest way to understand the difference between an actual food allergy vs. a food intolerance is that a food allergy triggers a response in your dog’s immune system. Their body sees a certain ingredient as an intruder and decides to attack, resulting in a miserable pup and bamboozled pup parent. A food intolerance is a little bit different because it doesn’t actually involve your dog’s immune system, but it may still cause abrupt chaos in their li’l bodies. Unfortunately, it can be very difficult to tell an actual food allergy from an intolerance because many symptoms overlap.
One important feature of a food allergy is that it usually (but not always) involves skin issues. Most commonly, itchy skin and ear infections. How does skin get triggered by the food dogs eat? Their pesky immune system.
Food allergies can look identical to environmental allergies (like pollen or mold) and even other diseases (like skin parasites, hormonal imbalances, medication reactions), which means you and your vet have some detective work ahead of you if your pup has itchy skin!
Skin symptoms that might indicate a food allergy, environmental allergy, or skin disease:
- Hair loss
- Hot spots
- Eye discharge and redness
- Paw and ear infections (inflammation can cause an overgrowth of bacteria in these areas)
- Swelling of face/lips/ears/eyes
Although GI upset is a less common sign of food allergies (diarrhea or vomiting), this is where food allergy and food intolerance overlap and can look identical. Food allergies usually have to do with a protein in the food, whereas a food intolerance can be to literally any ingredient in the kibble.
GI symptoms that might indicate a food intolerance or food allergy:
- Diarrhea/constipation/upset stomach
- Flatulence (not the kind that actually came from you when you blamed your dog)
- Weight loss
If your dog is showing any of these symptoms, it’s important to talk to your veterinarian first. They’ll want to rule out other health problems, possible environmental allergies, or diseases that may cause similar symptoms before focusing on the possibility of a food allergy or intolerance.
Most Common Food Ingredient Triggers
The proteins (beef, chicken, eggs, etc.) in dog foods are usually the culprits when it comes to food allergies. Here’s a list of the most triggering food ingredients:
- Dairy (Usually due to the naturally-occurring sugar, lactose.)
- Wheat (Contrary to popular belief, wheat is much lower on the list of problem-causing foods, though the gluten can sometimes be an issue.)
How To Figure Out What Your Dog Is Allergic To
Although there are allergy tests for dogs in existence, they tend to be inaccurate, so most veterinarians don’t always find them helpful. The most reliable method for narrowing down your dog’s food allergy and sniffing out the trouble-making ingredient is by channeling your inner Sherlock Holmes—become your pup’s own food detective by going through a food elimination trial period.
What Is A Food Elimination Trial Period?
First, you want to confirm that your dog actually HAS a food allergy (and not an environmental one). Your veterinarian will usually suggest a food elimination trial by removing the food you think may be causing the issue. You will substitute with a hypoallergenic diet, which contains proteins in such tiny pieces that the body can’t recognize them enough to react to anything.
You’ll follow this diet strictly for at least 8 weeks, and if your dog’s issues go away, you’ve got your answer! At that point, you may either re-introduce the original diet to confirm your answer (do the problems come back?) or you may be able to introduce a new single-protein diet. Usually, this diet contains a protein you don’t think your dog has ever seen before.
Single-protein commercial diets can’t guarantee that they don’t contain traces of other proteins (analogous to the warning on the chocolate bar that says “processed in a facility that also handles nuts”). Fortunately for a lot of allergic dogs, these traces don’t rock the boat too much. You’ll still want your vet’s input on this. Some of the proteins in these single-protein foods may include:
This second trial goes for about 8 weeks or more, and if the problems do not recur, you’re golden! If they do recur, you’re back to the drawing board and may need to try another diet. Remember, these trials encompass EVERYTHING your dog puts in its mouth. That means you can’t give them treats, table scraps, or anything else that isn’t their trial kibble.
Food Allergy Treatments
Once you and your vet have concluded that there’s a food allergy or intolerance, a simple diet change may be all that’s needed. Topical creams, ointments, antibiotics, probiotics, antihistamines, steroids, or other medications may be suggested to help your pup’s symptoms while you’re in the process of narrowing down the problem.
Dog Breeds Most Susceptible To Allergies
Some breeds are thought to be hereditarily predisposed to developing allergies at some point in their lifetime, but any dog breed can develop an allergy to food. Breeds that are considered to be genetically prone to allergies include:
- Golden retriever
- German shepherd
- American Staffordshire terrier (and other breeds that fall under the “pit bull” umbrella)
- Cocker spaniel
- Shih Tzu
- West Highland terrier
- Yorkshire terrier
This post has been reviewed by Margo Hennet, DVM.
Margo Hennet, DVM, cVMA, and veterinarian at BARK is a canine nutrition, health, & wellness connoisseur. She has a combined 10 years of experience in clinical medicine, research, and education—that’s 70 dog years of know-how—and graduated from Colorado State University as a Doctor of Veterinary Medicine. She completed specialized training in internal medicine prior to working as a general practitioner in Colorado, has authored peer-reviewed publications and textbook chapters, holds certification in veterinary medical acupuncture, and is a member of the American Academy of Veterinary Nutrition and American Veterinary Medical Association.