Common food allergies in dogs, explained by a vet

As many of us can confirm, allergies are super unpleasant. In basic terms, allergies are caused by the body mistaking a foreign substance as harmful, even if it isn’t. The immune system responds by creating antibodies to attack the antigen. This reaction leads to symptoms like sneezing and runny eyes, itching, swelling, and rashes, and/or gastrointestinal distress.

Unfortunately, allergies are among the common conditions affecting both humans and dogs alike. While human allergies affect up to 50 million Americans each year, the estimates for dog allergies are harder to calculate. One reason is that they’re often mistaken for food sensitivities, which may involve similar symptoms, but don’t cause immune responses.

Dogs with environmental allergies can also show the same symptoms as those with food or flea allergies (like skin infections). It can be challenging to determine the cause of the allergy, especially since environmental allergies are far more common than food allergies. However, true food allergies do exist in dogs, and they can be dangerous if left untreated.

Understanding how to recognize and treat your dog’s food allergies is important for any pet owner, and the knowledge may just end up saving your dog’s life.

While true dog food allergies may only affect less than 5% of the canine population, it remains an important issue to monitor. Naturally, dogs can’t communicate their feelings, so it’s up to owners to keep an eye out for potential allergies. This is especially important if you suspect an allergen may be an ingredient in your dog’s daily food or treats. Below are some of the frequently reported culprits for food allergies in dogs:

*numbers based on 2017 study from BMC Veterinary Research

This data does reveal some trends about dog food allergens. For example, dogs with food allergies are usually allergic to a type of protein in their diet. Beef and chicken are the most common allergen among dogs with food allergies. However, up-to-date research remains scarce, and there’s still much scientists wish to learn about the causes of food allergies in dogs.

While more research is needed, there’s also some evidence that certain breeds may be more prone to food allergies than others. These include:

• Fox red Labrador retriever
• West Highland white terriers
• Cocker spaniels

Diagnosis of food allergies in dogs begins first with recognizing symptoms. Since some symptoms may signify other health issues or conditions, besides allergies, it’s important to closely monitor the extent and severity. As always, owners should plan to visit a veterinarian or specialist if symptoms persist.

• Itchy skin (also known as pruritus). Itching is the most common symptom of allergies in dogs, and food allergies are often to blame.
• Itchy paws. Itchy paws may be caused by environmental irritants like pollen and dust mites, but allergies to foods can also lead to itchy paws in some dogs.
• Ear infections. Fifty percent of dogs with food allergies have recurring ear infections, and this may be the only symptom they have.
• Hot spots. Hot spots are often seasonal and affect breeds like German shepherds and golden retrievers more than others. Food allergies are among several potential causes of hot spots.
• Sneezing. While the occasional dog sneeze is normal and even cute, frequent or habitual sneezing may be a sign of a more serious underlying issue like an allergic reaction.
• Skin rashes, scales discoloration, or hair loss. Food allergies can lead to a number of concerning skin conditions in dogs, such as crusty scabs, red or inflamed skin (atopic dermatitis), or hair loss due to self-trauma.
• Red eyes (with or without discharge). Humans in pollen season recognize this symptom as a telltale sign of allergies, and the reddening of eyes in dogs can occur due to allergies as well.
• Diarrhea, vomiting, or gastrointestinal distress. Like our own bodies, dogs’ bodies tend to want to expel unwanted substances, like food allergens. Chronic diarrhea, vomiting, or problems like straining to pass stool may all be signs of a food allergy, and a good reason to visit the vet for answers.

A suspected food allergy is a serious matter for dogs that can adversely affect quality of life. It can be tricky even for professionals to diagnose food allergies, so knowing the proper steps to take is important. Here are steps to follow if you suspect a food allergy in your dog.

1. Identify the allergen

The first step to identifying a food allergy in dogs is to determine if food is in fact the offending allergen. Environmental or seasonal allergies caused by things like mold or dust mites may be the issue instead. Therefore, if your dog has skin issues during a certain season, it’s likely caused by an allergen in the environment. Environmental allergy testing can be done using blood tests, however, there are currently no reliable tests to determine food allergies in dogs.

2. Place your pup on an elimination diet

An elimination food trial is the gold standard test for determining if your dog has a food allergy. In this instance, dogs are placed on a prescription diet, either with a novel protein (one that a pet has never eaten before) or a hydrolyzed protein diet, which means that the protein is so small that your dog’s body cannot recognize it and mount an immune response.

In order to perform a proper elimination trial, your dog must be on this new diet for at least 6-8 weeks. It takes a while for a dog’s body to adjust to a new diet so you must be patient.  Also, your dog can’t eat any other dog food, dog treats (except hypoallergenic), or people food during this time period as these can interfere with the trial. Some flavored heartworm and flea/tick medicines can interfere with a food trial as well, so it’s important to talk to your vet about alternative options if your dog is placed on a food elimination trial.

If your dog’s allergy symptoms resolve during the trial, this suggests that your dog has a food allergy and should remain on the prescription diet long term. If no improvement is seen after a 6-8 week food trial, your dog likely doesn’t have a food allergy and can be transitioned back over to an over-the-counter food again.

Elimination diets must be followed strictly in order to accurately get results. Ideally, diets should consist of a single protein and a single carbohydrate source (e.g. fish and potatoes or rabbit and peas).

👉 Commitment is key, as simply cycling through different foods to find which leads to a reaction is likely to be ineffective or lead to inconclusive results.

Once you and your vet have determined the cause of your dog’s food allergy without any reasonable doubt, the obvious first step is to eliminate the offending food. If you’ve completed an elimination trial, it’s best to keep your pet on that food, especially if the symptoms have subsided. If you try to switch back to an over-the-counter diet, it may trigger your dog’s food allergy symptoms to return.

Unfortunately, diagnosing food allergies in dogs can be a difficult and drawn-out process, and you don’t want to see your dog suffering in the meantime. Thankfully, there are a number of effective ways to treat allergy symptoms in dogs, even from your own home.

• Hypoallergenic dog foods. There are an increasing number of high-quality hypoallergenic dog foods on the market nowadays. These formulas are usually made from novel proteins and simple ingredients, to better cater to canines with food intolerance issues.
• Topical treatments. Certain ingredients like apple cider vinegar, aloe, and colloidal oatmeal have proven soothing properties for canines. You can even make a DIY anti-itch spray at home. You can also find these ingredients in ear wipes and paw balms to target specific areas of the body.
• Skin and coat supplements. In the ever-expanding industry of pet healthcare, many OTC skin and coat supplements now exist, with ingredients like omega-3 fatty acids to address itching and skin conditions in the long term.
• Vet-prescribed medication. In extreme cases of allergy symptoms in dogs, a veterinarian may prescribe a number of safe and effective anti-itch medications. Examples of these include the oral tablet Apoquel or the injectable medicine Cytopoint.