Are Dogs Allergic to Oats? Signs of Oat Sensitivity

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Oats are an unlikely cause of food allergy in dogs. In a review of the published studies covering 297 food-allergic dogs, the most frequently reported culprits were beef, dairy, chicken, wheat and lamb, and oats did not appear at all. Any food can cause an allergy in an individual dog, so an oat allergy is possible, but it is uncommon. For most dogs, a small amount of plain cooked oats is fine. The bigger risk is flavoured or instant oatmeal, which can contain sugar or the sweetener xylitol, and xylitol is dangerous to dogs.

What causes food allergies in dogs?

A food allergy is the immune system overreacting to part of a food, usually a protein. VCA Animal Hospitals explains that “the most common food allergens in dogs are proteins, especially those from dairy, beef, chicken, chicken eggs, soy, or wheat gluten.” VCA also says allergies tend to develop “after prolonged exposure to one brand, type, or form of food.” In other words, dogs tend to become allergic to what they have eaten for a long time, not to something new.

The best summary of the evidence is a 2016 review in BMC Veterinary Research by Mueller, Olivry and Prélaud. Across 297 dogs with a confirmed food reaction, the reported allergens were:

• Most often: beef (34%), dairy (17%), chicken (15%), wheat (13%) and lamb (5%)
• Less often: soy (6%), corn (4%), egg (4%), pork (2%), fish and rice (2% each)
• Single dogs: barley, rabbit, chocolate, kidney bean and tomato

Oats are not on that list. That does not mean no dog has ever reacted to oats. VCA is clear that “virtually any food ingredient can produce an allergy”. But if your dog is itchy or has a sensitive stomach, the common proteins are the more likely suspects, and an oat-free diet on its own is unlikely to solve the problem.

Signs of a food allergy

VCA lists the usual signs of food allergy in dogs as “itchy skin, paws, or ears or digestive disturbances such as vomiting or diarrhea.” Merck’s guide for dog owners adds that food allergy looks similar to airborne allergy, “except there is little variation in the intensity of itching from one season to another.” None of these signs points to a particular food. They overlap with fleas, environmental allergies and skin infections, which is why a vet needs to look at the whole picture.

Know the emergency signs. VCA’s guidance on hives in dogs warns that facial swelling can spread: “If the swelling progresses to the throat, breathing can be compromised and result in a medical emergency called anaphylaxis.” If your dog’s face, lips or eyes swell, or your dog struggles to breathe, contact a vet or emergency clinic immediately. Do not give human medicines.

How a vet finds out whether oats are the problem

There is no quick test. Merck says that “food allergies are diagnosed by feeding a limited foodstuff (elimination or hydrolyzed) diet and seeing if the itching resolves,” and that “blood and skin tests are not reliable for diagnosis.” A systematic review of the available tests found the same: serum food-antibody tests “showed low repeatability and, in dogs, a highly variable accuracy.” Be cautious of any blood, hair or saliva test that claims to list your dog’s food allergies.

An elimination trial works like this:

• Your vet chooses a diet, either a prescription hydrolysed diet or one made from ingredients your dog has never eaten. VCA notes it “must not contain any ingredients that your dog has eaten in the past.”
• Nothing else is fed. No treats, table scraps, flavoured chews or supplements, which VCA also specifies.
• It lasts at least 8 weeks. An evidence review by Olivry, Mueller and Prélaud (2015) concluded that trials “should last at least 8 weeks” to diagnose more than 90% of affected dogs. VCA describes 8 to 12 weeks.
• Then a challenge. If the signs clear up, the old food is reintroduced. According to VCA, symptoms that return “within one week of a food challenge” confirm a food allergy. Your vet can then reintroduce single ingredients, oats included, one at a time.

This takes patience, but it is the only way to know. Removing oats on a hunch while still feeding beef or chicken treats will not tell you anything.

Why oats appear in so many dog foods

Oats are a common carbohydrate in commercial foods and treats. In the American Kennel Club’s article on oatmeal for dogs, Dr. Carly Fox of the Schwarzman Animal Medical Center calls oatmeal “a great alternative carbohydrate for dogs that may be sensitive to wheat or grains.” The same article notes that oatmeal is high in fibre. It also carries a warning from Dr. Fox: too much fibre “can lead to GI upset, diarrhea, and vomiting.” A little goes a long way.

How to share oats safely

If your vet is happy for your dog to have some, AKC’s guidance comes down to a few rules:

• Plain, minimally processed oats. Dr. Fox advises against instant oatmeal, which she says is highly processed: “The least processed version provides the most health benefits.” Plain old-fashioned rolled oats fit that description, as does any plain rolled or porridge oat sold where you live.
• Cooked, in water. AKC says to cook the oats rather than sprinkle them raw, and to use water, not milk, because many dogs do not digest lactose well.
• Nothing added. No sugar, salt, butter, chocolate, raisins or grapes. AKC lists these as harmful.
• Cooled. Serve at room temperature, because hot oatmeal can burn the mouth.
• Small amounts. Think of it as an occasional extra, not a meal. Ask your vet how much suits your dog’s size and diet.

The real danger: flavoured oatmeal and xylitol

AKC is blunt: “Never feed your dog flavored oatmeal, as it often contains more sugar and may even have artificial sweeteners, such as xylitol, which is toxic to dogs.” The US Food and Drug Administration explains why. In dogs, xylitol can trigger “a rapid and profound decrease in the level of blood sugar (hypoglycemia), an effect that can occur within 10 to 60 minutes,” which “can quickly be life-threatening.” The ASPCA adds that xylitol can also cause “potentially liver damage depending on the amount ingested.”

Sugar-free porridge sachets, oat bars, flapjacks, granola and baked goods can all contain xylitol, so read the label. A pack of plain rolled oats should list just oats. If your dog has eaten something that may contain xylitol, call your vet or a pet poison helpline immediately. Do not wait for signs.

Oats in shampoos and treats

Oats turn up in more places than the food bowl: biscuits, chews and oatmeal-based grooming products. If your vet starts an elimination trial, give them a full list of everything your dog eats and everything you put on your dog, including shampoos. Then they can decide what needs to be paused. Do not start or stop products on your own to “treat” itching. Let your vet guide the plan.

The short version

• Oats are an uncommon cause of food allergy. Beef, dairy, chicken, wheat and lamb are reported far more often.
• Signs of food allergy are itchy skin, paws or ears, or vomiting and diarrhoea, and they are not specific to oats.
• Only a vet-supervised elimination diet of at least 8 weeks, followed by a challenge, can confirm a food allergy. Blood and skin tests cannot.
• If you share oats, keep them plain, cooked in water, cooled and in small amounts.
• Never share flavoured or sugar-free oatmeal. Xylitol is a genuine emergency.

This article is general information, not veterinary advice. If your dog is itchy, unwell or on a special diet, please talk to your vet before changing what they eat.

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