Food Allergies and Intolerances: Part 1

Most of us know people who have to be careful about what they eat.

A friend’s son doesn’t tolerate cow’s milk at all while a co-worker can’t be anywhere near a peanut and carries an epi-pen all the time to combat anaphylaxis that might occur if she’s exposed to peanuts or peanut butter. Unfortunately, dogs can have problems with some foods, just as people do, and their reactions can also be just as scary.

What is a Food Allergy?

Food allergies are immune system responses triggered by certain foods. The response may be mild (itching, a rash or sneezing) or can be life-threatening (swelling of the airway), up to and including anaphylaxis. The itching can occur on the face, ears, front legs, paws and around the anus. Chronic ear infections, hair loss due to chewing and skin infections are also common.

A dog suffering from a food allergy that causes anaphylaxis may have trouble breathing (wheezing and straining to breathe), a swollen throat, a rapid pulse, dizziness and loss of balance, a loss of consciousness, a severe drop in blood pressure and shock. Immediate emergency care is vital if the dog is to survive.

Food allergies account for 15 to 20 percent of all canine allergies and are the third most common allergy after inhalant allergies and flea bite allergies. Dogs usually don’t begin showing food allergies until five or six months of age, and reactions can continue throughout the dog’s life. Males, females, neutered and spayed dogs can all develop food allergies.

There does tend to be a genetic component in a particular dog developing food allergies, with some breeds (or some families of dogs within those breeds) more affected than others. West Highland White Terriers, Cocker Spaniels, Rat Terriers and German Shepherds are the breeds many veterinarians reported seeing the most often for this issue. However, any dog, purebred or mixed, can develop food allergies.

What is a Food Intolerance?

A food intolerance is a digestive system reaction to food. Food intolerances are actually more common than food allergies and are often mislabeled as allergies.

Another difference is the length of time before a reaction begins; the symptoms of an allergic reaction tend to appear rapidly (sometimes within minutes) after exposure to a food. An intolerance reaction may not appear for several hours since the food needs to work its way down into the digestive tract.

Symptoms often include abdominal cramps, obvious discomfort, bloating, vomiting and diarrhea. Some or all of these symptoms may be present.



What Foods Can Trigger a Reaction?

The most common foods that trigger allergic reactions include beef, dairy products from cows, chicken, chicken eggs, corn, wheat and soy.  These foods are all commonly found in many dog foods and this isn’t a coincidence; most allergic reactions are often associated with repeated exposure. Some dogs are so sensitive to certain foods that even if a food is used as a part of a recipe in another food, eggs for example in baked goods, and you share a bite with your dog, there can be a reaction.

The foods that trigger a food intolerance reaction can be the same as those that cause allergic reactions although sometimes grains (rice, wheat, corn, barley, and other cereal grains) pose a bigger problem than do meats. Lactose intolerances are not uncommon, especially in adult dogs. These dogs will develop bloating, flatulence and diarrhea a few hours after milk or cheeses from cow’s milk. Dogs may also be intolerant to ingredients or additives rather than an entire food. Food colorings, for example, artificial flavorings and preservatives can trigger reactions.

How is a Food Allergy or Intolerance Diagnosed?

Several health issues can share some of the same symptoms that a food allergy has. A bee sting, for example, can cause swelling and trouble breathing as can inhalant allergies. Your veterinarian will want to identify and treat any health issues prior to dealing with a food allergy issue. This will include any ear infections, skin problems, intestinal parasites and flea bite dermatitis. Once these and other problems are taken care of, then any remaining symptoms can be addressed and determined as to whether there is a food allergy or not.

A similar protocol is followed with any food intolerances. Any digestive issues, including parasites, giardia or other digestive issues need to be identified and treated.

The only certain way to test for food allergies and intolerances is to do an elimination diet and a challenge. The dog is no longer fed any food or ingredient he’s had previously and is fed only unique new foods (like venison and quinoa).  When he’s been fed that and his health is cleared up, with no new allergic or intolerance outbreaks, then one old food is added at a time and is fed for a period of time. If he reacts (depending on how he reacts) there is either an allergy or an intolerance.

In Part 2 of this article, we’ll go into more detail as to how to do an elimination diet, how to watch for a reaction and then how to feed your dog for the rest of his life.

Meet the Author: Liz Palika

Liz Palika is a Certified Dog Trainer, Certified Animal Behavior Consultant, and the co-owner of Kindred Spirits Dog Training in Vista, CA. Liz is also an award-winning author and writer specializing in pets. She writes about cats, cat behavior and health, dogs, dog behavior and health, living with pets, and pet nutrition. Liz’s works have been recognized with many awards, but her most recent book, “Idiot’s Guides: Dog Training” (Penguin Books, 2014) recently won the Best Nonfiction book category in the San Diego Book Writing competition. Liz shares her home with two dogs; Bashir, an Australian Shepherd, and Bones, an English Shepherd. Three cats, Spock, Scottie, and Kirk, provide motivation for her articles about cats. And yes, she is a Star Trek fan. For more information go to

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