Food allergies vs. food intolerance

These concepts are not one and the same. A good example is lactose intolerance, which is due to a deficiency of lactase, an enzyme used to break down milk sugars. In food intolerance, the common manifestation is diarrhea and vomiting.

An allergy, on the other hand, is an over-reactive response by the body’s immune defenses. When your dog comes into contact with something s/he’s allergic to, her/his immune system goes into overdrive attacking the allergen, which results in skin problems, itching, or hair loss.

Therefore, if your dog is suffering If your dog is suffering from food intolerance rather than a food allergy, then hypoallergenic dog food will not be able to help. We recommend seeing your veterinarian to get the best possible solution for your pet. Food intolerances result from deficiencies in enzymes—nutritional profile differences.

Two approaches in clinical dermatology

  1. Exclusion Diet Principle

These types of foods take special precautions to avoid being cross-contaminated. These include lamb and rice, venison and rice, and rabbit and tapioca. Instead of giving corn and chicken, you may use the above ingredients as replacements. This is usually the first step in ruling out allergies.

  1. Hydrolyzed Feeds

Hypoallergenic dog foods may also be hydrolyzed, meaning that they go through a process of breaking down proteins on a level so small that they can no longer be “seen” by the dog’s immune system body to recognize them as allergens. This is often a prescription dog food, so you will need to talk to your veterinarian about this as an option for your dog. It is a fattening diet ration in that dogs with this level of protein digestibility may precipitate undesired weight gain. Therefore it must be transitioned to another prescription that is not associated with allergies to avert weight gain. This diagnosis maybe verified or supported by Intradermal skin (IDST) testing for specific allergens. In the early phases of the diagnostic procedures, the removal of the suspected food allergies is key to make informed inferences on the most likely allergen.

Reintroduction of the suspected allergen in the diet and inducing the same allergic dermatoses is proof that indeed we have nailed the culprit ingredient.

While some companies sell over-the-counter foods that claim to be good for allergies—and some may contain supplements that can be helpful in controlling environmental allergies—these foods are not ideal for treating food allergies. Allergies can still happen with any and every kind of food ingredient, be it lamb, chicken, beef, fish, rice, wheat, oats, or even tapioca.

Dog food allergies are a tricky business. Fortunately, they’re also the type of allergy your dog is least likely to suffer from. If your dog is showing signs of allergies, talk to your vet before making any changes to his or her food. Even if it turns out that s/he does have a food allergy, changing his or her food without a vet’s supervision could make it more difficult to diagnose.

It is also a common mistake to diagnose or ascribe all dermatoses as allergic reactions.

There is a term apt for all suspected and anecdotal allergies: “over-diagnosis.” Here are three definitions:

  1. The diagnosis of “disease” that will never cause symptoms or death during a patient’s ordinarily expected lifetime.
  2. A side effect of screening for early forms of disease.
  3. The definition I favor most is when a disease is diagnosed correctly, but the diagnosis is irrelevant in that it is not dealt with appropriately and ends up becoming anecdotal as well the stuff that leads nowhere. (


This appeared in Animal Scene magazine’s June 2018 issue.