Food allergy or intolerance?

There is a distinction that needs to be made between food allergies and food intolerances. Food allergies are true allergies and show the characteristic symptoms of itching and skin problems associated with canine and feline allergies. Food intolerances can result in diarrhea or vomiting and do not create a typical allergic response. Food intolerances in pets would be similar to people who get diarrhea or an upset stomach from eating spicy or fried foods. Fortunately, both food intolerances and allergies can be eliminated with a diet free from offending agents.

Common food culprits

Several studies have shown that some ingredients are more likely to cause food allergies than others. In order of the most common offenders in dogs are beef, dairy products, chicken, lamb, fish, chicken eggs, corn, wheat, and soy. As you may have noticed, the most common offenders are the most common ingredients in dog foods. This correlation is not a coincidence. While some proteins might be slightly more antigenic than others, many proteins are similar in form and the incidence of allergic reactions are probably associated with the amount of exposure.


The symptoms of food allergies are similar to those of most allergies seen in dogs and cats. The primary symptom is itchy skin affecting primarily the face, feet, ears, forelegs, armpits and the area around the anus. Symptoms may also include chronic or recurrent ear infections, hair loss, excessive scratching, hot spots, and skin infections that respond to antibiotics but reoccur after antibiotics are discontinued. There is evidence that dogs with food allergies may sometimes have an increased incidence of bowel movements. One study showed that non-allergic dogs have around 1.5 bowel movements per day where some dogs with food allergies may have 3 or more per day.

It is difficult to distinguish an animal suffering from food  allergies based on physical signs. However, there are a few signs that increase the suspicion that food allergies may be present. One of these, is a dog with recurrent ear problems, particularly yeast infections. Another, is a very young dog with moderate or severe skin problems. A third tip off, is if a dog suffers from allergies year-round or if the symptoms begin in the winter. And the final clue, is a dog that has very itchy skin but does not respond to steroid treatment.


The diagnosis for food allergies is very straightforward. But due to the fact that many other problems can cause similar symptoms and that many times animals are suffering from more problems than just food allergies, it is very important that all other problems are properly identified and treated by your vet prior to undergoing diagnosis for food allergies, flea bite allergies, intestinal parasite hypersensitivities, mange and yeast or bacterial infections can all cause similar symptoms as food allergies. Once all other causes have been ruled out or treated, then it is time to perform a food trial.

What is a food allergy?

A food allergy occurs when a dog’s immune system mistakenly identifies a particular food ingredient as harmful. And then creates defensive antibodies to fight the invading enemy (the food).

What are the signs and symptoms of a food allergy?

The symptoms of an allergy include skin rash, hives, itching, paw biting, obsessive licking and sometimes nausea or vomiting.

What is a food intolerance?

A food intolerance is a digestive problem rather than an immune response. An intolerance occurs when a dog’s digestive system is unable to digest a specific ingredient.

If my dog is allergic to a specific dog food, does that mean there’s something wrong with the quality of the product?

Allergies are related to your pet’s own immune system and are not due to a problem with the product itself. So, if a dog is allergic to a particular ingredient, he will likely experience the same unfavorable reaction to that ingredient… no matter what brand you find it in.

If my dog shows signs of an allergy, should I immediately suspect it’s caused by the food?

Maybe not. Because food is only the third leading cause of canine allergies, the signs and symptoms you observe may not even be related to your pet’s diet in the first place.

What are the most common causes of dog food allergies?

Dog food ingredients most likely to provoke an allergic reaction1 include…

  • Beef
  • Dairy
  • Chicken
  • Lamb
  • Fish
  • Corn
  • Wheat
  • Soy
  • Yeast

What else could cause my dog to be allergic to his food?

Many times, it’s not even the ingredients themselves that are the problem. In some cases, a dog can also be allergic to contaminants in the food itself.

What should I feed my dog if I suspect his allergy symptoms are caused by his food?

Since certain recipes have been intentionally designed to help you control or isolate these problems, you may want to speak with your vet first then look into foods that are grain free, no soy, no corn, gluten etc. speak with your vet about food recommendations or a distributer of raw feeding this may be a great option as well.

What should I do if I believe my dog might have allergies?

Allergies can have serious consequences for your pet. Remember, much of the advice offered by well-meaning dog owners throughout this site may not be appropriate for your dog. So, be sure to consult a qualified veterinary professional for help.