Allergies: Food

What is food allergy?

Food allergy is one of the five most common allergies or hypersensitivities known to affect dogs. Most people know someone who is allergic to certain foods, such as strawberries or nuts. It is only recently that food allergies have become recognized in dogs. The signs are usually itchy skin or an upset stomach. Other more subtle changes can also occur, including hyperactivity, weight loss, lack of energy and even aggression.


What are the signs of food allergy? My dog just seems to itch and occasionally has diarrhea.

Many dogs will occasionally react to something they ate. This may represent sensitivity to a particular type of food, causing a mild gastrointestinal upset rather than a true allergic reaction.

Food allergy is different. Antibodies are produced against some part of the food, usually a protein or carbohydrate. In a pet with food allergy, the immune system overreacts and produces antibodies to substances that it would normally tolerate. This excessive response is termed an allergic or hypersensitivity reaction. Most pets with food allergies show itching rather than vomiting or diarrhea.


Are some ingredients more likely to cause allergies than others?

The most common food allergens in dogs are proteins from dairy products, beef` or gluten (from wheat). Each time a pet eats food containing these substances, the antibodies react with the antigens and symptoms occur.


Are these the only food ingredients likely to cause food hypersensitivity?

No, virtually any ingredient can produce an allergy. Proteins are the most common cause but other substances and additives can also be responsible.


How is the condition diagnosed?

Until recently, feeding an elimination diet was the only means of determining the presence of a food allergy. This is a hypoallergenic diet that contains none of the ingredients that the pet has eaten in the past.  Elimination diets are generally fed for a minimum of eight to twelve weeks.

There are blood tests that may give an indication of whether the dog is allergic to specific foods. These are called serum IgE tests and your veterinarian will discuss whether or not they would be of benefit in diagnosing your pet’s condition.


How is a food allergy treated?

Once the offending food substance has been identified, a diet is chosen that does not contain these particular substances. Today there are a number of commercially available, palatable, hypoallergenic diets that can be fed for the rest of your dog’s life. Your veterinarian can discuss the best choices for your pet, based on the results of testing.

Occasionally commercial diets containing the right constituents are not available. or your pet will not eat them. If this occurs, you may have to prepare a home cooked diet.


Can the problem be cured?

The only cure is avoidance. Some pets will require medication during severe episodes but most pets can be successfully treated with a hypoallergenic diet.


Is it likely that my dog could develop other food allergies?

It is not uncommon for dogs that have developed an allergy to one particular food to develop other food-related allergies. In addition, many dogs with food allergies have other allergies, such as atopy, flea allergy, etc.

If you think your pet may have a food allergy, you should discuss this with your veterinarian, who can help your pet resume a healthier, “itch-free” life!


  This client information sheet is based on material written by Ernest Ward, DVM.

© Copyright 2005 Lifelearn Inc. Used with permission under license. April 21, 2014