Dog Food Allergies 101

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Dog Food Allergies 101


Food adverse reactions may be immunologic (food allergies – hypersensitivity reaction) or nonimmunologic (e.g. food intolerance, toxic food reactions).

They can induce cutaneous and/or gastrointestinal clinical signs (vomit and diarrhea).

Food intolerance is an organic response that can be caused by proteins, food additives, toxins or bacterial contamination.

It is the most common adverse reaction to food in dogs.

Food allergy accounts for approximately 31% of non-seasonal dog dermatitis cases.

It is a common cause of cutaneous and chronic gastrointestinal signs.

It results from an immunological reaction to specific glycoprotein molecules produced during digestion.

Clinical signs occur in dogs as young as four months, up to 12 years of age.

However, 50% of food-allergic dogs are younger than one year of age when diagnosed.

dog food allergies

Generalized pruritus is the more frequent feature of food allergies, in some cases with a preference for the feet and inguinal area.

Here are other symptoms of dog food allergies:

  • recurrent bilateral otitis externa
  • hot spots
  • face rubbing, hair loss
  • pyoderma
Vomiting and diarrhea may also be present.

What is a food allergen?

Food allergens are almost exclusively protein molecules.

All dietary proteins have the potential to induce an allergic reaction because they are recognized as foreign by the immune system.

The size and structure of dietary proteins influence their ability to induce a hypersensitivity.

Frequent food allergens are proteins with molecular weight of 18,000 to 36,000 daltons.

The most common allergens recognized in spontaneously food allergic dogs may diverge according to geographical location.

Some examples of protein sources that commonly induce food allergies are:

  • chicken
  • beef
  • soy
  • egg
Other possible dietary allergens include:
  • dairy products
  • preservatives
  • poultry
  • lamb
  • fish
  • wheat
  • corn
  • rice

Pathophysiology of Food Allergies

The pathogenesis of food allergies is intricate.

It embraces the following mechanisms:

  • permeable intestinal mucosal barrier
  • atypical antigen presentation to the immune system
  • deregulation of the immune system
  • loss of oral tolerance
It is suspected that type IV hypersensitivity or local type I hypersensitivity may be at the basis of canine dietary hypersensitivity.

A dog’s gastrointestinal tract is exposed to considerable amount of potential allergens.

But a small percentage of the canine population presents food allergies.

So, the gastrointestinal system has evolved to provide defense mechanisms against to potential harmful immune responses to food.

Digestion of protein represents the most effective preventive process.

In the gastrointestinal system the majority of food allergens are inactivated during the digestive process.

Nevertheless, some food proteins persist immunologically active and gain access to the circulatory system.

For food allergy to develop, food allergens must rupture the intestinal barrier in order to be visible to the local immune system (GALT).

Allergic sensitization to ingested food allergens occurs in the GALT, where allergen-specific IgE fixes to high affinity IgE receptors on the surface of other immunologic cells (mast cells and basophils).

Succeeding exposure to the same food, cross-linking of antibody-primed IgE receptors leads to mast cell degranulation, discharge of inflammatory mediators and beginning of clinical symptoms.

Related articles:

  1. Dog with skin allergies
  2. No grain dog food

About the Author:

Hi! I'm Dora Mancha, DVM. I am graduated for the Veterinary Medicine Faculty of Lisbon (2009). My degree is recognized by the American Veterinary Medical Association (AVMA). I completed my degree in Veterinary Medicine in July, 2009. Over the first years as a veterinarian my work was closely related to the animal health field. I have gained some average experience having worked in Barcelona University (UAB) Equine Hospital and by working with veterinarians in Portugal. In addition, in 2009 - 2010 I was in Madrid at the University Alfonso X el Sábio doing an internship in the equine service. I am also very interested in small animal medicine and surgery. In fact I worked in several small animals clinics in Portugal improving my knowledge about small animal behavior and health. Dogs always have been present in my life, since I was a child. At the present moment I have four dogs a Labrador, a Epagnheul Breton, a Whippet and a mixed breed dog.

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Why was the Dog Food Selector created?

Each dog has unique needs... The approach "one food for all dogs" isn't the more suitable. Dogs have different sizes, different life stages, unique breed characteristics, health conditions and a few other factors... Choosing the right food for your dog may help him or her life a longer and healthier life! We exist to make that task easier for you.

How does the Dog Food Selector work?

It's quite simple... It's a 1-2 step process. You just have to fill in the form with your dog's characteristics, like gender, age, size, activity, health conditions and a few other important data and click "search". Then, you'll see a list of dog foods with the highest review score. If you wish you can see all the detailed review of each individual dog food.