Definition of Food Allergies

Food allergies in domestic dogs involve an abnormal response by the dog’s immune system to something that the dog has eaten. The most common signs of this type of hypersensitivity reaction are intensely itchy skin and gastrointestinal disturbances such as vomiting and diarrhea. More correctly called “dermatologic adverse reaction to food,” this atypical immune system response is among the most frustrating of all common medical conditions for dog owners to deal with. Food allergies can show up in dogs of any age, although most cases seem to occur in young dogs under one year of age. There is no known gender predisposition to developing food allergies. Some reports suggest that certain breeds are at an increased risk, but this remains the subject of much debate in the veterinary community. Diagnosing and treating canine food allergies is possible, but it requires a great deal of time, patience and dedication on the part of the affected dog’s owner in order to be successful.

How Food Allergies Affect Dogs

Dogs that are allergic to some component of their diet will show clinical signs on their skin (redness, itchiness, scratching, sores), within their gastrointestinal tract (vomiting, diarrhea), or both. By far the most common sign of food allergies is intense, non-seasonal itchiness (pruritis), which usually is accompanied by scratching, biting and development of raw, oozing sores. Skin reactions from food allergies tend to show up most frequently on the face, between the toes, on the groin or flank area, behind the front legs (in the armpits) and on the ears. In severe cases, raised red bumps and pustules can develop as well, sometimes referred to as a case of hives. When a food allergy affects the digestive tract, the dog will experience unexplained vomiting and diarrhea and may have more frequent bowel movements than normal.

Causes of Food Allergies

Allergies of any sort, including allergies to ingredients in food, involve an abnormally intense response by the immune system to something that the dog has come in contact with, whether by eating, smelling, touching or otherwise, that tends to show up on the dog’s skin. When a food allergy is suspected, most veterinarians will recommend an elimination diet in order to identify the exact ingredient or ingredients that are causing the allergic reaction. Any ingredient in commercial or even homemade diets can cause allergies. Common food allergens for our companion dogs include beef, dairy products, wheat, eggs, chicken, lamb and soy. It can take months using an elimination diet to identify the particular food product responsible for the dog’s allergies, but the process is worthwhile and almost always successful. The premise of an elimination diet is to only feed specific identifiable ingredients (like boiled rice and chicken) at first, and then to gradually add other ingredients to the diet one at a time, assessing the dog’s reaction, if any, to each ingredient.

Preventing Food Allergies

Once a food allergen is identified, owners will need to manage their dog’s diet to be sure that the particular ingredient is not fed. There are a number of high quality commercial diets that use novel protein sources (such as venison, duck and salmon) and often work well for dogs with allergies to more common components of commercial kibble.