Introduction
Food allergies are an abnormal response to an ingested product that produces clinical signs, most commonly pruritus (itchiness), affecting the skin. More correctly called “dermatologic adverse reaction to food,” this immune system response is among the most frustrating of medical conditions for dog owners to deal with. It can show up in dogs of any age, although most cases seem to occur in dogs less than one year of age. There is no gender predisposition to developing food allergies. Some reports suggest that certain breeds are at an increased risk. Food allergies can be diagnosed and treated, but this requires time, patience and a great deal of commitment by owners.
Symptoms of Food Allergies in Dogs
Dogs that are allergic to some component of their diet will show clinical signs on their skin (redness, itchiness, scratching, sores), in their gastrointestinal tract (vomiting, diarrhea), or both. Far and away the most common sign of food allergies is intense, non-seasonal pruritus (itchiness), with the accompanying scratching and biting at the pruritic sites. The most common places for skin reactions from food allergies to occur are on the face, between the toes, on the groin or flank area, behind the front legs and on the ears. In severe cases, red bumps and liquid-filled pustules can develop as well. When a food allergy affects the digestive tract, the dog may experience unexplained vomiting and diarrhea, and possibly more frequent bowel movements than usual.
Determining the Cause of a Food Allergy in Dogs
When a food allergy is suspected, the veterinarian will recommend an elimination diet in order to identify the exact cause of the allergic reactions. Any ingredient in commercial or even homemade dog diets can cause allergies. Common food allergens in 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. While your veterinarian can explain the process to you in greater detail, the premise of an elimination diet is to feed only particular, identifiable ingredients (like boiled rice and chicken only) at first, and then add in other ingredients one at a time, assessing the dog’s reaction if any to each new ingredient.
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 available that use novel protein sources (such as venison, duck, salmon) and often work well for dogs with allergies to more common components of commercial kibble.