Update on Food Allergy in the Dog and Cat
Stephen White United States
The elimination diet generally contains one protein and one starch. These must be based on previous exposure of the dog to various foodstuffs. Important to remember is that dogs who live in households with cats tend to have been exposed to fish, through their consumption of either cat food or cat feces. At UC Davis, we often start dogs with pork and potatoes, although pinto beans and potatoes may also be used. Based on non-exposure, rabbit, duck, and tuna are also options. We have also used ‘exotic’ foods like elk when feasible. Other than fresh water, nothing else should be fed to the dog during the elimination diet trial. This means that vitamins and chewing toys must be eliminated, and that flavored medications (such as certain ecto/endoparasite preventatives) should be replaced by other, equally effective non-flavored preparations. Protein-flavored toothpaste should be replaced by the malt-flavored variety. Because the elimination diet is not a balanced one, owners should be warned that the dog might lose weight, develop a “dull” haircoat or scaling, or be hungrier than usual. In cats, we will use lamb-based baby food for human infants.
Certainly, some owners are unable or unwilling to cook for their pet for the period necessary. In such cases, the dermatology service at UC Davis uses commercially available limited-antigen diets. ... Use of a commercially prepared diet will give an approximately 90% chance of determining a food allergy; however, none of these diets will work for all animals, and failure of an animal to improve on such a diet may warrant trying another one, or a home-cooked diet in another trial.
The length of the elimination diet is somewhat controversial, however, our observations have justified a dietary trial of eight to 12 weeks.
Upon resolution of clinical signs with the feeding of an elimination diet, the animal should be challenged with its regular diet to confirm the diagnosis of a food allergy. Recurrence of clinical signs is usually noted within one week, but may take as long as two weeks. At that point the animal is given its elimination diet again, and the owner may then elect to challenge with suspected allergens, each allergen being given one to two weeks at a time. The most common proven allergens in the dog are beef, chicken, milk, eggs, corn, wheat, and soy;
in the cat, fish and milk products. Allergies to more than two allergens are uncommon.