This article is from the Canine Allergies FAQ, by Cheryl Minnier with numerous contributions by others.
Dogs are not allergic to a dog food per se, rather they react to one
or more of the ingredients in the food. Some of the most common
culprits are beef, pork, chicken, milk, whey, eggs, fish, corn, soy,
wheat and preservatives. Many animals are now developing allergies to
lamb as well. This was once thought to be very hypo-allergenic, but
the more it is used, the more sensitivities are springing up.
The first step in diagnosing a food allergy is to eliminate all
possible allergens and feed ONLY a homemade diet with ingredients the
dog has never eaten before. The diet should be a protein and a starch.
Good examples are one part lamb, rabbit or venison mixed with two
parts rice or potatoes. NOTHING else can be fed during this time; no
biscuits, chewable heartworm pills, chew toys or any table scraps!!
You must also keep the dog away from feces if he or she is prone to
This diet should only to be fed for a short period, while testing for
allergies. It is not nutritionally complete enough for long term use.
Check with your veterinarian before beginning the test. If the
symptoms improve during the trial diet, go back to the original food
for several days. If symptoms reoccur you know that something in the
food is causing the reaction. The next step is to return to the trial
diet and add one new ingredient a week (i.e. add beef for one week and
if no symptoms occur add corn the next week for one week).
Once you have discovered the allergen you can look for a commercial
food which does not contain that ingredient. According to Dr.
Ackerman, approximately 80% of dogs with food allergies can be
maintained on a commercial hypo-allergenic diet. Some of the common
hypoallergenic diets include "Nature's Recipe", "Sensible Choice" and
"Natural Life". "Nature's Recipe" makes a lamb and rice food, a
venison and rice diet and a vegetarian diet, none contain chemical
preservatives. "Natural Life" also makes a preservative free, lamb and
rice food called Lamaderm. "Sensible Choice" is a third brand that is
considered hypoallergenic because it contains neither wheat or corn
and comes in a lamb and rice formulation.
Note: just because a food is labeled "Lamb and Rice" do not assume it
is hypoallergenic. Many contain wheat, corn, soy, beef or
preservatives. This process of elimination is trying and time
consuming. You should be aware that it may take up to 10 weeks to see
an improvement. However, it is the best method available to test for
food allergies. You may wish to try switching your dog to one of the
foods listed above for a month as a trial. If the dog shows
improvement you know you are dealing with a food sensitivity, you just
won't know which ingredient to avoid. If there is no improvement, you
will need to begin the elimination testing.