Food allergy testing may be required to help your veterinarian determine the cause of your dog’s itchy skin or his upset stomach. Food allergies are the third most common allergy in dogs (after flea allergy and atopy, or inhalant allergy), and they affect about 10 percent of all American dogs.
The Types of Allergy Tests Your Veterinarian May Use
The first step your veterinarian will take in diagnosing a food allergy will likely be to rule out any other cause for your dog’s itchy skin, including flea allergy or mange. He or she will conduct a complete physical on your dog and may conduct other tests to exclude other conditions that resemble food allergies.
What an Exclusion Diet Tells Your Veterinarian
One of the most common tests your veterinarian will use on your dog is an exclusion diet. This special diet will contain new and unique sources of protein and carbohydrates that your dog has never eaten before, such as venison and potato or rabbit and rice. In most cases of food allergy, the dog’s dietary protein source is to blame, but sometimes the carbohydrate source is the cause of the allergic reaction.
Transition your dog onto the new exclusion diet by gradually weaning him off his current diet. Offer a diet that consists of three-quarters old food and one-quarter exclusion diet for a week, then offer a 50-50 mixture of both diets for another week, followed by a week of one-quarter old food and three-quarters exclusion diet before offering the exclusion diet exclusively.
Your dog will eat this special diet and only this special diet for up to 12 weeks in order for your veterinarian to monitor his skin condition and other allergic signs to determine whether or not your dog is improving on the new diet. Your veterinarian will pay special attention to your dog’s skin condition, the presence or absence of secondary skin infection and the condition of your dog’s ears. During the diet test, your dog cannot eat treats, flavored medications, table scraps or even chew on flavored rawhide chews because any of these items can influence the outcome of the exclusion diet test.
Retesting Is Needed to Complete Diagnosis
If your dog remains symptom-free after eating the exclusion diet, your veterinarian will retest for his food allergy by gradually reintroducing ingredients from his original diet to the exclusion diet. When an ingredient triggers an allergic reaction, your veterinarian will have the confirmation he or she needs that your dog has a food allergy.
How to Proceed After a Diagnosis
The easiest way to prevent a food allergy in your dog is to feed him a diet that does not include the allergy-causing ingredient, which means that your dog’s diet will need to be changed permanently. Many owners choose to feed their pets the exclusion diet as the dog’s new regular diet, but remember that your dog can develop an allergy to his new diet over time.