Food Allergy trials in dogs


A food allergy is a reaction to food involving the dog’s immune system. A protein particle in the food usually causes the reaction. Typical signs can include itching, licking, chewing paws, etc.

In some cases the dogs may only show chronic otitis. Gastrointestinal signs such as vomiting, diarrhea, belching, and frequent bowel movements are also possible. Persisting gastrointestinal and skin signs can both be present as well.

We will need a complete medical history. The most important information you will need to provide is a thorough history of what foods and treats your dog has eaten. This includes table scraps and chew toys with food flavorings.

The new diet will contain a “novel” (new) protein and carbohydrate source.

Commercial diets are not appropriate. They may claim to be “hypoallergenic” or “good for sensitive skin”, but these claims have no official meaning because the pet food companies do not have to list every ingredient on the label.


Trial food categories

Prescription Diets

These are made to specifically and always contain the same ingredients. The protein source and carbohydrate sources never change in these food allergy diets and are only available through veterinarians. They are formulated to treat a medical condition, in this case, food allergies.

Hill’s Prescription Diets:

  • D/D canned/dry­ salmon & potato/rice
  • D/D canned/dry­ duck & potato/rice
  • D/D canned/dry­ venison &potato/rice
  • D/D dry– egg & rice
  • D/D canned­ lamb & rice

Royal Canin Diets:

  • Ultamino
  • Selected Protein Adult KO

Low Antigen Diets

The protein(s) in a diet that can be responsible for food allergy signs are called antigens. Low antigen diets are also prescription diets. In these diets, the protein has been formulated (hydrolyzed) to be so small that it will not stimulate the immune system. The diet may also have used small carbohydrates as well to avoid the potential immune response to proteins in the carbohydrate component of the diet.

Royal Canin Prescription Low­Antigen Diets:

  • Hydrolyzed Protein HP

Hill’s Low Antigen Prescription Diets:

  • Z/D Ultra Allergen Free dry and canned­hydrolyzed chicken and refined starch
  • Z/D Low Antigen –dry and canned­hydrolyzed chicken and single source carbohydrate (potato)

Home Made Diets

If your pet will not eat any of the prescription diets or low antigen diets or has a concurrent medical issue that prevents the use of these diets, a homemade diet may need to be used.

A homemade diet recommended for your dog can not be fed long term, as it is not a complete and balanced diet and as such deficient in important nutrients. It initially contains only two ingredients: a protein source and a carbohydrate source. Some of the protein and carbohydrate sources a veterinary nutritionist may select from include:

Protein Source Carbohydrate Source

  • Tuna Yams
  • Salmon Sweet potatoes
  • Pinto Beans Pumpkin
  • Rabbit Oats
  • Game Meats Barley
  • Garbanzo (chickpeas) Quinoa



The only way the food trial will be successful is by feeding only the prescribed diet for the required period of time. Feeding your dog any type of snack or chew toy with food flavoring can affect the length and success of the food trial. Everybody must realize the importance of this.

  • Visitors, relatives, delivery men, children
  • Inform visitors, relatives, delivery men and children that the dog cannot be given any other foods.
  • If using a dry diet use pieces of the dry kibble as a treat or put it in a Kong for entertainment and chewing.
  • If a canned diet is fed, you can make slices and bake them into dry snacks.
  • When you expect visitors crate the dog or put the dog in a place with no access to them.
  • Give the relatives/friends/visitors etc. only acceptable treats. Again: everybody must be a part of the effort to complete the food allergy trial.

Multiple pet household

You must prevent the dog from eating another dog’s cat’s or other pet’s food.

  • Separate the animals when they are fed.
  • Remember any feces will need to be picked up immediately. Even a small lick of an inappropriate food can potentially be a pitfall in a food allergy trial.
  • If possible, put all the dogs on the new diet.
  • Put the cat food up out of the dog’s reach. Place the cat food in a room a small enough entrance that only the cat can gain access to the food.
  • Avoid or stop free feeding all pets in the household so inappropriate food access in controlled.


Be sure to let us know if your dog is taking any medications that we are not aware of. This includes: chewable heartworm pills, flavored antibiotics or anti-inflammatories, flavored vitamin mineral supplements, joint supplements or coat supplements. These all need to be replaced by an acceptable unflavored pill, topical or possibly an injection. Be sure to ask your veterinarian before giving any supplements or medications during a food allergy trial.

If your dog is treated at an emergency clinic where the veterinarian is not familiar with your dog’s history, be sure to inform them that the dog is currently on a strict food allergy trial


  • Make sure your dog is confined and cannot wander, as he could get the garbage, compost piles or a neighbor may feed him treats.
  • Keep your dog inside.
  • Be sure your own garbage is not within the dog’s reach
  • Patience and persistence
  • Schedule recheck exams or contact us with progress reports
  • Take photographs before you start the trial and then bi-weekly to monitor the progress.
  • Keep a diary if your dog also has gastrointestinal reactions to food.
  • Be patient: a food trial can take 12 to 16 weeks


Blood test for food allergies

Currently, these tests are not accurate and are not reliable and cannot help to select an appropriate diet for your dog.


After the trial

If you chose the prescription or low antigen diet you have the option of continuing it. If you chose the homemade diet you will have to add nutrition to make it complete and balanced. After that, it can be continued as well.

If you prefer to try and find an “over-the-counter” dog food rather than the prescription or homemade food trial diet, you add a new ingredient individually at a time to the successful diet and monitor the dog’s response. If there is no return of the original skin or gastrointestinal signs, the dog is not allergic to that ingredient.