Whenever I work with a dog who suffers from chronic ear and anal gland infections, I worry about a food allergy. My dermatology professor called it, “Ears and rears.” When I see a patient with ear problems and impacted anal glands, especially in younger dogs, food allergy goes to the top of my rule out list. I recommend a 12 week food trial with a novel antigen or hypoallergenic diet. If using the novel antigen approach, make sure both the protein and carbohydrate source are new to the dog.
During the trial, the patient cannot eat anything but the test food. One treat can ruin the entire trial! Here are some of the common ways that food trials are ruined;
1) Treats – All treats are forbidden during the trial. All family members and neighbors must be on board with the trial. No sneaking allowed. This includes treats through the backyard fence.
2) Medications – Heartguard may not be given during a food trial nor can other flavored medications.
3) Free roaming – It is impossible to conduct a food trial on a dog who goes outside unattended.
4) Cat food, vomit or feces – During a food trial, the dog must be kept away from cat food, hair balls and the litter box.
After the trial is over, I like to introduce the original food again and see if the signs return.