VN June 2021

Vetnews | June 2021 31 Using novel protein diets is one way of performing a food elimination trial but we are not always sure of what proteins are considered novel in certain dogs and cats these days. Top 3 allergenic protein sources in adverse food reactions Protein hydrolysate-based diets have been reported to be effective and well tolerated when used as elimination diets for diagnosis of AFR (adverse food reactions) in cats and dogs. A food elimination trial should be performed for at least 6-8 weeks for optimal results. It is advised to slowly transition these animals onto their new diet over 5-7 days to avoid any intolerance in palatability and digestibility (especially when using a novel protein diet). Full understanding of the process by the owner and the entire family is crucial in getting the best results as any deviation in feeding with treats, toothpaste, flavoured medications and even licking the dishwasher can impact on the outcome. Washing hands prior to feeding and feeding in stainless steel bowls are important tips to share with owners. Plastic is porous so keeping the food in the original packaging and not decanting it into a plastic container is best (the same goes for plastic measuring cups). Remind the owner to save a portion of their pets current diet for the later dietary challenge. Setting up appointments for regular follow ups can help the pet owner remain motivated as they often do not see improvements on a daily basis where you as the veterinarian will. Photographs can be a great way to remind yourself of the patient and the progress they are or are not making, and to share this with the owner. Diagnostics always come at a cost and diagnosing a food allergy is no exception. If you suspect a broken bone you would take an x-ray to confirm and if you suspect a food allergy, then an elimination trial is the diagnostic tool of choice. Explaining this to an owner is often the best way to get full commitment by them to the process. If you know the food elimination trial has been done correctly then after 8 weeks you should have noticed one of the following: • Major improvement in the animal • A partial improvement in the animal • No improvement If no improvement is noticed, then atopy is very likely and medical management on top of an atopic diet should be considered. In both cases of where a major or partial improvement is seen it is very important to perform a dietary re-challenge of their original diet. It is crucial to explain this to the owners right from the beginning that this needs to be done to confirm the diagnosis as many owners are reluctant to move back to the previous food, fearing flare ups and decrease in quality of life. The reintroduction of the previous diet should be done progressively, e.g. start with 10-20% of original diet and the rest on elimination diet, then increase this slowly. Clinical signs will usually recur within just a few days, but in rarer cases it can take up to 2 weeks, especially in cats. As soon as clinical signs recur you can stop the original diet and continue with the elimination diet as you have confirmed the diagnosis. Remember atopy and AFR can occur simultaneously which may be the case if only partial improvement is seen in an animal. Unfortunately, like most skin diseases it is a question of management and treatment will be life long, again getting owners to understand this will go a long way in ensuring compliance and a happier pet and owner. Tips on performing a food elimination trial for best results Dr Debby Bain A food elimination trial is the only reliable way to confirm a suspected food allergy but it comes with its own set of challenges.