The diagnosis of Adverse Food Reactions

How easy is it to diagnose AFR in dogs and cats? Are blood tests reliable?

The gold standard procedure for diagnosing AFR in small animals is an elimination diet followed by a challenge phase. Blood tests aren't reliable for AFR diagnosis. The only test with strong negative predictive value in dogs is the patch test, but its application in clinical settings can be challenging.

What are the current best practices for running elimination diet trials?

An elimination trial can be conducted using a highly hydrolyzed diet, a selected protein commercial diet, or a home-cooked diet containing ingredients the animal has never consumed before. This specific diet should be fed for 8 weeks. If there is improvement, the previous diet is then reintroduced as a challenge. According to recent publications, cutaneous reactions may reoccur within a few hours or up to 14 days after reintroduction.

Where do supportive medications (steroids, oxalibs, antibiotics) for the length of trials potentially play a role to assist client compliance?

8 weeks is a long time, especially for animals that show no improvement with a diet change. For this reason, dermatologists have developed a standardized protocol with very low doses of short-term corticosteroids while waiting for the diet change to take effect.

How important is the dietary challenge as part of the trial process? What is the key reason for this?

While dietary changes are the most likely cause of improvement, environmental factors, such as the end of pollen season or weather changes that reduce allergens, can also contribute. That is why to confirm AFR diagnosis, you need to perform a challenge test with the pet’s previous food. 

To learn more, watch the full video!

You could also be interested to watch the following videos:

- Definition and aetiology of canine Adverse Food Reactions

- How to answer common pet owner questions on canine Atopic Dermatitis and Adverse Food Reactions? 

- Long term management of canine Atopic Dermatitis and cutaneous Adverse Food Reactions