Here at the clinic, we see A LOT of pets with allergies.
Generally, allergies are divided into two main triggers: Food and Environmental
We start to think about food allergies when we see pets that are itchy, have frequent skin or ear infections, sensitive stomach. Food allergies typically do not have a seasonal pattern.
Dogs are not born with food allergies, rather they become sensitized to certain ingredients over time. Therefore, it is possible for a dog who has been on the same diet for multiple years to develop allergies to the diet. Food allergies can technically be triggered by any ingredient in the diet, but the most allergenic ingredient is protein, mid-size proteins to be exact. They can be meat or plant in origin.
Common allergens for dogs include chicken, beef, dairy and wheat.
Common allergens for cats include beef, dairy, chicken, egg and fish.
Unlike environmental allergies, there are no formal blood or skin tests that can determine that a pet has food allergies, or what part of the diet they are allergic to. The only way to determine if a pet has food allergies is to perform a food trial. Food trials are performed over 8-12 weeks, where we feed ONLY the specific food. This timeline is due to how long it can take for the skin to normalize after the food allergen is removed. If the pet’s skin has improved over that time, we can perform a food challenge, where we feed the food that the pet was on previously and monitor for return of symptoms. Since every pet is different, we may have to try a few different diets before finding the right one!
Now, about the diet. Hypoallergenic diets are divided into two categories: novel ingredient and hydrolyzed.
A novel ingredient diet is a diet that contains ingredients that the pet has likely not been exposed to before. The immune system may tolerate these diets because it hasn’t had time to develop the allergy to that ingredient. It is possible for pets to cross-react to ingredients that are similar, for example a dog that has reacted to beef may also react to venison. Novel protein diets that we have had success with include kangaroo and rabbit.
Hydrolyzed diets contain ingredients that have been hydrolyzed or digested into smaller molecules (smaller than those mid-sized protein molecules). These molecules are thought to be too small to trigger the allergic reaction caused by common triggers. These diets may be a better choice for pets who have previously been exposed to a wide variety of food or treats.
We do recommend veterinary diets for food trials, as some store-bought foods can still contain ingredients that are not listed on the label. Grain-free diets will not be effective in a food trial unless the pet has a known grain allergy.
Food trials require a lot of patience and effort, and can definitely be frustrating at times. However, they can be so rewarding once we have a pet whose itchiness is controlled and is comfortable again!