Petoskey Vet

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Food Allergy

Posted on October 16th, 2014

Food allergy is a common problem in our dog and cat populations. Seventy-five percent of the immune system in dogs and cats is contained in the GI system. Redness and itching of the skin caused by food allergy are very similar to those of atopy(environmental allergy) and are frequently distributed over the same regions of the body. Unlike atopy, food allergy does not start as a seasonal problem and is poorly responsive to steroid therapy. The lack of seasonal presentation and poor steroid response are very helpful in the diagnosis of food allergy. The protein and/or carbohydrate source in the diet are the cause of the immune reaction. Counter to the usual assumption that pets are reacting to a new diet an owner is offering, food allergy develops over time to a long term diet. It is this sustained protein and/or carbohydrate exposure to the GI immune tissue in food allergic animals that causes the sensitivity. Treatment for food allergy in dogs consists offering a diet containing a protein and carbohydrate source never seen by the GI system. All other treats and foods are eliminated from the diet. This diet typically requires a minimum of 6 to 12 weeks to begin reduction of allergy symptoms. If successful, the only way to confirm the diagnosis is to reintroduce the previous diet and see if symptoms return. It is highly recommended that owners limit the variety of protein and carbohydrate sources fed. This is achieved by avoiding diets containing multiple sources of protein and carbohydrate and avoiding frequent diet changes. This way, in the unlikely event an elimination diet is needed, the diet options will be significantly greater.
Here is the silver lining; although it is likely that most dogs with atopy have some level of food allergy due to the large proportion of GI immune tissue , greater than 80% of “combination” allergy patients can have their symptoms managed effectively by addressing their atopy alone. Thus avoiding the need for lifelong elimination diets and treat avoidance.
Food allergy in feline patients is uncommon and is usually related to rodent ingestion. The symptoms usually present as ulceration and swelling of the lips and soft tissues around the mouth. Unlike dogs, food allergy symptoms in cats are often strongly responsive to steroid therapy.