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Dr. Andy
Dr. Andy, Medical Director
Category: Dog Veterinary
Satisfied Customers: 29958
Experience:  UC Davis graduate, emphasis in dermatology, internal medicine, pain management
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My dog is currently on a hypoallergenic Rx food (venison/potato)

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My dog is currently on a hypoallergenic Rx food (venison/potato) for about 1.5yrs now. I was researching OTC foods and I was looking to switch her to a gluten/grain free salmon/potato & berries food. How long can it take for her to show symptoms if she can't tolerate this food?
Welcome! My name isXXXXX am a UC Davis graduate, and currently, a Medical Director of a veterinary hospital.

I am sorry to hear about this concern about the allergies.
First, if she is doing good, I would be really hesitant to make any changes.
The ol sayin: "if it ain't broke, don't fix it"

But, if you really want to change, symptoms can manifest anywhere from 1 day to a few weeks on the new food.

Also, most over the counter foods are not suitable limited ingredient diets. Why?
Well, the main protein may say fish. But, if there is any other type of protein in there, like some chicken meal, beef meal, etc..that ruins the diet.
Also, most OTC foods are not processed in "clean" facilities. Meaning, a lot of testing has been done on these OTC foods and they find other proteins in the food all of the time.
Just thought you would be curious about that extra information.

But, the symptoms can manifest quite quickly, but not always.

Please let me know if there is anything I did not cover for you. I hope that information has been helpful.
Please remember to select Reply to Expert, if for any reason you need further clarification, have more questions, or were expecting a different type of answer. DO NOT rate yet if have any other questions. My goal is to try and provide you the best answer possible.
Dr. Andy

Customer: replied 3 years ago.

That information is helpful. I just want to clarify though. I read through all the ingredients and the only protein source listed is salmon and salmon meal. So, even though this is the only protein listed in the ingredients, the food could still have traces of other types of proteins present?

I could not have said it better myself.
Excellent interpretation.
Yes, it is very possible that there could still be trace proteins, and for dogs with food allergies, that can sometimes be enough to cause problems.

That is why most vets are fairly adamant to avoid OTC foods when doing food allergy diet trials.

They stick with limited ingredient prescription foods like Science Diet D/D formulas or a hydrolyzed prescription diet.

Dr. Andy
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