excerpt below from: http://www.2ndchance.info/Apoquel.htm
Food Allergies are probably over-diagnosed in dogs (they account for, perhaps 5-10%). Hypoallergenic diets are occasionally, but not frequently, helpful in canine atopy cases but you should always give them a try. Food intolerances are more common – but considerably more likely to result in digestive disturbances and diarrhea than in itching problems.
I assume you have checked via the search engine here /forums/search/allergies/
My dog was tested for environmental allergies by a dermatologist and has responded well to allergen-specific immunotherapy. We didn’t do the blood test for food allergies. As food sensitivities tend to fluctuate anyway.
I would never consider any mail-in saliva or hair test. Most people complain that their dog tests positive for everything!
The best choice would be to see a board-certified veterinary dermatologist, if one is available near you (here is a list: http://www.acvd.org/).
