What an ordeal, your poor pup. Here are my thoughts. My allergic dog is no longer scratching. Van-P did work but it's a steroid, I switched to Atopica a lessor evil, it did work too. Then he got sick, we went raw and to a holistic integrative Vet when traditional meds did not help month and a half long diarrhoea. The new VEt had us feed a home cooked diet of one novel protein and one novel carb, for us those were turkey and sweet potato. She also gave him TCM and acupuncture, he recovered AND he stopped itching. We had stopped all other meds. Then we went raw at her urging, still no itching. REal raw, nothing pre-packaged, BARF.
Then he got sick again, diagnosed with Lymphangiectasia, INtermal Specialist Vet got him over that, blood levels recovered but now he is on a special Kangaroo kibble for his gut issues but it is also an allergy food and this is summer three of no more itching. It's
http://www.raynecanada.ca/wp-content...Kang_Oct14.pdf
My boy's allergies were seasonal environmental but I did the Nutriscan saliva test on him and, as is typical, he is now allergic to some foods as well. My information from Dr. Jean Dodds is that your dog is allergic to an allergen whether it's in kibble or raw but raw has far fewer antigen sites so it may take more time for the reaction to build up but chances are if your dog is allergic to chicken in kibble she will eventually react to raw chicken as well.
There is growing acceptance that allergies, some at least, stem from gut issues. This certainly seems to be the case with my dog. Unfortunately it's hard to see gut issues unless, like my poor boy, you have some sign like his horrible diarrhoea. Bloodwork might help, my boy had low albumin counts from the first time I tested him at age 5 (which I did because of the strong meds he was on) but he showed none of the usual symptoms that might signify a reason for it. Now, with a recovery of his gut issue his albumin levels are normal but it was a hard time getting there.
Good luck. What works for one dog may not for another. IN a sense we were lucky, we had that extreme illness and after one failed attempt we got good results right away with remedies we tried.