you may have to try the Hills perscription diet you don't have to get it from the vets as you can bulk order on line. Maybe try a tin or 2 from the vet yes I know it's dear but if it does the trick it will be cheaper than all the anti bs and jabs. I had to put my dog on this diet as I had tried everything else he seems to be allergic to some proteins. So far he has been fine.