My Silky Tobey was having real skin allegeries he would bite himself so bad that his hair on his back was going bald and his skin so dry. My vet gave him antibiotics and that help but once he was off it stop working. So then they gave him a steriod shot that helped but I also changed his food to Wellness Super5mix and have my Izzie(yorkie) on the puppy formula, I also use an oatmeal shampoo. Its been about a month and Tobey has been doing so well no itchiness or biting himself at all and Izzie is doing great on it too.
I also want to say thank god for this site, I would have kept him on the old brand of food, I never thought it was related food. My vet never mention it, that's why I had to switch and find a new vet.