Is anyone's dog allergic to Blue Buffalo food? Our 8 month old cardi recently developed a fairly severe skin rash on his rump, near the base of his tail. We took him to the vet this morning, and he thinks it is related to food allergies. About a week ago, before I noticed any rash, we switched him over to Blue Buffalo, the fish and sweet potato kind. I thought Blue Buffalo was supposed to be good for dogs with allergies?! I don't know for sure that it is the Blue Buffalo food, because we have been mixing in his old food which is just Iams puppy food, but the timing seems like that's probably what it is. Has anyone else experienced allergies with this brand?