Hii @savemejeebus! Welcome! )
You know my oldest Bully Chelios (1yr) the same thing occurred to him when he was about the same age, maybe a month or two older. Well he was on Royal Canin && got horrible hives, swelling it was bad! :/ Vet also gave us antibaotics, gave him a shot, && also benadril. He was on the pills for over a money until we finally figured it might be his food && switched him. To Blue Buffalo we saw amzing results in less then two weeks. After Blue buffalo we went to Avoderm which Chelios LOVED but Faith was getting sick to that so we moved to Fromm Surf & Turf which is AMAZING! They both love it and we havent seen ANY problems since. But honestly, its all up to the dog. What one food maybe good for one could be bad for the other. It's all a process of elimination unfortunatly! :/ Try out different foods until you see && like one that fits your dog!