My 9 month old bully has had hives for 4 days now. I've been giving him Benadryl twice a day which calms the swelling but they don't go away. By the morning he is covered again and itching like crazy. About a month ago he had hives for the first time and as a new bulldog owner I rushed him to the vet scared. $250 later they gave him 2 shots, one of which was Benadryl and told me to continue to give it to him for the next 48 hours. They said maybe a spider bite. This time I just can't figure out what it could be and I don't want to rush to the vet for them to tell me the same thing. Nothing has changed in his diet nor has anything changed in his daily routines or around my house. His behavior is the exact same too, happy as anything, hyper, jumping, running etc. Any ideas? Suggestions? I'm worried that it's lasting this long.