Allergies

My poor baby Tucker has such bad allergies, basically since he was born. And it's just so hard to pin point what it is. We did a food trial for 3 months and he seemed to do ok and then 2 weeks ago his ears flared up and got super red and he got a rash on his belly and all he could do was itch. So I gave him benadryl (instead of dragging him back to the vet and them saying the same thing and spending an arm and a leg). Well it got so bad he had itched so much this morning his poor ears were bleeding, so I called a veta nd took him in. Maybe it's seasonal allergies and after we have a frost it will go away. But it never does. So he was given prednizone for 3 weeks. I just hope after those 3 weeks he's better. I'm kind of at my wits end and don't know what else to do. :(