Allergies are so common in Bullies. I think it would be impossible to breed them out of the line, but I might be wrong. We have some breeders on the site that may know more.
Our Bully growing up was allergic to grass. His time outside was very limited and he got steroid shots monthly (they don't usually do that often anymore) The vet kept saying it would shorten his life span, but my mom wanted him to be happy and comfortable. He actually lived to be 12 and it wasn't the shots that did it.