How long can a dog with lupus survive?

My 10-year-old lab mix has been tentatively diagnosed with lupus (or similar auto-immune disorder). He is on prednisone, which really helps his mobility but he also has terrible scabby patches of skin. Has anyone been able to keep an older dog with lupus going for a while? We are hoping for at least one more summer with him, but we will have to reconsider if the prednisone stops working and he gets lame again.

My akita is auto immune but doesn't have lupus. She was diagnosed 4 years ago and is now 7. I did however discuss with my vet a type of steroid that a dog could be on long term that doesn't have the same side effects as prednisone. The dog would need to be weened off the pred first. The downfall to the steroid was that it wasn't an immediate releif like the pred and it would need to build up in the system (i'm sorry i cant remeber the name of it). My thoughts would be to bring it up with your vet and see if it's a possibilty after your dog is stable on the pred. I also do not vaccinate. Not even rabies. It would over stimulate her immune system and kill her. Look into yucca root as well. It works as a natural steroid without the side effects, it's not as potent but could be used for comfort in the end. Best of luck.