Hey there; I have UC, and have for seven years.
I can’t believe a doctor would say mesalamine and prednisone are the only options. There are other options, it’s just that they’re a little more heavy-duty than mesalamine (but obviously that’s not an option for you). Definitely look for a new GI.
Steroids are not a long-term treatment option. Even for people without your underlying conditions, they tend to have terribly unplesasant side effects and can put you at risk of all sorts of stuff. They generally put people into remission quickly (although they never did for me) and then you need to use a different drug longterm for maintenance. That’s what the Asacol was supposed to be for. But if you can’t take that, the next step up is 6-mercaptopurine, also known as 6-MP or Imuran. It’s an immunosuppressant. Since UC is caused by an overactive immune system, it often treats UC successfully. But of course it puts you at risk of getting infections since your immune system is now compromised.
If 6-MP doesn’t work, the next class of drugs is biologics, namely Remicade or Humira. These are not pills (Remicade is an infusion you must get in hospital every 6 weeks, Humira is a self-injection every 2 weeks) and come with their own set of risks.
Finally, ulcerative colitis can be cured, but the cure is getting your entire colon removed. I had this done nearly 3 years ago. You have options – a permanent ileostomy (extrenal bag worn on the belly) or j-pouch, which is an internal reservoir created out of the tissues of the small intestine to serve as a replacement for the colon. J-pouch has more risks but can be worth it if you’re not willing to be saddled with an ostomy for the rest of your life. I have a j-pouch and so far it’s going okay but there are problems. It is much better than my life with UC was though. The surgical process is grueling (1 surgery for ileostomy, 2–3 for j-pouch), so it’s not recommended unless UC is severely hampering your quality of life.
Let me know if you have any more questions.