Hello Lisa and Welcome to Healing Well,
It sounds like you have had every test known to mankind. I would not even venture to guess as I have no idea. I feel so bad for you that your not able to be diagnosised and yet your obviously in pain and have a legitimate disorder.
It seems like your physician should ship your info to all the specialist in the field that he knows and see if anyone has any ideas? How about Mayo Clinic?
Just a thought. Please keep posting and know that I support you.
I just wanted to offer my condolences because I understand how ridiculously frustrating it is to be getting sicker and sicker with no real answers. If you've had scopes that show erythema, ulcerations, and edema, there's no doubt you have some form of colitis - has anyone mentioned the possibility of "collagenous colitis" or "microscopic colitis?" Have you gotten all of your physicians' records of your visits?
I'm astounded by the fact that even though you have confirmed colitis, you have not had treatment other than anti-spasmodics. You need to visit a major academic medical center for evaluation of this.