I personally think there is more blood supply and of course muscles in the rectum...and you might also have a hemorrhoid?
Many who have just ulcerative proctitis do find it's more difficult to get controlled. I believe suebear is one who was in that situation.
Could be because it is where all passes through.
You need more powerful rectal meds methinks.
Oh, did you recently taper down a pred dosage?
quincy