Welcome to HealingWell, Disbooner.
There are several differences in UC and Crohn's. As you pointed out, UC is limited to the colon while Crohn's can affect any part of the GI tract. Another difference is that UC is almost always continuous, meaning the inflammation starts at point A and ends at point B and there is no uninvolved area between. In Crohn's, there may be patchy areas affected with healthy tissue between. A third difference is that UC affects only the innermost layer of the intestinal wall. Crohn's can affect the whole thickness of the intestinal wall; thus the much higher incidence of fistulas in Crohn's disease.
Regarding your symptoms, give the Asacol a couple of weeks. If you're still worse at that point, call your GI. Some of us are unable to tolerate Asacol and will get increased diarrhea and cramping with it. Usually we are able to tolerate other sorts of 5-ASA's such as Balsalazide.
Some people have indeterminate IBD, which means they have some features of Crohn's and some of UC. Generally speaking, the colonoscopy and biopsy findings are more reliable for diagnosis than the Promethius test.
Moderate to severe left-sided UC (21 cm) diagnosed 2001.
Avascular necrosis in both shoulders is my "forever" gift from steroid therapy.
Colazal, Remicade, Nature's Way Primadophilus Reuteri. In remission since April, 2006.
Co-Moderator UC Forum
Please remember to consult your health care provider when making health-related decisions.