Do I Have Crohn’s Disease or Ulcerative Colitis? Identifying Factors That Distinguish CD from UC and Indeterminate Colitis

Abstract

Inflammatory bowel diseases (IBD) are commonly defined as either Crohn’s disease or ulcerative colitis. There is substantial overlap, however, in clinical symptoms, genetics, and treatment response between the two. As such, it is not uncommon for your physician to change your diagnosis based on development of new clinical information over time. There are several factors that can help distinguish between the two diseases. In ulcerative colitis, inflammation only occurs in the colon; the area of inflammation is also continuous extending from the anus to an area in the colon where the inflammation ceases and there is normal-appearing colon. Crohn’s disease may also involve only the colon, termed Crohn’s colitis, which makes distinguishing between the two diseases difficult. In patients who have features of both Crohn’s colitis and ulcerative colitis, they are often given the diagnosis of “indeterminate colitis.” Crohn’s disease is more likely; however, if there is inflammation in the small bowel or upper GI tract, the inflammation occurs in a patchy distribution, or a patient has perianal disease (anal fistulas, fissures, or inflamed skin tags). In addition, long-standing bowel inflammation in Crohn’s disease may result in bowel narrowings, termed strictures, or abscesses adjacent to the bowel from connections, termed fistulas. There is also an interesting association between smoking and IBD. Although the majority of patients with Crohn’s disease are nonsmokers, patients who smoke and are diagnosed with IBD are much more likely to have Crohn’s disease, whereas ulcerative colitis is more common in former smokers and nonsmokers.