How deep are the lesions of Ulcerative colitis?

Ulcerative colitis primarily affects the mucosal layer of the colon. The lesions are indeed superficial, typically limited to the innermost lining (the mucosa) and sometimes the submucosa. This is important because it differentiates ulcerative colitis from other inflammatory bowel diseases, such as Crohn's disease, which can affect deeper layers of the intestinal wall and lead to transmural lesions.

In ulcerative colitis, the inflammation is continuous and arises in a symmetrical manner, starting in the rectum and potentially extending proximally. The superficial nature of the lesions is also relevant in terms of treatment and management, as interventions can often focus on topical therapies that target the mucosal surface. Understanding this characteristic helps guide clinical approaches and predict complications associated with the disease.