Fast Five Quiz: Diagnosis of Crohn Disease

Jaime Shalkow, MD


January 12, 2022

Crohn disease manifests in different locations, which can often inform the course of disease and influence treatment decisions. Population-based studies have shown that the condition is evenly distributed among ileal, ileocolonic, and colonic disease, with roughly one third of patients in each category. Risk factors for a more aggressive disease course include initial extensive bowel involvement, ileal/ileocolonic involvement, perianal/severe rectal disease, and presentation with a penetrating or stenosis disease phenotype.

In contrast to rectal involvement in patients with ulcerative colitis, one half of patients with Crohn disease and colitis have sparing of the rectum. Approximately 20%-30% of patients have perianal disease, and 4% have involvement of the mouth or gastroduodenal area (but studies suggest this percentage may be underestimated). Involvement of the esophagus and proximal small bowel is rare.

Under the Paris classification, a single patient can have both penetrating and stricturing disease phenotypes, though this is the least common phenotype.

Learn more about Crohn disease.


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