Ulcerative colitis vs. Crohn's disease: What's the difference?

Inflammatory bowel disease (IBD) is characterized by a group of intestinal disorders that cause inflammation of the digestive tract. The two most common kinds of IBD are ulcerative colitis (UC) and Crohn’s disease. Often, patients with Crohn’s and UC present similar symptoms, such as abdominal pain, diarrhea, and rectal bleeding, but the two conditions are actually quite different. We look at the key distinctions between Crohn’s and UC.

Location of inflammation and symptoms

Both UC and Crohn’s disease cause chronic inflammation that affects the gastrointestinal (GI) tract. The main differences between these two conditions are the location of inflammation and the symptoms.

Ulcerative colitis is generally restricted to the colon (large intestine). Crohn’s disease, on the other hand, involves inflammation in any part of the GI tract, from the mouth to the anus. In Crohn’s, healthy parts of the intestine are mixed in with inflamed areas, but with UC, there is continuous inflammation of the colon.

It’s crucial to pay close attention to your symptoms if you suspect that you have IBD. A GI specialist will be able to interpret your symptoms and diagnose the kind of IBD you’re experiencing. 

Common ulcerative colitis symptoms include: 

  • blood in the stool with mucus
  • frequent diarrhea
  • loss of appetite
  • abdominal pain
  • urgent bowel movements
  • weight loss
  • tenesmus, or a strong urge to use the bathroom without necessarily having a bowel movement

Common Crohn’s disease symptoms include: 

  • abdominal pain and bloating
  • diarrhea
  • weight loss
  • constipation
  • blood in the stool
  • fevers
  • nausea
  • vomiting 

How to get the right diagnosis

If you’re experiencing symptoms of IBD, it’s best to see a doctor so that they can take a look inside and figure out what’s going on. In both cases, a doctor will examine blood and stool samples to help rule out viruses or other bacterial infections in the GI tract.

Routine laboratory tests, imaging studies (x-rays, CT scans, and MRIs), and endoscopic evaluation (colonoscopy, upper endoscopy, and sigmoidoscopy) can be helpful in establishing a diagnosis. X-rays can show places where your intestine is blocked or unusually narrow. CT scans and MRIs can detect inflammatory changes in the small and large intestines. Endoscopies utilize a very small camera on a tube to help doctors see inside your digestive system. 

People who live with IBD can find comfort in the wide array of resources available: support groups and advocacy group chapters, local events, online message boards, and helplines. 

Interested in participating in research? Volunteers are needed for IBD studies to accelerate treatments and interventions.