Crohn's Disease vs. UC (Ulcerative Colitis): How To Tell the Difference

  • Medical Author:
    Charles Patrick Davis, MD, PhD

    Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.

  • Medical Editor: Bhupinder S. Anand, MBBS, MD, DPHIL (OXON)
    Bhupinder S. Anand, MBBS, MD, DPHIL (OXON)

    Bhupinder S. Anand, MBBS, MD, DPHIL (OXON)

    Dr. Anand received MBBS degree from Medical College Amritsar, University of Punjab. He completed his Internal Medicine residency at the Postgraduate Institute of medical Education and Research, Chandigarh, India. He was trained in the field of Gastroenterology and obtained the DPhil degree. Dr. Anand is board-certified in Internal Medicine and Gastroenterology.

What is Crohn's disease? What is ulcerative colitis (UC)?

Both Crohn’s disease and ulcerative colitis, or UC, are types of IBD (inflammatory bowel disease), but they are not the same disease. Crohn’s disease is a chronic inflammatory process with no known cause (idiopathic) that can affect any part of the gastroesophageal (GI) tract from the mouth to the anus. Ulcerative colitis (UC) also is a chronic and intense inflammatory process, with no known cause, but it is only confined to the large bowel.

People with Crohn’s disease have episodes of abdominal pain and diarrhea, followed by remission of symptoms. There is no medical or surgical cure for Crohn’s disease.
Ulcerative colitis symptoms and signs are predominantly left-sided lower abdominal pain with rectal bleeding, frequent stools, and a mucousy rectal discharge. There is no medical cure for UC, but surgical removal of the entire large intestine can cure it. However, there can be complications after surgery.

Crohn's disease sometimes is referred to as Crohn disease.

What causes Crohn's vs. UC?

Doctors and researchers don not know what causes both diseases, but they speculate that a number of factors such as genetics, heredity, mucosal immunity, gut microbes, diet, environmental factors, vascular problems, psychosocial problems, and certain drugs may be triggers that may participate in causing these diseases.

Crohn's and UC similar symptoms and signs

Both Crohn’s disease and ulcerative colitis have many similar symptoms.

Crohn's vs. UC differences between symptoms and signs

There are a few differences in the symptoms between UC and Crohn disease. Frequently, doctor’s cannot diagnose the cause of either disease by symptoms alone. However, for people with ulcerative colitis, the abdominal pain is often confined to the left side of the abdomen, while Crohn’s disease may have abdominal pain anywhere in the abdomen.

Which is worse, Crohn's disease or UC?

Although both Crohn’s disease and ulcerative colitis are chronic diseases, UC may be considered “worse,” as people with extensive and severe UC may require surgery. People over age 50 that need surgery have increased mortality due to colitis-associated postoperative complications.

Crohn's vs. UC triggers

Because the diseases have unknown causes, it is difficult to know what triggers their development. However, if you carefully note in a diary when symptoms reappear in Crohn’s disease or worsen in UC, you may be able to identify triggers that affect your disease.

What does Crohn's disease and UC look like (pictures)?

Picture of Crohn's Disease
Picture of Crohn's Disease
Ulcerative Colitis Illustration
Ulcerative Colitis Illustration

Quick GuideCrohn's Disease Causes, Symptoms, Diet

Crohn's Disease Causes, Symptoms, Diet

Is Crohn's Disease Contagious?

Researchers and doctors don't know the exact cause of Crohn's disease, but it is not contagious. They do know that it causes inflammation of the gastrointestinal tract (from mouth to the rectum), and it runs in some families (may be genetic).

How are these types of IBD diagnosed?

Doctor’s diagnose UC by endoscopy (sometimes with biopsy). During this procedure the doctor can see and take pictures of the patient’s abnormal gut mucosa (often with ulcers), and the presence of continuous disease (there are no areas of normal mucosa). Other blood tests and imaging tests like CT scan or MRI are used, but these tests are not definitive.

Doctors use the same procedures and tests to diagnose Crohn’s disease. However, they also use small bowel studies, colonoscopy, and upper GI endoscopy to identify the abnormal gut mucosa that usually occur in multiple areas anywhere in the intestinal tract. These areas are not continuous, but are separated by normal areas of intestinal mucosa that distinguish them from ulcerative colitis lesions.

Crohn's vs. UC differences between treatments

UC and Crohn’s disease treatments may include corticosteroids, anti-inflammatory agents, tumor necrosis factor inhibitors, immunosuppressants, antibiotics, Alpha 4 Integrin inhibitors and anti-diarrheal agents.

Crohn’s disease treatments also may include anticholinergic agents and bile acid sequestrants, if there is no bowel obstruction.

Severe UC may require surgical removal of the large intestine.

Treatments are complex, and some drugs should not be used for long time spans. You and your team (primary care and gastroenterologist) should discuss what treatment protocol you should follow.

What is the prognosis for Crohn's vs. UC?

The prognosis for both diseases is fair to good in individuals that respond to medical therapy and avoid known triggers that increase symptoms. Most people can have a normal lifespan. However, for people with severe ulcerative colitis that are 50 years of age or older and require surgery, their lifespan may be reduced due to colitis-associated postoperative complications.


Ghazi, L. "Crohn Disease." Medscape. Updated: Jan 06, 2017.

Basson, M. "Ulcerative Colitis. Medscape: Updated Feb 14, 2017.

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Reviewed on 7/24/2017

Ghazi, L. "Crohn Disease." Medscape. Updated: Jan 06, 2017.

Basson, M. "Ulcerative Colitis. Medscape: Updated Feb 14, 2017.

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