Crohn’s Disease and Ulcerative Colitis

Crohn’s disease and ulcerative colitis are types of inflammatory bowel disease (IBD). Both conditions affect the digestive tract and cause a range of gastrointestinal issues, but there are differences.

See Gastrointestinal Conditions That Cause Chronic Abdominal Pain

Main Differences Between Crohn’s Disease and Ulcerative Colitis

Crohn's disease can occur anywhere in the digestive tract, from the mouth to the anus, and often shows up in "patches" throughout healthy tissue. Ulcerative colitis only affects the large intestine.

While Crohn’s disease and ulcerative colitis belong to the same category (IBD), there are differences between the two conditions:

  • Ulcerative colitis affects only the large intestine (colon). Crohn’s disease can affect any part of the gastrointestinal tract (from mouth to anus).
  • Crohn’s disease has both inflamed and healthy parts of the intestines. Ulcerative colitis will cause the entire colon to be inflamed.
  • Crohn’s disease occurs in all layers of the gastrointestinal tract. Ulcerative colitis only occurs in the outer most layer of the lining of the colon. The colon is made up of 4 layers and the top (innermost) layer, the mucosa, is the only one to come in direct contact with digested food.

These differences may seem slight; however, they are key to a correct diagnosis.


Symptoms: Is It Crohn’s Disease or Ulcerative Colitis?

Crohn’s disease and ulcerative colitis have similar gastrointestinal symptoms.

  • Abdominal cramping. This type of pain is often associated with diarrhea or constipation and generally comes and goes.
  • Abdominal pain. Abdominal pain can be dull, achy, or sharp. It can also be localized to one area, such as the left side in ulcerative colitis, or a general all over discomfort (more common in Crohn’s disease).
  • Diarrhea. This is the frequent passage of loose, watery, bowel movements. People with ulcerative colitis often have rectal bleeding as well.

These symptoms can range from mild to severe. Crohn’s disease is often considered episodic, meaning that a person will experience symptoms followed by periods of remission.

Usually, the symptoms of Crohn’s disease and ulcerative colitis are so similar that doctors cannot diagnose either without further testing.

Testing for Crohn’s Disease and Ulcerative Colitis

A doctor will typically call for diagnostic testing to determine whether a person has Crohn’s disease or ulcerative colitis. Diagnostic testing will help the doctor determine:

  • The type of IBD
  • The severity of the disease
  • The extent of inflammation in the gastrointestinal tract
  • Any additional complications

Below are the different ways a doctor may test for Crohn’s disease and ulcerative colitis.

  • Endoscopy and colonoscopy. This test uses a thin flexible tube (called an endoscope) and lighting system to explore the different parts of the digestive tract.
  • Lab tests. A standard blood test, fecal blood test, and antibody blood test may be given in order to rule out or support possible diagnoses. A blood test alone cannot determine whether a person has Crohn’s disease or ulcerative colitis.
  • X-ray. A doctor may perform a conventional x-ray or a contrast x-ray.
    • A conventional x-ray can show any narrowing or blockage within the intestines.
    • A contrast x-ray can show how a thick, chalky liquid moves through the gastrointestinal system. A person will either drink the liquid or receive a barium enema through the rectum depending on which part of the GI tract is being contrast x-rayed.
  • Computerized tomography (CT) scan. CT, or CAT, scans take several different x-rays to create a cross-sectional image.
  • Leukocyte scintigraphy. White blood cells are drawn to inflammation. Scintigraphy can track white blood cells to determine how much inflammation exists in the gastrointestinal tract.

More than one diagnostic test may be needed to determine if Crohn’s disease, ulcerative colitis, or another condition is causing symptoms.

Treating Crohn’s Disease and Ulcerative Colitis

Overall, Crohn’s disease and ulcerative colitis treatment have the same goals:

  • Reduce symptoms (decreasing inflammation)
  • Prevent symptoms or flare-ups
  • Improve quality of life

Both conditions use medication to control symptoms, including:

  • Antibiotics
  • Aminosalicylates
  • Corticosteroids
  • Immunomodulators
  • Biologics
  • Probiotic supplements1
  • Anti-inflammatory diet and supplements2

It may take a few tries to determine which medication, if any, helps to control symptoms. There are also side effects and risks associated with each, and therefore may not be suitable for all people.

Diet is an important part of treating Crohn’s disease and ulcerative colitis. There is not one diet in particular that is recommended for all people with either condition, so it is best to consult with a nutritionist in order to get a personalized food plan and determine what works best.

Surgery for Crohn’s disease
Generally, nonsurgical treatments are tried first before a person is considered for surgery. While surgery does not cure Crohn’s disease, it may help those people who do not respond to medication. Surgery for Crohn’s disease typically involves widening any narrow passages within the GI tract, called a strictureplasty, or removal of a portion or portions of the intestines. Sometimes, a person will have the rectum or colon removed.

Even after surgery, Crohn’s disease symptoms will reappear in 30 percent of people within 3 years, and 60 percent within 10 years.3


Surgery for ulcerative colitis
Like Crohn’s disease, nonsurgical treatments are tried before surgery is considered for ulcerative colitis. Surgery for ulcerative colitis includes the removal of the anus, colon, and rectum or just the colon and rectum. The former procedure diverts solid waste to a pouch attached to the body.

While surgery for ulcerative colitis is considered a cure by some, symptoms can still occur after the procedure.


  • 1.Alagón Fernández Del Campo P, De Orta Pando A, Straface JI, et al. The Use of Probiotic Therapy to Modulate the Gut Microbiota and Dendritic Cell Responses in Inflammatory Bowel Diseases. Med Sci (Basel). 2019;7(2):33. Published 2019 Feb 22. doi:10.3390/medsci7020033
  • 2.Reddavide R, Rotolo O, Caruso MG, et al. The role of diet in the prevention and treatment of Inflammatory Bowel Diseases. Acta Biomed. ;89(9-S):60–75. Published . doi:10.23750/abm.v89i9-S.7952
  • 3.Crohn’s Treatment, Crohn’s and Colitis website. Accessed June 11, 2019