Crohn’s disease and ulcerative colitis are both inflammatory bowel diseases with many similarities. Nevertheless, there are some key differences between the two conditions that affect how they are managed.

Both Crohn’s diseases and ulcerative colitis cause digestive distress and inflammation in the gastrointestinal tract. However, unlike Crohn’s disease, ulcerative colitis is linked to a response of the immune system.

The differences between Crohn’s disease and ulcerative colitis are explored in detail below.

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Crohn’s disease is a chronic inflammatory condition of the gastrointestinal (GI) tract. It belongs to a group of conditions known as inflammatory bowel diseases (IBD).

Crohn’s disease most often affects the end of the small intestine and the beginning of the colon, but it may also affect any part of the GI tract from the mouth to the anus.

Like Crohn’s disease, ulcerative colitis belongs in the IBD group as well. Ulcerative colitis is a chronic disease that affects only the colon (large intestine).

Ulcerative colitis happens when the immune system overreacts and mistakes the lining of the colon, as a foreign object to be attacked.

This immune overreaction causes the lining of the colon to become inflamed and develop ulcers or small open sores. These may produce mucous and pus.

The combination of inflammation and ulceration causes abdominal discomfort and frequent bowel movements, among other symptoms.

Crohn’s disease and ulcerative colitis are examples of IBD. Both can have very similar symptoms, including the following that can be aggravated by diet and stress:

  • abdominal pain or discomfort
  • bloody stools
  • cramping
  • constipation
  • overactive bowel movements
  • fevers
  • loss of appetite
  • weight loss
  • abnormal menstrual cycles in women

Both diseases are chronic conditions that can affect either men or women. Though doctors are unclear what causes either disease, researchers suspect genetic factors are involved in their onset.

However, despite their similarities, the two diseases are distinct and should be treated accordingly. Misdiagnosis can lead to incorrect treatment and continued suffering.

The symptoms of both diseases are very similar. Because of this, it is nearly impossible to diagnose or determine if a person has Crohn’s disease or ulcerative colitis, by looking at symptoms alone.

One difference between the two diseases is that Crohn’s affects the entire GI tract, whereas ulcerative colitis affects only the colon.

As a result, some people whose Crohn’s disease is present closer to the stomach, may be more likely to experience nausea and vomiting.

Early diagnosis for both diseases is similar. A doctor will ask a person several questions before they do a physical exam. Questions may concern:

  • general health
  • diet
  • family history
  • environment

In both cases, a doctor will examine blood and stool samples to help rule out viruses or other bacterial infections in the GI tract.

To determine which disease a person has, a doctor will need to perform tests for both. Running tests for only one may result in a misdiagnosis. A correct diagnosis is imperative, as treatment is different for the two diseases.

After a cursory exam, an endoscopy, where an instrument resembling a snake with a camera and light on the end, is threaded through the GI tract, may be performed. The types of endoscopy will vary between the two diseases.

For Crohn’s disease, there are two types of endoscopy, as follows:

  • Colonoscopy: The flexible tube, known as an endoscope, is inserted through the anus to allow for an examination of the colon.
  • Upper endoscopy: The flexible tube is inserted through the mouth, down the esophagus, into the stomach, and into the first part of the small intestine.

By contrast, ulcerative colitis involves the endoscope insertion through the anus only. The two types are:

  • Sigmoidoscopy: This allows the doctor to examine the rectum and lower colon for the extent and degree of inflammation in those areas.
  • Total colonoscopy: This occurs when the doctor examines the entire colon.

Both Crohn’s disease and ulcerative colitis are likely to involve a biopsy or small sample of tissue taken from the infected areas for examination under a microscope.

However, in people with Crohn’s disease, a doctor may wish to take X-rays of both the upper and lower GI tract to get an image of what is going on, prior to doing a biopsy or endoscopy.

If a person has chronic ulcerative colitis, a doctor may recommend a chromoendoscopy, which is a test where blue dye is applied to the GI tract. This looks for changes in the lining of the intestine, showing precancerous changes known as dysplasia.

Finally, to help diagnose Crohn’s disease, a doctor may use imaging to examine parts of the small intestine that cannot be reached with a colonoscopy. Again, these techniques typically involve dyes that show up well in images.

Ulcerative colitis would not be seen in these images, as it does not go up into the small intestine.

Both diseases respond well to a variety of treatments. These can include:


Both diseases can be controlled through the proper use of medications that target the body’s inflammatory responses. Reducing inflammation can reduce and eliminate many of the shared symptoms of the diseases, such as pain and diarrhea.

In addition to targeting symptoms, medication can also be used to decrease the frequency of flares, in what is known as maintaining remission. As proper treatment is administered over time, periods of remission can be extended, and periods of symptom flares can be reduced.

Both diseases have several types of medication that are available.

Combined therapies

In some circumstances, a doctor may recommend an additional therapy to the initial one to increase its effectiveness.

For example, combination therapy may add in biologics with an immunomodulator. As with all therapies, there are benefits and risks associated with combination therapy.

Combining therapies can increase the effectiveness in treating the diseases, but there may be an increased risk of side effects and toxicity.

Nutrition and diet plans

Both diseases have a tendency to reduce a person’s appetite. Foods are not responsible for causing either disease but people tend to find that modifying what they eat, based on what aggravates their symptoms, is helpful.

Diet modifications vary between individuals and disease. For example, a person with Crohn’s disease may find a bland diet is best during a flare and may eat foods that a person with ulcerative colitis would not be able to tolerate.

In both cases, proper nutrition is essential. So, people with either disease should keep a food journal and be aware of what upsets them.

Also, a meal plan can help an individual ensure they get enough nutrients. In either case, a doctor can help develop a meal plan that will avoid aggravating symptoms and provide adequate nutrition.


This treatment varies in frequency and location between Crohn’s disease and ulcerative colitis.

Medical treatment is the mainstay for both Crohn’s disease and ulcerative colitis. Surgery is reserved for those cases where there are complications, such as perforation of the bowel, excessive bleeding, cancerous growth, or severe inflammation not controlled with medications. Crohn’s disease may eventually come back later in life after surgery. In contrast, the removal of the colon and rectum, which is done in the case of ulcerative colitis, is considered a cure, as the disease no longer has a place to reside.

Surgery for either disease has a number of potential risks and will require recovery time. A doctor should discuss with the individual the possible benefits and risks of surgery before recommending a procedure.