Crohn’s disease is a chronic digestive disorder that affects more than half a million people in the U.S.

Crohn’s, one of the two major types of inflammatory bowel diseases (the other is ulcerative colitis), can lead to a range of potentially severe complications, including:

  • painful irritation of the digestive tract
  • infection
  • malnutrition

This condition can be identified by the presence of lesions in the intestines known as cobblestone ulcers.

Observing cobblestone ulcers and other key symptoms is essential in developing an effective treatment plan.

Cobblestone ulcers, which can be seen during a colonoscopy, got their name because groupings of the deep ulcers look like cobblestones. The presence of cobblestone ulcers helps doctors distinguish Crohn’s disease from ulcerative colitis because the two conditions share many of the same symptoms. But cobblestoning is unique to Crohn’s.

Cobblestone ulcers are the result of inflammation in the intestines of a person with Crohn’s. Unlike ulcerative colitis, which tends to thin the lining of the intestines and present with long, continuous sections of inflammation, Crohn’s causes a thickening of the intestinal wall.

Also, Crohn’s is characterized by patches of inflamed tissue — as opposed to uninterrupted areas of the affected intestinal lining.

Other types of ulcers common in people with Crohn’s

Crohn’s can trigger the formation of a few different types of ulcers, aside from cobblestone ulcers. A few other common types include:

  • aphthous ulcers, also known as canker sores, which form in the mouth along the gum line
  • longitudinal ulcers that can be round or irregular in shape and are often the first type of ulcers to form in the intestines
  • rake ulcers, which look as though a rake scraped shallow ragged marks along the lining of the intestines

The primary method of detecting cobblestone ulcers and diagnosing Crohn’s is through a colonoscopy, according to a 2018 study on the diagnostic guidelines for inflammatory bowel disease.

A colonoscopy is an outpatient procedure usually performed by a gastroenterologist. The day before the colonoscopy, you will clear your bowels with a special diet of clear liquids and the consumption of laxatives.

For the procedure itself, you will be given a sedative and will lie on your side. The doctor will guide a colonoscope, a thin, flexible tube through the rectum and up into the colon. The tube contains a small video camera that sends images to a computer monitor next to the doctor. This way the doctor can clearly see the lining of the colon and rectum. If polyps are observed, they can be removed.

If other cobblestone ulcers and other signs of Crohn’s are identified, the doctor will use the colonoscope to remove small tissue samples from different parts of your intestinal tract to be analyzed in a lab.

Crohn’s symptoms tend to flare up and enter periods of remission, largely based on how you respond to medications and changes to your diet and lifestyle. When symptoms are present, some of the most common include:

  • abdominal cramps
  • diarrhea
  • weight loss

Other signs of Crohn’s may include some or all of the following:

  • anemia
  • fatigue
  • fever
  • joint pain
  • nausea
  • poor appetite
  • skin irritation, including bumps that form just under the skin surface

The American Cancer Society recommends colonoscopies to screen for colorectal cancer starting at age 45, unless your doctor determines you are at a higher risk. In that case, your first colonoscopy may be performed at a younger age.

If Crohn’s is suspected based on a physical examination and other symptoms, a doctor may order a colonoscopy and other screening tests regardless of age. The onset of Crohn’s usually occurs when a person is in their 20s, though it sometimes presents at a younger age.

Other types of imaging tests and blood tests are also used to diagnose Crohn’s disease.


While a colonoscopy can provide a detailed and comprehensive view of the large intestine and rectum, an upper gastrointestinal (GI) endoscopy can give your doctor a similar look at the upper portion of your digestive tract.

The doctor guides an endoscope, which is similar to a colonoscope, down through the esophagus and into the stomach and duodenum, a section of the small intestine that connects to the stomach.

A special, longer endoscope can be used to reach down into the small intestine for a screening called enteroscopy.

CT scan

Your doctor may also order a computerized tomography (CT) scan, which takes x-rays to create computerized images of your digestive tract.

Blood tests

A blood test is usually recommended if Crohn’s is suspected. If your white blood cell count is abnormally high, it’s likely your body is dealing with inflammation and/or infection. Red blood cells that are fewer in number or smaller in size indicate anemia.

Physical examination

Of course, diagnosing Crohn’s also involves a physical examination, in which a healthcare professional will listen with a stethoscope to your abdomen and gently tap or press on parts of your abdomen to check for enlargement of your liver or spleen.

Crohn’s and ulcerative colitis are the two most common types of IBD, and they share many symptoms. However, inflammation in the intestines caused by Crohn’s can lead to a thickening of the intestinal wall and the formation of painful ulcers that appear as patches of cobblestones.

No such ulcer pattern is present with ulcerative colitis.

If you have Crohn’s symptoms, such as frequent episodes of abdominal cramps and diarrhea, see a doctor. You may be advised to have a colonoscopy, a test that can identify cobblestone ulcers and confirm a diagnosis of Crohn’s. The sooner you have a proper diagnosis, the sooner you can begin treatment and start to manage this chronic condition.