Okay, so what
is ulcerative colitis?

In short, ulcerative colitis (UC) is a chronic disease that affects the innermost lining of the large intestine (colon and rectum). The underlying inflammation that causes ulcerative colitis can be treated by working with a gastroenterologist.

On this page, you’ll find info about:

IBD? IBS? Where does UC fit in?

Ulcerative colitis is an inflammatory bowel disease (IBD), not to be confused with irritable bowel syndrome (IBS). While IBD and IBS have similar symptoms and may seem interchangeable, they’re actually pretty different.


Inflammatory Bowel Disease

is a chronic disease, like ulcerative colitis, that causes inflammation and damage to the colon.


Irritable Bowel Syndrome

is a disorder that can affect muscle contractions of the bowel and is not categorized by intestinal inflammation or damage to the GI tract.

Is UC the same as Crohn’s disease?

No. While Crohn’s and ulcerative colitis have some similarities—both being inflammatory bowel diseases and causing inflammation—they’re different in important respects.

Some of the differences between Crohn’s and ulcerative colitis include:

UC INFLAMMATION usually starts in the rectum and lower colon, and it can spread continuously to the entire colon.
CROHN’S INFLAMMATION can penetrate the bowel wall and appear in patches in the entire GI tract.

PEOPLE WITH UC can often have bloody stools.
PEOPLE WITH CROHN'S don’t usually see blood in their stools.

PEOPLE WITH UC may feel pain on the left side, while the specific location depends on the type of UC.
PEOPLE WITH CROHN'S typically feel pain on the lower right part of the abdomen.

Testing for ulcerative colitis: how is it done?

If you have recurring symptoms, it is best to schedule an appointment with a gastroenterologist who specializes in treating IBD.

If they suspect that you may have ulcerative colitis, they’ll likely perform certain tests and procedures to help confirm or rule out the diagnosis. Here are some of the more common diagnostic tests:

Imaging Tests

Doctors rely on visual evidence to diagnose ulcerative colitis. Imaging tests provide a clearer view of where ulcerative colitis is active in the colon and spot possible complications. Some imaging tests for ulcerative colitis that are used for diagnosis and monitoring are listed below—but there are others your doctor may recommend.


Endoscopy uses a thin, flexible tube with a lighted camera inside the tip (called an endoscope) that allows doctors to explore different parts of the colon. An endoscopy can show signs of inflammation and help your gastroenterologist determine the severity of ulcerative colitis. It’s also an important test in helping doctors monitor UC activity over time.  

Endoscopy can also include tests like:

Additional Imaging Tests

When your doctor needs to evaluate a larger portion of your intestine or outside the bowel, radiologic exams or diagnostic imaging like these tests will be performed.

Blood Tests and Stool Tests

Even though blood and stool tests alone can’t diagnose ulcerative colitis, they’re important tools in diagnosing and monitoring it. Below are some of the tests used for ulcerative colitis.


When you visit a doctor, they can administer a type of test called indexes. These tests may include a list of questions about your health but also information related to physical findings of ulcerative colitis.

The Mayo Score is an index for ulcerative colitis. It has a set of questions for a patient and a set of questions for their doctor. Answers are rated on a scale of 1-3. The final score helps a doctor to determine the severity of your ulcerative colitis.

Is there more than one type of UC?

Yes. There are three types based on how much of the colon is affected: proctitis, left-sided colitis, and extensive colitis (pancolitis). Each one can affect you in different ways. Make sure to talk to a doctor about any symptoms you may be experiencing so they can determine the specific type of ulcerative colitis you have and what the most effective treatment can be.

Next page:

Let’s unpack UC Symptoms & Flare-ups


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