So, what is
Crohn’s disease?

Crohn’s disease is an inflammatory bowel disease (IBD) that is chronic, progressive, and varies in how it affects people. It can create inflammation anywhere in the digestive tract, leading to symptoms like diarrhea, abdominal pain, fatigue, fever and weight loss.

On this page, you’ll find info about:

IBD? IBS? Where does Crohn’s fit in?

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


Inflammatory Bowel Disease

is a chronic disease, like Crohn’s, that causes inflammation and damage to the gastrointestinal (GI) tract.


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 Crohn’s disease
the same thing as ulcerative colitis (UC)?

Short answer: No. Crohn’s and UC are both inflammatory bowel diseases (IBD). Both are associated with ongoing inflammation of the GI tract, but they’re not the same.

Let’s look at the differences between Crohn’s and UC: 

CROHN’S can involve any portion of the digestive tract—from the mouth to the anus. This is why someone with Crohn’s may have sores in their mouth.  
UC is limited to the colon and rectum. 

PEOPLE WITH CROHN'S may feel pain on the right side. 
PEOPLE WITH UC may feel pain on the left side. 

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

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

Diagnosing Crohn’s:
put it to the tests

If you’ve been experiencing recurring GI symptoms, and think you might have Crohn’s, schedule an appointment with your primary care doctor or a gastroenterologist. Don’t have a gastroenterologist yet? We can help you find one here.

When you see your doctor, they may mention tests and procedures that help diagnose Crohn’s and determine how severe it is. Here are some tests you could hear about:

Imaging Tests

Doctors rely on visual evidence of IBD to diagnose and monitor Crohn’s. Imaging tests give them the evidence they need in the form of pictures and video. These tests can also help them find possible complications that may require ongoing monitoring. 


This test uses a thin, flexible tube with a lighted camera inside the tip (called an endoscope) that allows doctors to explore different parts of the GI tract. An endoscopy enables them to see signs of inflammation to help determine the severity of Crohn’s. It’s also an important procedure doctors use to monitor Crohn’s 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 Crohn’s, they’re important tools in diagnosing and monitoring it. These are only some of the blood and stool tests used for Crohn’s. There are others your doctor may recommend.


Indexes are a type of test that your doctor can administer during an appointment. These tests can include questions about your health as well as physical findings related to Crohn’s disease (for example, a sore in your mouth).

A commonly used index is the Harvey-Bradshaw Index. It allows physicians to measure Crohn's disease severity. It can be used along with modified patient-reported outcomes and physician-reported outcomes to assess the severity of Crohn's disease and detect remission in a noninvasive and cost-efficient manner.

GI Tract Icon

Crohn’s can affect different parts of the GI tract.

There are five different types of Crohn’s disease based on what area of the GI tract is affected: ileocolitis, ileitis, gastroduodenal Crohn’s disease, jejunoileitis, and Crohn’s (granulomatous) colitis. No matter the type of Crohn’s disease, all require a gastroenterologist to diagnose and create a treatment plan tailored for each person.

Next page:

Let’s dive into Crohn’s Disease Symptoms & Flare-ups


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