The main difference between colitis and ulcerative colitis (UC) is the trigger. UC usually stems from autoimmune reaction. Other types of colitis may result from an infection or mediation use.

Colitis describes inflammation in the large intestine. Several conditions can lead to colitis, and UC is a common type. Doctors also categorize colitis into additional subtypes. Subtypes of colitis, including UC, may have different causes, but symptoms often overlap.

This article covers the similarities and differences between colitis and UC, including symptoms, causes, treatments, and other subtypes of colitis.

A man sitting in a medical waiting roomShare on Pinterest
MixMedia/Getty Images

The main difference between colitis and UC is the cause. UC usually develops due to an autoimmune reaction. The body’s immune system attacks healthy tissue of the large intestines.

Other types of colitis may also develop due to infection or medications. Some cancer treatments, such as immunotherapy, induce an inflammatory response and colitis.

Another differentiating factor of UC is how long the condition lasts. Although someone may experience a remission of symptoms, UC is a lifelong condition. Other forms of colitis may resolve.

As the colon becomes inflamed in both diseases, symptoms overlap between colitis and UC. Symptoms include:

Individuals with UC may also develop symptoms of inflammation outside of the large intestine that people with colitis do not. Additional symptoms may include:

Doctors diagnose both UC and colitis using similar techniques. After a review of symptoms, medical history, and physical exam, diagnostic tests help confirm a diagnosis. Tests may include:

  • a stool culture to check for pathogens, such as a calprotectin stool test
  • colonoscopy to view the large intestine
  • CT and MRI scans may show a thickened colon but are not specific enough as a diagnostic tool

Read more about UC diagnosis.

Treatment for UC may overlap with other forms of colitis and may include medication to manage diarrhea and treatment of inflammation of the intestine for both ulcerative colitis and colitis.

Additional treatment may depend on the specific type of cause of colitis. For instance, people with infectious colitis may require antibiotics. Someone with ischemic colitis may require medication to improve blood flow to the colon.

Read more about UC-approved drugs.

Although UC is the most common, there are other causes and forms of colitis. These include:

Ischemic colitis vs. UC

Ischemic colitis involves injury to the large intestine due to a lack of blood flow to the area. The colon needs constant blood flow to remain healthy. When that blood flow becomes interrupted, it can lead to damage.

Doctors may associate ischemic colitis with:

Microscopic colitis vs. UC

According to the National Institute of Diabetes and Digestive and Kidney Diseases, microscopic colitis involves colon inflammation that is only visible using a microscope.

While the exact cause of microscopic colitis is unclear, it is similar to UC. Possible causes include:

  • certain medications
  • smoking
  • genetics

Collagenous colitis vs. UC

Collagenous colitis is the second type of microscopic colitis. The colon also appears to be of typical thickness on a colonoscopy, but people with collagenous colitis develop collagen under the colon’s lining.

Lymphocytic colitis vs. UC

Lymphocytic colitis is one of two types of microscopic colitis. People with lymphocytic colitis have microscopic tissue differences in the colon, including increased white blood cells. The colon’s lining is often typical thickness, whereas, with UC, the large intestine becomes thicker than usual.

Infectious colitis vs. UC

Infectious colitis refers to inflammation in the colon due to a pathogen, such as bacteria, parasite, or virus.

In comparison, UC does not usually develop due to an infection, but in some cases, it may trigger an abnormal immune response leading to UC.

Acute colitis vs. UC

Acute colitis means intense or severe symptoms. Not all people with UC have severe symptoms all the time, but acute symptoms do occur.

About 25% of people with UC experience one or more acute episodes of colitis in their life.

Pseudomembranous colitis vs. UC

Pseudomembranous colitis develops due to an infection from Clostridium difficile. This type of bacteria is usually present in the intestine.

Typically, the body has enough good bacteria to keep C. difficile at bay. However, if good bacteria decrease in number, C. difficile can lead to colon inflammation. Pseudomembranous colitis often occurs as a complication of antibiotic use.

Nonspecific colitis vs. UC

Nonspecific colitis refers to colitis that does not have the same features as any other type of colitis.

A small 2019 study found that many people with colitis had a diagnosis of nonspecific colitis. Of the 80 study participants, 83.75% had a diagnosis of nonspecific colitis.

Segmental colitis vs. UC

Segmental colitis involves a long-term nonspecific form of inflammation that only affects a limited section of the colon, such as left-sided colitis. Doctors associate this condition with diverticulitis, which causes small pouches in the intestine lining.

Colitis and UC both involve inflammation of the large intestine. The diagnosis and treatment for both conditions tend to overlap.

The main difference between the two is the specific cause. UC results from an abnormal reaction in the immune system. Colitis can have several different causes, such as infections or certain medications.

Visit our dedicated IBD hub for more resources on UC.