Colitis refers to the inflammation of the lining of the colon. Many different conditions can cause this to happen.

The most common type of colitis is ulcerative colitis. With this type, ulcers or sores develop in the stomach. The inflammation extends from the rectum along the inner lining of the colon.

Types and causes of colitis may differ, but most symptoms overlap. How the condition affects an individual varies from person to person.

This article will discuss the different types of colitis. It will also look at the causes and risk factors, as well as when to contact a doctor.

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Colitis refers to inflammation within the lining of the colon. This can occur due to several different conditions. The main two are ulcerative colitis and Crohn’s disease, both of which are types of inflammatory bowel disease (IBD).

With colitis, the lining of the colon becomes inflamed as a reaction to harmless bacteria and molecules present in food.

Colitis is often a lifelong condition, and there is currently no cure. However, there are treatment options available to help manage the condition.

Colitis typically develops when people are within the age brackets of 15–35 years or 55–70 years.

Ulcerative colitis is the most common variation of colitis. It begins in the rectum and spreads up the colon in different ways, depending on the type.

People with chronic ulcerative colitis may experience episodes of acute severe colitis during their lifetime.

Acute severe ulcerative colitis is a condition that can be life threatening and almost always requires hospitalization to balance out fluids and electrolytes and, in some cases, to obtain nutritional support.

Although most people do not experience extreme flare-ups, an estimated 20% of those with chronic colitis may experience a severe flare-up that requires hospitalization.

Learn more about ulcerative colitis here.

Some types of ulcerative colitis include:

Ulcerative proctitis

This type of colitis is limited to the rectum. The Crohn’s & Colitis Foundation note that there is not an increased risk of cancer.

Symptoms of ulcerative proctitis can include:

  • rectal pain
  • urgent bowel movements
  • rectal bleeding

Left sided colitis

Inflammation begins at the rectum and continues along the left side of the colon. It can also include proctosigmoiditis, which affects the rectum and lower part of the colon above the rectum, or the sigmoid colon.

Symptoms of left sided colitis may include:

  • weight loss
  • appetite loss
  • pain on the left side of the abdomen
  • bloody diarrhea

Extensive colitis

This condition affects most of the colon. In the case of pancolitis, it affects all of the colon.

Symptoms of extensive colitis include:

  • weight loss
  • appetite loss
  • bloody diarrhea
  • abdominal pain

Causes

Ulcerative colitis can occur due to:

  • genetics
  • atypical immune reactions
  • the microbiome of the digestive tract
  • environment

Crohn’s colitis is one of several types of Crohn’s disease. Unlike other variations of the condition, Crohn’s colitis only affects the colon.

Symptoms overlap between Crohn’s conditions, but people with Crohn’s colitis are more likely to develop skin lesions and joint pain.

Some other symptoms include:

  • rectal bleeding
  • diarrhea
  • abscesses, fistulas, and ulcers around the anus

Causes

Crohn’s colitis may occur due to:

A healthcare professional can only see microscopic colitis with a microscope.

There are two types of microscopic colitis: lymphocytic and collagenous.

With the lymphocytic type, there is a higher number of white blood cells than usual, and the lining of the colon is of a normal thickness.

With the collagenous type, the layer of collagen under the epithelium is thicker than usual.

The symptoms of each type are similar. A person will typically experience watery diarrhea that does not contain blood.

Some other signs and symptoms include:

Causes

Microscopic colitis may occur due to:

Autoimmune conditions

In these cases, a person’s immune system attacks its own cells. Autoimmune conditions that may be a cause include:

Medications

Medications that may be associated with microscopic colitis include:

  • NSAIDs, such as aspirin
  • acarbose
  • lansoprazole
  • sertraline
  • ranitidine
  • ticlopidine

Infections

Bacterial and viral infections may cause inflammation of the gastrointestinal tract.

Bile acid malabsorption

Bile acid is a fluid that helps carry waste out of the body.

Bile acid malabsorption occurs when the intestines are unable to reabsorb the bile acid. If it reaches the colon, it can lead to diarrhea.

Another type of colitis is ischemic colitis. It occurs due to a reduced blood flow to the colon.

A person may experience abdominal cramping and pain. Within 24 hours, they may notice bloody stools.

Other ischemic colitis symptoms include:

  • diarrhea
  • nausea
  • vomiting
  • bloating

An older 2012 article states that there are three main categories of ischemic colitis:

  • gangrenous
  • stricturing
  • transient

Most people have the transient type, which causes milder symptoms, but some have the gangrenous type.

Gangrenous ischemic colitis is particularly severe. People with this condition are likely to require surgical intervention when symptoms appear.

Learn more about ischemic colitis here.

Cause

Ischemic colitis occurs due to a lack of blood flow to the colon. This can happen for a variety of reasons, such as heart disease and other conditions that affect blood flow.

Pseudomembranous colitis is usually the result of Clostridium difficile bacteria.

These bacteria are always present in the body, but there are usually enough “good” bacteria to override them.

When these good bacteria die, often after a person has taken antibiotics, the presence of C. difficile increases, causing inflammation in the colon.

Cause

Pseudomembranous colitis can occur due to taking medications that destroy healthy bacteria, such as antibiotics.

Colitis can also come from conditions that are not related to IBD. One of these is cytomegalovirus (CMV), which is a common strain of the herpes virus.

One 2020 article notes that symptoms can be nonspecific and mimic those of IBD. However, a person may experience:

  • abdominal pain
  • diarrhea
  • fever
  • rectal bleeding
  • weight loss
  • feelings of discomfort

Rectal bleeding and diarrhea appear to be the most common symptoms.

If a person with CMV develops symptoms of colitis, they should contact a doctor as soon as possible.

Learn more about CMV here.

Cause

CMV is a strain of the herpes virus that affects approximately 70% of the general population. It does not typically cause any symptoms.

However, symptoms can occur, especially in those with a compromised immune system.

Treatment options will depend on the type and severity of symptoms that a person is experiencing.

There are different types of medications that a doctor may suggest, including:

  • aminosalicylates
  • corticosteroids
  • biological drugs

If medication does not work, the doctor may suggest surgical intervention.

Surgery may also be desirable to people who are benefiting from medication but still finding that the condition affects their quality of life.

There is no way to prevent colitis. However, a person can take steps to help manage the condition and reduce its symptoms.

These steps include:

  • not smoking
  • eating a healthful diet
  • avoiding carbonated drinks
  • avoiding caffeine
  • avoiding alcohol
  • avoiding high fiber foods
  • consuming lots of water
  • keeping a food diary to help identify triggers

Research indicates that people who smoke are twice as likely to experience IBD than people who do not smoke. This is because of a certain protein in the lungs that smoking can activate.

Learn more about natural remedies for managing ulcerative colitis here.

Colitis is not typically fatal. However, it is a lifelong condition that can have life threatening complications.

For example, some types of colitis — such as Crohn’s disease or ulcerative colitis — can increase the risk of developing colon cancer. Microscopic colitis, on the other hand, does not increase the risk of developing colon cancer.

Learn more about the potential complications of ulcerative colitis here.

Additionally, a person’s outlook depends on the type of colitis they have.

For CMV colitis, for example, the outcome is favorable. It can even resolve without antiviral treatment in approximately 25% of people.

It is always best for a person to make a doctor aware if they believe that they have colitis. Even if medical treatment does not seem necessary, the support can be beneficial.

People should contact a doctor if they experience any of the following symptoms:

  • abdominal pain or cramping
  • bloody diarrhea
  • an urgent need to have a bowel movement
  • blood in the stool
  • rectal bleeding
  • weight loss

If a person thinks that they may have acute severe ulcerative colitis, they need medical attention immediately.

When the inner lining of the colon becomes inflamed, it is known as colitis.

This can be the result of several conditions. However, the most common type is ulcerative colitis.

If a person develops colitis, they are likely to experience abdominal discomfort, rectal bleeding, weight loss, bloody diarrhea, and an urgent need to have a bowel movement.

A person should contact a doctor if they suspect that they are experiencing colitis.