Crohn's / IBD

What is left-sided colitis?

Left-sided colitis is a type of ulcerative colitis, a condition that causes inflammation in the colon. Just as it sounds, left-sided colitis affects the left side of the colon.

Left-sided colitis has some specific symptoms and complications, so a thorough diagnosis is required to avoid confusing it with another disorder. 

There are also a few different treatment methods for the condition, but the treatment and management will vary from case to case.

What is left-sided colitis?

Left-sided colitis
The top circle illustrates colitis and the bottom circle illustrates a healthy section of the colon.

Left-sided colitis, or distal ulcerative colitis, is a form of ulcerative colitis that extends from the rectum up the colon and stops at the splenic flexure, which is the point where the colon bends. 

Ulcerative colitis is caused by an unusual response of the body’s immune system that leads to inflammation in the intestinal tract. This inflammation causes small ulcers in the lining of the colon that create mucus and pus and lead to other symptoms. 

Left-sided colitis is a chronic condition. Once diagnosed, people usually continue to experience symptoms throughout their lives. There is currently no known cure for ulcerative colitis. 


Symptoms of left-sided colitis are very similar to many other types of ulcerative colitis. Chronic diarrhea is the most common symptom of ulcerative colitis. 

Many people also complain of feeling the constant need to have a bowel movement. This sensation is called tenesmus and is caused by irritation and inflammation in the rectum. When people with ulcerative colitis do pass stool, it is usually a very small amount.

Other symptoms of ulcerative colitis include:

The stool may also have blood in it. Bloody stools can be a sign of significant damage in the colon. 

Anyone with blood in their stool should call their doctor for an appointment. More than just a small streak of blood may require emergency medical attention. 

Causes and risk factors

white pills spilling out of an orange medicine bottle
A history of antibiotic usage and infections may be a risk factor for ulcerative colitis.

There is no single cause of ulcerative colitis, but there are many theories about why it occurs. Some researchers believe ulcerative colitis is an autoimmune disorder that targets the digestive system.

What doctors do know is that there are many different risk factors for ulcerative colitis, including:

  • history of infections and antibiotic usage
  • family history of ulcerative colitis or other digestive disorders
  • living in a developed nation
  • living further from the equator

These risk factors are not causes of ulcerative colitis and do not mean that a person with them will get ulcerative colitis. Instead, they mean that people with them are more likely to develop the condition than those who do not have them.


Correctly diagnosing left-sided colitis is a critical step in its treatment. Doctors will usually perform an examination called an endoscopy, which uses a camera to get a better picture of the inside of the colon. 

Images captured from the endoscopy will help the doctors look for signs of inflammation, such as redness, water retention, and other irregularities.

In left-sided colitis, signs of the condition will disappear once the camera goes beyond the splenic flexure. This is typically how doctors differentiate between left-sided colitis and other forms of ulcerative colitis.


The treatment for left-sided ulcerative colitis will vary based on a few different factors. The severity of symptoms and how well someone responds to medications may alter their treatment options. 


Medications are currently the first line of treatment for ulcerative colitis. Depending on the diagnosis and severity of symptoms, doctors will prescribe one or more different medications to treat left-sided colitis. 


One of the most common and effective medications is called 5-aminosalicylic acid or 5-ASA. It can be taken orally, with an enema, or applied topically. 5-ASA helps reduce the inflammation in the colon.

Recent research noted that topical application of 5-ASA might be more effective than other delivery methods. Topical treatments induced remission in 72 percent of cases studied within four weeks of use. 

Researchers also noted that a combination of both oral and topical treatment is better than either form alone to reduce symptoms.


While 5-ASA is helpful in the majority of cases, some people do not respond well to it. In these instances, doctors use corticosteroids to help manage the inflammation. 

Oral corticosteroids can often be used alongside 5-ASA for a more complete treatment. 


In cases where both 5-ASA and corticosteroids fail, doctors may recommend immunosuppressant medications. These drugs target proteins in the immune system that spark the inflammation in ulcerative colitis. 


Severe cases of colitis may require hospitalization. In the hospital, a person will receive intravenous medications and steroids to reduce symptoms. 

In rare cases, doctors may recommend removing part of the colon. This is typically due to severe damage, inflammation, or bleeding in the affected area.


Left-sided colitis may also cause complications, including toxic megacolon and anemia.

Toxic megacolon is a frequent complication of inflammatory bowel disease that causes the colon to dilate as inflammation builds up. Symptoms include abdominal pain, fever, dehydration, and malnutrition

Toxic megacolon increases the risk of a ruptured colon. The condition is usually treated with medicines, intravenous fluids, and sometimes surgery. 

Anemia can be a further complication of left-sided colitis. Losing blood from the inflamed intestines can lead to low blood count or anemia. The condition is often treated with iron supplements or blood transfusions. 


turmeric root and powder on a board
Adding turmeric to the diet may help to manage ulcerative colitis.

Many people look to make a few diet and lifestyle choices to help them manage symptoms of left-sided colitis. More research needs to be done to verify that any natural methods are effective for ulcerative colitis symptoms.

For instance, probiotics may help reduce symptoms of active colitis but should not be seen as a treatment by themselves. Formulations made from these probiotics have proven to be very effective and are currently being studied in greater depth. 

There is also some evidence that people may find minor relief from acupuncture and wheatgrass.

Other natural supplements and dietary choices that may help ulcerative colitis include:

  • omega-3 fatty acids
  • probiotics
  • turmeric
  • folate and folate-rich foods

Most doctors will recommend eating a varied diet to support left-sided colitis treatment. Some people also feel a diet high in fiber, and low in refined carbs can help ease inflammation in the colon. 

Home remedies and alternative treatments for any kind of ulcerative colitis should be discussed with a doctor beforehand.

Other types of colitis

Left-sided colitis can cause symptoms similar to other forms of ulcerative colitis. It is important to understand the difference between the types of colitis and how they may affect a person. 

Ulcerative proctitis

Ulcerative proctitis is sometimes seen as the starting point for all forms of ulcerative colitis. People who develop ulcerative colitis are commonly diagnosed with ulcerative proctitis first. 

The symptoms and discomfort of ulcerative proctitis tend to be mild and cause few complications.

Total colitis

Unlike left-sided colitis, total colitis affects the entire colon. It often causes severe abdominal pain, chronic diarrhea, and weight loss. Total colitis causes extensive bleeding and often leads to toxic megacolon.


Proctosigmoiditis affects the rectum and sigmoid colon, which is the lowest segment of the colon close to the rectum. 

People with proctosigmoiditis often have bloody diarrhea and a constant feeling that they need to use the bathroom. Moderate pain and cramps in the abdomen are also common. 


Researchers still have much to learn about ulcerative colitis. While there is no cure for the condition, many people can greatly reduce their symptoms or put the condition in remission with proper treatment. 

Working directly with a doctor is the best way to create a manageable treatment plan and reduce the risk of complications.

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