Ulcerative colitis (UC) is a condition causing inflammation of the bowel, including the colon and rectum. Doctors name the condition by how far along the colon it reaches. Severe UC can lead to a complication known as toxic colitis.

Graphic showing the anatomy of different types of ulcerative colitis, including proctitis, proctosigmoditis, left-sided, extensive, and pancolitis.Share on Pinterest
Infographic by Jason Hoffman

UC is a form of inflammatory bowel disease (IBD). A person may develop different types of UC. Depending on the endoscopy results and symptoms, the condition can be mild, moderate, or severe.

Doctors categorize UC according to how much it has affected the large intestine. Inflammation and ulceration of the inner lining of the colon and rectum can cause redness, swelling, and pain, which may also extend to the whole colon.

There is currently no cure for UC, but it is possible to manage symptoms with medications, lifestyle changes, and, in severe cases, surgery. The extent of the inflammation and the severity of the condition help guide the management and treatment of UC.

This article provides an overview of UC types, including causes, symptoms, diagnosis, and treatment.

Proctitis is the development of inflammation limited to the rectum. It can be acute (short term) or chronic (long lasting).

One possible cause of proctitis is UC, but it may also result from:

Proctitis may develop farther in the colon and lead to other forms of UC, including left-sided UC or pancolitis.

Symptoms

Common symptoms of proctitis include:

  • an urgent need to have a bowel movement
  • constipation or diarrhea
  • cramping or pain in the rectum, in the anus, or to the left of the abdomen while having a bowel movement
  • bleeding from the rectum or blood in stool
  • stools with mucus or pus

If a person has pain in the abdomen or passes pus, mucus, or blood while having a bowel movement, they should seek immediate medical attention.

Treatment

First-line treatment will likely involve drugs to help reduce inflammation.

Doctors will also prescribe 5-aminosalicylic acid (5-ASA), also called mesalamine, via suppository once or twice per day, depending on the severity of the condition.

Mesalamine is a treatment only for UC proctitis. Other drugs doctors use to help treat proctitis may be similar to the ones that treat other types of UC, such as corticosteroids and biologics.

If the drugs do not relieve symptoms, a doctor may offer surgery to remove part of the affected area of the colon.

Proctosigmoiditis is similar to left-sided UC but does not affect the colon as extensively. The condition only affects the rectum and lower part of the colon — the sigmoid colon.

Symptoms

The condition causes:

  • loss of appetite
  • unexplained weight loss
  • bloody diarrhea

Treatment

Treatment for mild to moderate ulcerative proctosigmoiditis includes mesalamine suppositories and enemas. Treatment for more severe proctosigmoiditis can involve steroids and biologic therapy.

A doctor may provide alternative treatments or diets that will not trigger proctosigmoiditis or other types of UC.

Inflammation of left-sided, or distal, UC starts from the rectum and continues into the colon as far as the bend in the colon by the spleen. The condition affects the rectum and the lower part of the colon that attaches to the rectum.

Symptoms

Symptoms can include:

Treatment

Treatment for left-sided UC is similar to that for other types of UC and includes individual or a combination of IBD medications.

People with left-sided inflammation may also receive 5-ASA drugs in oral form or enemas.

Pancolitis, or extensive colitis, is an advanced form of UC that has spread through the entire colon. People with pancolitis or more than left-sided UC have a higher risk of developing colon cancer than individuals without UC.

Symptoms

Symptoms of pancolitis are similar to those of other forms of colitis, including:

  • diarrhea with blood
  • pain in the abdomen
  • an urgent need to empty bowels
  • unexplained weight loss
  • fever

Treatment

Treatment for pancolitis is similar to those for other forms of UC and includes:

  • medications
  • lifestyle and dietary changes
  • surgery, where necessary

Toxic colitis, which doctors sometimes also call fulminant colitis, is a complication of severe UC. It may result in perforation of the bowel, sepsis, and possibly death.

Symptoms

Symptoms include more than six bloody stools per day. There will also be signs of toxicity, such as:

Learn more about this severe case of UC.

Treatment

Important components of a treatment plan for toxic colitis include:

  • treating the underlying cause
  • addressing any electrolyte imbalances, such as hypokalemia
  • managing symptoms
  • preventing further complications

A healthcare professional may admit a person to an intensive care unit in case of an unexpected worsening of symptoms. Doctors will start by checking the person’s complete blood count and electrolyte levels every 12 hours.

The person will need to stop taking any medication that may irritate the colon, such as opioids and anticholinergics. However, they will receive intravenous (IV) fluids to provide adequate hydration. IV administration involves delivering medication or other fluids directly into a person’s bloodstream with the use of a thin tube or catheter inserted into a vein.

Due to a high risk of perforation, doctors frequently prescribe antibiotics.

The person will also need to be on bowel rest. This means they will not have any food or drink by mouth so the digestive tract can rest. As symptoms continue to improve, they can gradually start drinking and eating by mouth to promote gut healing.

If this treatment does not improve the condition, a surgical procedure, such as a colectomy, may be necessary.

Ulcerative colitis and Crohn’s disease are both inflammatory bowel conditions. They have some similarities and differences.

The main similarities are the following:

  • Both conditions usually result in inflammation of parts of the digestive tract.
  • There is no known cause of either, but it may include the microbiome, environmental factors, and genetics.
  • Both conditions disrupt food digestion, nutrition absorption, and waste elimination.
  • There is no cure for either of the conditions. However, people may be able to relieve symptoms with diet and medications.
  • Both conditions may increase the risk of colon cancer, lymphoma, and skin cancer due to treatment.

Colitis mainly affects the large intestine or colon and usually starts at the rectum. By contrast, Crohn’s disease can occur anywhere in the digestive system and usually develops in the lower small bowel and upper colon.

A person should visit a healthcare professional if they develop symptoms suggestive of colitis, including:

  • blood in stool
  • abdominal pain and cramping
  • urgent and frequent need to have a bowel movement

During the visit, a healthcare professional may:

  • check a person’s medical history and medication
  • ask about their lifestyle, including smoking
  • perform a physical examination
  • order some tests to rule out infection

The outlook for people with colitis will depend on the severity of their initial condition and how much of the bowel it has affected.

People can manage mild cases, which involve just the rectum or a small portion of the colon, and flare-ups at home. A person can manage symptoms with medication or lifestyle changes, which may lead to remission or a period with no symptoms.

A 2019 study notes that colitis may develop farther along the colon the longer a person lives with the condition. This may lead to more frequent flare-ups and require more medication.

UC can develop as a mild, moderate, or severe condition. It affects the body’s ability to process food and eliminate waste.

The extent to which UC affects the colon will determine what type of condition a person has. Doctors will diagnose the type of UC based on the location of the inflammation.

Individuals can usually manage their condition with diet, medication, and regular checkups. In severe cases, a person may require surgery.