Was this helpful?

What is colitis?

The term colitis refers to any kind of swelling or inflammation of the large intestine (colon). The large intestine is part of the digestive system. It is located near the end of the digestive tract, after the small intestine and before the rectum and anus. The primary functions of the large intestine are to absorb fluids from food remnants and produce stool, or feces.

A wide variety of diseases, disorders and conditions can cause colitis. These include:

The wide variety of causes makes it difficult to estimate how many Americans are affected by colitis. For instance, it is estimated that 1.4 million Americans have inflammatory bowel disease, which includes both Crohn’s disease and ulcerative colitis. However, inflammatory bowel disease is just one possible cause of colitis. Consequently, it is likely that millions of Americans suffer from some form of colitis (Source: CCFA).

Common symptoms of colitis include abdominal bloating, pain or cramping, bloody stools, diarrhea, excessive gas, and a constant urge to have a bowel movement. Treatment of colitis depends on the underlying disease, disorder or condition. The goal of the clinical evaluation is to identify the root cause(s) of the problem. Once the underlying cause is diagnosed, it is important for you to follow the treatment plan you and your healthcare professional design specifically for you to reduce the risk of potential complications.

In some cases, colitis can quickly progress from a mild condition to a life-threatening situation. Seek immediate medical care (call 911) for serious symptoms, such as bloody and frequent diarrhea, painful bowel movements, vomiting, and abdominal tenderness, especially when the abdomen is pressed on. These symptoms may be combined with pale or blue lips, fast heart rate, shallow breathing, weakness, and anxiety. Seek prompt medical care for colitis symptoms that recur or are persistent.

What are the symptoms of colitis?

Symptoms of colitis depend on the specific type of colitis and its cause. Symptoms generally affect the digestive tract, but can also include fever, chills and dehydration.

Common symptoms of colitis

Depending on the cause of colitis, you may experience colitis symptoms daily or just once in a while. At times any of these colitis symptoms can be severe:

  • Abdominal bloating
  • Constant urge to have a bowel movement
  • Diarrhea
  • Weight loss

Serious symptoms that might indicate a life-threatening condition

Some cases of colitis can quickly progress from a minor condition to a life-threatening situation, such as toxic megacolon (rapid, extreme widening of the colon) and shock. Seek immediate medical care (call 911) if you, or someone you are with, have colitis and any of the following symptoms:

  • Abdominal tenderness when the abdomen is pressed

  • Bloody diarrhea or bloody stool (the blood may be red, black or tarry in texture)

  • Change in alertness of level of consciousness, such as lethargy or passing out

  • Fast or uneven heart rate or palpitations

  • Frequent diarrhea

  • Painful bowel movements

  • Shallow breathing

  • Symptoms of dehydration (loss of body fluids that can cause excessive thirst, dry mouth, light-headedness, dizziness, little or dark-colored urine, and weakness)

  • Weakness (loss of strength)

Symptoms that might indicate a serious condition

In some cases, the symptoms of colitis may indicate a serious condition. Seek prompt medical care if you have any of these symptoms:

  • Diarrhea lasting longer than two or three days

  • Mild to moderate abdominal pain

  • Nausea and vomiting that prevent you from keeping down liquids

  • Recurring bouts of diarrhea

What causes colitis?

Many different diseases, disorders and conditions can cause colitis. Colitis can be a sign of inflammatory disorders, intestinal infections, lack of blood flow to the colon, and side effects of radiation or medication treatment. Because of the range of possible causes of colitis, a correct diagnosis of the underlying disease, disorder or condition is very important. Contact your healthcare provider for a physical exam.

Colitis is categorized based on the underlying disease, disorder or condition.

Infectious causes of colitis

Colitis may arise from acute (sudden) or chronic (long-lasting) intestinal infections by viruses, bacteria and parasites including:

  • CMV colitis (infection caused by cytomegalovirus)

  • Cryptosporidium enterocolitis (parasitic infection)

  • Food poisoning from a wide variety of pathogens, such as botulism, cholera, E. coli, Listeria, Salmonella, Shigella and viruses

  • Pseudomembranous colitis (overgrowth of Clostridium difficile caused by antibiotic therapy)

Inflammatory causes of colitis

Inflammatory causes of colitis include:

  • Crohn’s disease (inflammatory bowel disease that can affect any part of the digestive tract)

  • Microscopic colitis (inflammatory condition that must be diagnosed by looking at cells with a microscope; sometimes called collagenous colitis and lymphocytic colitis)

  • Ulcerative colitis (inflammatory bowel disease that only affects the colon)

Other causes of colitis

Other causes of colitis can include:

  • Antibiotic-associated colitis
  • Irritable bowel syndrome (IBS; digestive discomfort that does not cause intestinal damage or serious disease)

  • Ischemic colitis (insufficient flow of blood to the colon)

  • Necrotizing enterocolitis (disorder that primarily affects premature or sick infants and results in death of large intestine tissue)

  • Radiation of the colon

What are the risk factors for colitis?

Depending on the underlying disease, disorder or condition, a number of factors may increase your chances of developing colitis. Similarly, preventing colitis depends on the specific type and cause of colitis. Some common risk factors include:

  • Exposure to food, water, soil, or other substances contaminated by viruses, bacteria or parasites that cause intestinal infections

  • Family history of irritable bowel syndrome, Crohn’s disease, ulcerative colitis, or other type of colitis

  • Premature birth

  • Smoking

How is colitis treated?

Treatment of colitis depends on the underlying disease, disorder or condition. The goals of treatment are to relieve symptoms and correct the underlying problem if possible.

Infectious colitis is treated based on the organism (bacteria, virus or parasite) that is known or likely to be causing the infection. Antibiotics may be used for bacterial infections. Supportive treatments and treatments aimed at preventing dehydration and relieving symptoms may also be part of the treatment plan for infectious colitis.

Inflammatory causes of colitis are generally treated with anti-inflammatory medications, such as mesalamine and sulfasalazine. Other classes of medications used to treat inflammatory colitis include:

  • Antibiotics

  • Biologic therapies such as infliximab (Remicade)

  • Corticosteroids such as prednisone

  • Immune modifiers such as azathioprine (Imuran)

Other types of colitis are treated based on the underlying disease, disorder or condition. For example, treatment of irritable bowel syndrome is aimed at relieving symptoms. Ischemic colitis is treated by trying to restore blood flow, relieving symptoms, and performing surgery if necessary.

Other treatments for colitis

Other methods for controlling colitis include a variety of therapies, lifestyle, and dietary interventions, and possibly surgery. Additional treatments of colitis include:

  • Dietary changes, such as drinking extra fluids to prevent dehydration, eating a low-fat diet, and limiting dairy products and any other foods that seem to aggravate your symptoms

  • Getting regular exercise

  • Intravenous nutrition to ensure adequate nutrition if you are unable to eat because you need to rest your gastrointestinal tract

  • Intravenous rehydration and electrolyte replacement if frequent diarrhea has resulted in the loss of excessive fluid and electrolytes, causing severe dehydration and electrolyte imbalances

  • Reducing stress

  • Regular medical care to monitor symptoms, modify treatment plans as needed, and watch for possible complications

  • Smoking cessation program if you smoke

  • Surgery to remove a damaged colon and rectum. This major surgery, called a proctocolectomy, involves joining your remaining small intestine to the abdominal wall and connecting an external pouch to collect intestinal waste. Restorative proctocolectomy, or ileoanal pouch-anal anastomosis (IPAA), is a newer procedure that involves connecting the end of the small intestine directly to the anus, thus preserving your ability to pass feces through the anus.

What are the potential complications of colitis?

Complications of untreated or poorly controlled colitis can be serious and life threatening. You can best treat colitis and lower your risk of complications, or delay the development of complications, by following the treatment plan you and your healthcare professional design specifically for you.

Colitis can lead to serious complications including:

  • Dehydration

  • Fistulas (abnormal holes between the gastrointestinal tract and other areas of the body, such as the vagina, bladder and skin). Fistulas can become seriously infected and cause other problems.

  • Intestinal bleeding

  • Intestinal perforation or rupture of the intestinal wall

  • Intestinal ulceration

  • Malnutrition

  • Peritonitis

  • Shock

  • Toxic megacolon

Was this helpful?
Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2021 Jan 19
THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.
  1. What is Ulcerative Colitis? Crohn’s and Colitis Foundation of America.
  2. Colitis. Medline Plus, a service of the National Library of Medicine National Institutes of Health.
  3. Food poisoning. Medline Plus, a service of the National Library of Medicine National Institutes of Health.
  4. What Are Crohn’s & Colitis. Crohn’s and Colitis Foundation of America.
  5. Motility Disorders of the Large Intestine. International Foundation for Functional Gastrointestinal Disorders.
  6. Necrotizing enterocolitis. Medline Plus, a service of the National Library of Medicine National Institutes of Health.
  7. Shock. Medline Plus, a service of the National Library of Medicine National Institutes of Health.
  8. Toxic megacolon. Medline Plus, a service of the National Library of Medicine National Institutes of Health.