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Colonitis, more commonly referred to as colitis, is an inflammation of the large intestines. Both a condition and a symptom, colitis has several causes ranging from infections to autoimmune disorders, and its duration may be short- or long-term. Despite the different causes, affected individuals experience similar gastrointestinal symptoms, including diarrhea and abdominal pain. However, treatment of colitis is based on the cause of the condition.


The 2 most well-known types of colitis include Crohn disease and ulcerative colitis -- both of categorized as inflammatory bowel disease (IBD) and related to an abnormal response to the body’s immune system. According to statistics from the Centers for Disease Control and Prevention (CDC), as of 2015, 3.1 million people in the U.S. had a diagnosis of IBD. Other causes of colitis include infections, damage from chemicals, radiation therapy or medications, or restricted blood flow to the bowel -- called ischemic colitis. MIcroscopic colitis, a type of colon inflammation only seen when viewed microscopically, has an unclear cause but may be related to an abnormal immune response or medications.


Symptoms of colitis include diarrhea that may include blood or pus, abdominal pain and tenderness, gas, bloating, tiredness, loss of appetite, dehydration and weight loss. However, symptoms may differ depending on the types of colitis. Complications from severe symptoms include anemia, ulcers or holes that develop in the colon, poor absorption of nutrients into the body and infections.


There are numerous ways to diagnose colitis, and most often a colonoscopy is a starting point. Biopsy of the colon, stool cultures and other imaging tests are used to make a definitive diagnosis. People with colitis also need ongoing blood tests to assess health and nutritional status -- to determine the presence of anemia, malnutrition or to check for electrolyte abnormalities or other complications.


Treatment includes medications that reduce inflammation, manage pain, treat infections or modify the immune response so ongoing inflammation doesn’t occur. Nutrition therapy can help manage symptoms, prevent malnutrition or restore nutritional balance. Hospitalization may be needed to treat severe dehydration or manage other complications. Surgical removal of sections of the bowel may also be needed in severe IBD.

Warnings and Next Steps

If you have been diagnosed with colitis, follow up with your doctor regularly to help manage your condition and minimize future complications. If you have a long-term or chronic form of colitis, you will most likely work with a gastroenterologist to manage this condition. See a doctor right away if you have abdominal pain or diarrhea that does not improve, blood in your stool, or if you are so dehydrated you have symptoms such as dizziness, lightheadedness or decreased urination.