The large intestine, also called the colon, is the upside down U-shaped organ that consists of the ascending, transverse, descending,and sigmoid colon. The rectum is the last portion of the large intestine.
The large intestine (also called the colon) consists of the ascending, transverse, descending,and sigmoid colon. The rectum is the last portion of the large intestine.

What is ulcerative colitis?

Ulcerative colitis causes irritation and ulcers (open sores) in two parts of the large intestine (also called the colon): the last segment of the colon called the rectum (where poop is stored) and anywhere in the remainder of the colon (the upside down U-shaped tube above the rectum). It belongs to a group of conditions called inflammatory bowel disease (IBD). It can cause diarrhea and cramping. If it gets worse, you might see blood in the stool.

The inflammation in ulcerative colitis starts in the rectum, which is close to the anus (where poop leaves your body). The inflammation can spread and affect the rest of the colon. You might have more severe symptoms if the colon is affected. You could also have severe inflammation in the rectum and very mild inflammation in the colon.

If you have ulcerative colitis, you may notice a pattern of flareups, when symptoms are worse. During times of remission, you might have little to no symptoms. Remission can last for weeks to years.

What’s the difference between colitis and ulcerative colitis?

Colitis means your colon is inflamed, or irritated. This can be caused by many things, such as infections like food poisoning. Ulcerative colitis is more severe because it causes sores in your colon, can affect both the colon and rectum, and can be lifelong.

How common is ulcerative colitis?

Ulcerative colitis isn’t a common condition. Together with Crohn’s disease, another inflammatory bowel disease, it affects up to 1.3% of Americans.

Who gets ulcerative colitis?

Ulcerative colitis can develop in anyone at any age. Your chance of getting it is slightly higher if you:

What causes ulcerative colitis?

Researchers think the cause of ulcerative colitis is complex and involves many factors. They think it’s probably the result of an overactive immune response. The immune system’s job is to protect the body from germs and other dangerous substances. But sometimes your immune system mistakenly attacks your body, which causes inflammation and tissue damage.

What are the symptoms of ulcerative colitis?

Ulcerative colitis symptoms often get worse over time. In the beginning, you may notice:

  • Diarrhea or urgent bowel movements.
  • Abdominal (belly) cramping.
  • Tiredness.
  • Nausea.
  • Weight loss.
  • Anemia (reduced number of red blood cells).

Later you may also have:

  • Blood or pus in bowel movements.
  • Severe cramping.
  • Fever.
  • Skin rashes.
  • Mouth sores.
  • Joint pain.
  • Red, painful eyes.

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