Proctosigmoiditis is a form of ulcerative colitis that affects the rectum and sigmoid colon. The sigmoid colon connects the rest of your colon, or large intestine, to the rectum. The rectum is where stool is expelled from the body.

Although this form of ulcerative colitis involves very little area of your colon, it can still cause significant symptoms.

Other types of ulcerative colitis include:

  • left-sided colitis (distal colitis): affects the colon from the descending section to the rectum
  • pancolitis: involves inflammation throughout most of the colon

Knowing what type of ulcerative colitis you have can help determine which type of treatment will be most effective.

About 50 percent of all people who are diagnosed with ulcerative colitis have proctosigmoiditis.

Diarrhea is usually the most significant symptom for all forms of ulcerative colitis. Sometimes diarrhea occurs more than four times a day.

Diarrhea is also the most common symptom. Your stool may have streaks of blood due to inflammation in the colon.

Damage and irritation to the rectum can cause you to feel like you constantly need to have a bowel movement. However, when you go to the bathroom, the amount of stool is usually small.

Other symptoms associated with ulcerative colitis include:

  • abdominal pain or rectal pain
  • fever
  • weight loss
  • constipation
  • rectal spasms

You shouldn’t ignore rectal bleeding that is constant or bright red in appearance. Sometimes blood may look tarry in your stool. You should seek emergency medical attention if you experience these symptoms.

Proctosigmoiditis is a result of chronic inflammation in the colon, like all types of ulcerative colitis. This inflammation is the result of an immune response. Doctors don’t know what triggers this immune response.

Some people are more likely than others to develop ulcerative colitis. The risk factors for all types of ulcerative colitis are the same. They include:

  • having a family history of ulcerative colitis
  • having a history of infection with Salmonella or Campylobacter bacteria
  • living at a higher latitude
  • living in a developed nation

These factors only increase the risks for ulcerative colitis. Having one or more of these risk factors doesn’t mean you’ll get the condition.


Proctosigmoiditis doesn’t involve a large portion of the colon. Therefore, the first treatment option is 5-aminosalicylic acid (5-ASA). Doctors may prescribe it in the form of mesalamine, an anti-inflammatory medication.

Mesalamine is available in several forms, including oral, suppository, foam, and enema. It’s sold under brand names like:

  • Lialda
  • Asacol
  • Pentasa
  • Apriso
  • Delzicol

Recent clinical guidelines recommend mesalamine enemas and suppositories over oral mesalamine for people with proctosigmoiditis.

Because proctosigmoiditis only affects the lower part of the colon, you can often use suppositories instead of enemas. You can take oral mesalamine if you can’t tolerate or administer enemas.

If you don’t respond to mesalamine, there are other treatments available. These include:

  • rectal corticosteroid foams
  • oral corticosteroids
  • infliximab (Remicade), which reduces the immune system response that causes inflammation


If you have severe diarrhea or bleeding, you may need to be hospitalized. In the hospital, you may be treated with intravenous steroids. Very severe cases may need surgery to remove the affected portion of the colon.

To diagnose ulcerative colitis, your doctor may perform a test known as a colonoscopy. This involves using an endoscope, which is a special instrument with a lighted camera on the end. Your doctor will insert this into the rectum and let the scope travel upward, visualizing the colon’s lining.

This test will help your doctor see areas of swelling, redness, and inflamed blood vessels in your bowel. If you have proctosigmoiditis, these signs of disease won’t extend beyond the sigmoid colon.

Like with other forms of ulcerative colitis, some complications of proctosigmoiditis include:

While people with ulcerative colitis are generally at risk for colorectal cancer, those with proctosigmoiditis probably aren’t. However, for many people with ulcerative colitis, the inflammation grows and affects more of their colon within five years of their diagnosis.

Proctosigmoiditis can’t be cured, but symptoms can usually be managed through treatment and lifestyle changes.