Proctosigmoiditis is a form of left-sided ulcerative colitis that affects the rectum and sigmoid colon rather than a larger area of the colon. It usually causes diarrhea.

Proctosigmoiditis affects the end of your colon and your rectum. 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.

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

Keep reading to learn about the symptoms of proctosigmoiditis, how doctors treat them, and what to expect.

Diarrhea is usually the most significant symptom for all forms of ulcerative colitis. Sometimes diarrhea occurs more than four times per 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 proctosigmoiditis include:

  • loss of appetite
  • weight loss
  • bloody diarrhea
  • pain on the left side of the abdomen

If you have rectal bleeding that is constant or bright red in appearance, it’s best to talk with a doctor. Blood in your stool can also occur with many serious health conditions that require prompt treatment, including colon cancer.

It’s important to get regular screenings for colon cancer, especially if you have ulcerative colitis.

Sometimes blood may cause your stool to look tarry or black. This happens when blood from an earlier part of the digestive tract is digested. You should seek emergency medical attention if you experience this 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, but researchers do not completely understand the causes behind 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 gastroenteritis
  • having a history of smoking cigarettes
  • living in an urban environment
  • using certain medications, including oral contraceptives, hormone replacement therapy, and nonsteroidal anti-inflammatory drugs (NSAIDs)

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

To diagnose ulcerative colitis, doctors typically perform a test known as a colonoscopy.

This involves using an endoscope, a special instrument with a lighted camera on the end. Your doctor inserts this into the rectum and lets the scope travel upward, visualizing the colon’s lining.

This test will help your doctor see areas of:

  • swelling
  • discoloration
  • inflamed blood vessels in your bowel

If you have proctosigmoiditis, it means the signs of ulcerative colitis do not extend beyond the sigmoid colon.

Treatment for proctosigmoiditis usually involves medication. You may take medication during an active flare-up and during periods of remission when symptoms go away or improve.

If symptoms are very severe and medications do not appear to help, a doctor may recommend surgery.

Medications

Proctosigmoiditis involves a small part of the colon and is usually associated with mild to moderate ulcerative colitis. Doctors usually treat it with 5-aminosalicylic acid (5-ASA), such as:

Doctors may prescribe it as mesalamine, an anti-inflammatory medication. Mesalamine is available in several forms, including:

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, doctors may recommend other treatments, including:

  • rectal corticosteroid foams
  • oral corticosteroids
  • biologics, which reduce the immune system response that causes inflammation

Surgery

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.

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

People with ulcerative colitis, including those with proctosigmoiditis, are generally at an increased risk of colorectal cancer.

Doctors typically recommend colorectal screenings 8 years after the initial diagnosis of ulcerative colitis for people with colon involvement.

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

Stress can trigger a flare of inflammatory bowel disease in people who have it.

This may be due to various reasons, including by impairing the function of the intestinal barrier, disturbing gut bacteria, affecting the speed at which contents pass through the intestines, and affecting the immune and neuroendocrine systems.

Inflammation in the bowels can cause pain and cramping, diarrhea, bleeding, and feeling urgency to go to the bathroom.

Proctitis refers to ulcerative colitis inflammation in the lining of the rectum.

Proctosigmoiditis refers to ulcerative colitis inflammation in the lining of the rectum and in the lower part of the colon, known as the sigmoid colon.

Proctosigmoiditis is a type of ulcerative colitis that affects the rectum and a small part of the colon. It can cause bloody diarrhea and other symptoms. Treatment usually involves medication to relieve flares.