Comparing 5 Types of Ulcerative Colitis (UC)

Ulcerative proctitis

Ulcerative proctitis is the mildest form of UC, in which the inflammation is confined to the rectum (the final portion of the colon, just above the anus).

It’s relatively common — 25 to 55% of people with UC first present with proctitis. Typical symptoms include:

• Rectal bleeding (blood in or on stool)
• Rectal pain or discomfort
• Sense of urgency (feeling you must pass stool)
• Tenesmus (constantly feeling you need to have a bowel movement)
• Mild diarrhea or mucus in stool

Because the disease is localized, the risk of complications is lower than in more extensive forms. Treatments are often applied directly to the rectum via suppositories, enemas, or foams.

Left‑sided colitis (distal colitis)

Sometimes called distal colitis, left‑sided colitis involves inflammation that starts in the rectum and extends up through the sigmoid colon or descending (left) colon, often up to the splenic flexure (the bend near the spleen).

About 17% of people with UC present with left-sided colitis at the time of diagnosis. The symptoms of left-sided colitis tend to be more pronounced than in proctitis. These may include:

• Bloody diarrhea (more frequent, looser stools)
• Abdominal cramps, often on the left side
• Urgency and tenesmus
• Weight loss or reduced appetite

Left-sided colitis is often treated with topical therapies. In some cases, oral or intravenous medications may be helpful.

Proctosigmoiditis  

Proctosigmoiditis is like left‑sided colitis, but more limited: inflammation in the rectum and sigmoid colon only (the lowest portion). It doesn’t extend as far up as the descending colon.

Many sources group it under left‑sided colitis. The symptoms of proctosigmoiditis may be milder than typical left-sided colitis. These include:

• Rectal bleeding
• Bloody diarrhea or mucus in stool
• Urgency and tenesmus
• Some cramping on the lower left side

As with other forms of left-sided colitis, proctosigmoiditis can be treated with topical and systemic medications.

Extensive colitis (pancolitis)

Also called extensive or widespread colitis, pancolitis means the inflammation covers most or all of the colon (cecum) — from the rectum through the splenic flexure into the transverse colon, ascending colon, or beyond.

This is one of the more severe and extensive forms. Many people with UC go on to develop pancolitis as the disease evolves.

Symptoms tend to be more intense and systemic:

• Frequent, bloody diarrhea (often several times per day)
• Abdominal pain or cramps, often across the abdomen
• Weight loss, appetite loss, fatigue
• Fever or malaise

Because more of the colon is affected, the risk of complications — including colon dilation, perforation, and colon cancer — is higher. Surgical intervention is more likely in severe cases.

Fulminant colitis

Fulminant colitis, sometimes called acute severe colitis, is a rare, life‑threatening flare of UC.

It’s not a separate anatomical type, but a critical stage where inflammation is severe, possibly affecting much of the colon. This increases the risk of complications like perforation, toxic megacolon (colon enlargement), and bleeding.

Symptoms escalate dramatically. This includes:

• Very frequent bloody diarrhea (often many times per day)
• Severe abdominal pain
• Distension (swollen belly)
• Fever and tachycardia (fast heart rate), which could be a sign of shock or systemic illness

Fulminant colitis is a medical emergency. It’s usually treated with intravenous steroids, biologics, or surgery.

What to expect from diagnosis

The diagnostic workup is broadly similar, regardless of type:

• History and physical exam: This involves reviewing symptoms like bleeding, diarrhea, urgency, and pain. They may ask about your medical history.
• Blood tests: These are conducted to look for signs of inflammation, anemia, and electrolyte levels.
• Stool studies: Stool studies may rule out Clostridioides difficile and other bacterial infections.
• Colonoscopy with biopsy: This imaging test is the gold standard for diagnosing UC. It involves looking at the colon lining and testing tissues to confirm ulceration and rule out Crohn’s disease and other conditions.
• Imaging (CT, MRI, abdominal X-rays): These scans can help monitor and diagnose any complications.

Once you receive a diagnosis, your clinician may classify disease severity (mild, moderate, or severe) based on your symptoms and their findings.

Developing a care plan for UC

Treatments aim to induce remission by controlling inflammation and healing the mucosa. They also aim to maintain remission (in other words, to prevent flares).

Common treatments include:

• Topicals: Suppositories, enemas, and foams are the first-line treatment for mild to moderate UC.
• Systemic therapies: Oral medications, including corticosteroids, immunosuppressants, and biologics, may be used for moderate to severe UC.
• Targeted immunologic drugs: Specific immunologic drugs may be used in cases that don’t respond to typical treatment.
• Surgery: If systemic and topical treatments don’t work, or if you experience complications, you might need a colectomy (removal of the colon).

Many people with UC benefit from supportive care like diet adjustments, nutritional support, and frequent monitoring for complications.

The bottom line

UC is a chronic inflammatory disease of the colon. There are several types categorized by how far the inflammation has spread. The type of UC you have affects symptoms, risks, and treatment choices.

With careful monitoring, adherence to therapy, and collaboration with a gastroenterologist, many people with UC can maintain remission and a good quality of life.

If you suspect UC or have recently received a diagnosis, it’s important to work with a specialist to diagnose, treat, and monitor your condition.