Medically reviewed by Jenny Blair, MD 

Ulcerative colitis (UC) raises your risk for certain health complications, some of which may be life-threatening. These issues can occur within your digestive system, or they can be extraintestinal, meaning they involve other parts of your body. And while some people with UC develop multiple complications, others may not face any at all. Whatever your experience, it’s important to speak with your healthcare provider (HCP) if you notice suspicious symptoms.

Although many of these complications are rate, it’s still key to stay informed about your health. Here are the must-know facts about these important complications of UC.

1. Bleeding

Bleeding is familiar to many with UC; it may lead to iron-deficiency anemia, a condition where your body doesn’t have enough functioning red blood cells. Often, it comes from ulcers in the large intestine, “and just like if you have a scrape on your skin, it bleeds,” says Sushila Dalal, MD, a gastroenterologist at the University of Chicago Medicine in Illinois.

Since bleeding can also be caused by hemorrhoids, anal fissures and rarely, colorectal cancer, it bears reporting to your medical team, she adds. They can pinpoint the source and adjust treatment accordingly.

2. Fulminant colitis and toxic megacolon

A serious issue complicating about 1 in 10 first UC attacks, fulminant colitis is acute, severe inflammation of the colon. Occasionally, it progresses to toxic megacolon, a life-threatening complication where the large intestine stretches and dilates, impeding movement of gas. “It blows up almost like a balloon,” says Dalal, “and that can lead to a perforation in the colon.” Fever, abdominal pain, more than 10 loose stools per day and continuous bleeding are among the symptoms of fulminant colitis, and should prompt you to seek medical help immediately.

3. Colon cancer

People with UC have a higher colorectal cancer risk, especially if colitis affects much of the colon or if they have a liver condition called primary sclerosing cholangitis. The odds also increase with UC duration; after 35 years, up to 30 percent of patients will develop colorectal cancer. To help detect it early, Dalal recommends sticking to a regular screening schedule “even if the disease is in remission and the patient’s feeling completely well.” Typical UC patients should have a screening colonoscopy 8 years after diagnosis, and then every 1 to 3 years afterward, depending on previous colonoscopies and the advice of your HCP.

4. Dehydration

Colitis patients may be at higher risk of becoming dehydrated. Frequent diarrhea is one contributor, as are UC-related surgeries, like the removal of your colon. Sometimes, UC patients may even purposely restrict fluid intake, Dalal says, “because they’re trying to limit the number of bowel movements.”

Dehydration symptoms include intense thirst, fatigue and dizziness. To help prevent it, Dalal advises staying consistent with fluid intake and monitoring your urine color. “Make sure urine looks clear—it’s not dark and yellow,” she says, since a darker hue indicates your body is trying to hold on to scarce fluid.

Woman struggling with eye pain due to ulcerative colitis complications

5. Eye problems

Though eye issues connected to UC won’t typically threaten your vision, they can be painful and annoying. Sometimes medications trigger problems, while other times they’re related to UC itself. Uveitis is the most common; it’s an inflammation of the eye wall that often comes with redness, pain and light sensitivity. Generally it will subside with your UC, Dalal says, though it may require steroid eye drops. She recommends reporting any new visual symptoms to your HCP, “because they likely will need some further testing.”

6. Arthritis

Arthritis, or joint inflammation, is very common in UC patients. Many develop peripheral arthritis, which frequently affects larger joints like shoulders, hips and knees, but won’t damage them permanently. Since it’s usually related to disease activity, says Dalal, “oftentimes, once we heal the colon, the joint pain will improve as well.”

Another type, axial arthritis, affects joints around the lower spine and may turn up years before UC symptoms arise. A small percentage of patients may develop ankylosing spondylitis, a serious complication where the vertebrae in the spine can fuse. Physical therapy can be helpful with spinal issues, and doctors may prescribe medication.

7. Osteoporosis

Osteoporosis causes your bones to become weaker and likelier to break. Frequently, it’s related to drugs used to treat UC. “A lot of times our patients need steroids to induce remission,” says Dalal. “We know that steroid use can cause bone loss, and ultimately osteoporosis.” The longer you use steroids, the greater your chances. To help slow or prevent bone loss, your HCP may prescribe medications or supplements like calcium or vitamin D. They may also perform a bone density test, especially if you’re on steroids for an extended period.

8. Skin conditions

Though several skin conditions are linked to UC, the most common are erythema nodosum (EN) and pyoderma gangrenosum (PG). With EN, you’ll see tender red bumps, usually on the lower leg. Frequently linked to flare-ups, it often resolves with remission. That’s not always the case for PG, which may not mirror disease activity.

Also commonly found on the legs, PG presents with raised purple sores that can lead to ulcers. While treating UC is a good way to address skin issues, medication can help manage associated pain.

The Importance of Sticking with Treatment

Ultimately, while medication, surgery or other interventions are necessary to address some complications of UC, sticking to your treatment plan is crucial for all of them. “The best thing you can do,” says Dalal, “is to maintain a good remission and make sure the disease is completely controlled.”


Kristen Sturt is a New Jersey-based writer specializing in health and wellness. Previously, she was an editor at Sharecare and Grandparents.com (now Considerable.com), as well as a longtime writer at VH1. For kicks, she cooks, travels and spends time with her husband and two children.

Jenny Blair is a writer and journalist covering science, medicine, and the humanities. She earned her MD at Yale University, then completed a residency in emergency medicine at the University of Chicago. After several years in practice, she transitioned to working with words and ideas full-time. Jenny has contributed to Discover, New Scientist, Washington Spectator, and Medtech Insight, among other publications. She lives in New York City.

Oshi is a tracking tool and content resource. It does not render medical advice or services, and it is not intended to diagnose, treat, cure, or prevent any disease. You should always review this information with your healthcare professionals.