What Is Ulcerative Colitis? Symptoms, Causes, Diagnosis, and Treatment

Ulcerative colitis (UC) is a type of inflammatory bowel disease (IBD) in which the lining of the large intestine (colon) becomes inflamed.

The colon then develops ulcers (open sores) that produce blood, pus, and mucus.

The small intestine is rarely affected.

There are several subtypes of ulcerative colitis, which are named according to the part of the colon affected:

• Ulcerative proctitis, which affects only the rectum
• Proctosigmoiditis, which affects the rectum and lower segment of the colon (sigmoid colon)
• Left-sided colitis, which affects the rectum, sigmoid colon, and descending colon up to the sharp bend near the spleen
• Pan-ulcerative or total colitis, which affects the entire colon, according to the Mayo Clinic.

The most common symptoms of ulcerative colitis are abdominal pain and diarrhea, which often contains blood or pus.

Symptoms of the disease typically develop gradually and come and go.

Periods without active disease — known as remission — may last for months or even years.

Over time, ulcerative colitis can progress to cover more of the colon. This typically leads to more severe disease and greater symptoms.

If left untreated, UC can also lead to a number of complications, including:

• Malnutrition
• Perforated colon
• Osteoporosis
• Liver disease
• Colorectal cancer
• Toxic megacolon

Learn More About Ulcerative Colitis Symptoms

Ulcerative colitis is believed to be caused by an abnormal response by your body’s immune system.

Your immune system is supposed to defend you against harmful invasive bacteria and viruses. But in some people, the immune system mistakenly attacks the body’s own tissue.

In ulcerative colitis, this may happen when the body mistakes food and helpful bacteria for harmful substances. It may also come about when the body doesn't turn off its response to fighting an infection.

Experts believe that ulcerative colitis develops because of a combination of environmental factors and genetic predisposition.

Fatty cold-water fish — such as mackerel, tuna, salmon, sardines, and herring — are rich sources of omega-3 fatty acids.

To diagnose ulcerative colitis, your doctor will first take a complete medical history and rule out other possible causes of your symptoms.

This will be done with a combination of your history of symptoms, lab tests, imaging scans, and a view of the inside of your colon using a flexible tube and camera (colonoscopy or sigmoidoscopy).

Medications are the main treatment for ulcerative colitis. Other treatment options include dietary changes and surgery, if necessary.

Drugs for ulcerative colitis work by reducing inflammation in your colon.

Some drugs are commonly used for maintenance therapy — to help you stay in remission — while others are used to treat disease activity during flares. You’re likely to need a combination of drugs for optimal treatment.

Surgery may be necessary if your body isn’t responding well to drugs, or if you have severe complications that require urgent treatment.

It’s most common to remove the entire rectum and colon if ulcerative colitis requires surgery, but more conservative approaches may also be considered.

Learn More About Treatment for Ulcerative Colitis

When it comes to food, there’s no known dietary cause of ulcerative colitis, but different foods may aggravate or help limit symptoms of the disease.

You’re more likely to need to change your diet during periods of active disease (flares), when eating soft, bland foods can help limit symptoms like cramping and diarrhea.

During flares, you may also want to avoid or limit high-fiber and high-fat foods, as well as caffeine, alcohol, dairy products, and spicy foods.

If you’re losing nutrients and water in your diet due to diarrhea, you may need to focus on increasing your fluid intake and getting enough calories, protein, vitamins, and minerals from foods or supplements.

Learn More About Diet and Ulcerative Colitis

People of European descent have a higher risk of developing ulcerative colitis than do those of African or Hispanic descent.

People of European Jewish descent have an especially high risk.

Ulcerative colitis tends to run in families, affecting men and women equally overall. But older men are more likely to develop it than older women, according to the Crohn’s and Colitis Foundation.

Ulcerative colitis is a type of inflammatory bowel disease (IBD), but it's not the same as irritable bowel syndrome (IBS).

Although the disorders share some of the same symptoms, such as abdominal pain and diarrhea, inflammation and ulcers do not occur with IBS.

Another disease often mentioned alongside ulcerative colitis is Crohn’s disease. Ulcerative colitis and Crohn’s are different types of IBDs that affect the digestive tract in different ways.

There are some common symptoms between the two conditions, but the overall pattern of symptoms tends to be different for each.

While diarrhea and rectal bleeding are more common in ulcerative colitis, Crohn’s disease more often causes severe abdominal pain, nausea, weight loss, and vomiting.

Ulcerative colitis is limited to the lining of the large intestine (colon), whereas Crohn’s disease can affect the entire digestive tract — from your mouth to your anus — and isn’t limited to the inner part of the intestines.

Learn More About the Differences Between UC and Crohn’s

The coronavirus pandemic has forced everyone to take extra precautions when it comes to health and safety. This is especially true for individuals with a compromised immune system. Although research shows that people living with UC are no more susceptible to catching the virus than the general population, organizations including the American College of Gastroenterology and the Crohn’s and Colitis Foundation have issued a number of new guidelines to help limit the spread of the infection. It’s also recommended that people with ulcerative colitis get the COVID-19 vaccine.

There are also a number of resources available to help people with UC manage these difficult times — from medication assistance to virtual therapy for mental health.

Learn More About Ulcerative Colitis and COVID-19

Additional reporting by Jordan M. Davidson.