What to know about ulcerative colitis (UC)

Ulcerative colitis is a relatively common long-term condition that causes inflammation in the colon. Dietary changes and medications can often help manage symptoms, but surgery is an option in severe cases.

Ulcerative colitis (UC) is a form of inflammatory bowel disease (IBD) that is similar to Crohn’s disease.

The colon typically removes nutrients from undigested food and eliminates waste products through the rectum and anus as feces. However, UC causes ulcers to form on the lining of the colon. These ulcers may bleed and produce pus and mucus.

Various medication options can help reduce symptoms, and doctors can tailor treatment to meet individual needs.

In this article, we cover the symptoms, risk factors, and possible causes of UC, as well as some treatment options.

What is ulcerative colitis?

UC is a type of chronic IBD that causes inflammation and ulcers on the inside lining of the large intestine. Symptoms may vary depending on the area of inflammation.

People with UC may experience periods of worsening symptoms, known as flares, and periods when symptoms lessen or disappear, known as remission. Remission can last for months or years.

Symptoms of ulcerative colitis

The first symptom of UC is usually diarrhea.

Stools become progressively looser, and some people may experience abdominal pain with cramps and a severe urge to pass stool. Diarrhea may begin slowly or suddenly and occur with blood and mucus. Symptoms depend on the extent and spread of inflammation.

The symptoms of UC can include:

  • diarrhea
  • abdominal pain
  • bloody diarrhea with mucus
  • fatigue or tiredness
  • weight loss
  • loss of appetite
  • anemia
  • elevated temperature
  • dehydration
  • a constant urge to pass stool

Symptoms are often worse early in the morning.

Symptoms may be mild or absent for months or years at a time. However, if a person does not receive effective treatment, symptoms will usually return. Additionally, symptoms may vary depending on the part of the colon the condition affects.

Causes and risk factors of ulcerative colitis

The exact causes of UC are unclear. However, they may involve the following:

  • Genetic factors:
  •  suggest that people with UC are more likely to have certain genetic features. The specific genetic feature a person has may affect the age at which the disease appears.
  • Environmental factors: A person’s diet and exposure to air pollution or cigarette smoke may affect the onset of UC.
  • Immune system reaction: The body might respond to a viral or bacterial infection in a way that causes the inflammation associated with UC. Once the infection resolves, the immune system continues to respond, leading to ongoing inflammation.
  • Autoimmunity: Another theory suggests that UC may be an autoimmune condition. A fault in the immune system may cause it to fight nonexistent infections, leading to inflammation in the colon.
  • Gut microbiome: People with IBD tend to have differences in the bacteria, viruses, and fungi in their digestive tracts compared with people without IBD, though research is still ongoing to determine whether there is a connection.

Known risk factors for UC include:

  • Age: UC can affect people at any age but is more common at 15–30 years of age.
  • Ethnicity: White people and those of Ashkenazi Jewish descent have a higher risk of developing the condition.
  • Genetics: Although recent studies have identified specific genes that may play a role in UC, the link is unclear due to the role of environmental factors.

Types of ulcerative colitis

The sections below discuss the various types of UC, many of which affect different parts of the colon:

Ulcerative proctitis

This type affects only the end of the colon, or the rectum. Symptoms tend to include:

  • rectal bleeding, which may be the only symptom
  • rectal pain
  • an inability to pass stools despite frequent urges

Ulcerative proctitis is usually the mildest type of UC.


This type involves the rectum and the sigmoid colon, which is the lower end of the colon.

Symptoms include:

  • bloody diarrhea
  • abdominal cramps
  • abdominal pain
  • a constant urge to pass stool

Left-sided colitis

This type affects the rectum and the left side of the sigmoid and descending colon.

Symptoms usually include:

  • bloody diarrhea
  • abdominal cramping on the left side
  • weight loss


This type affects the whole colon. Symptoms include:

  • bloody diarrhea that is occasionally severe
  • abdominal pain and cramps
  • fatigue
  • considerable weight loss

Fulminant colitis

This is a rare, potentially life threatening form of colitis that affects the whole colon.

Symptoms tend to include severe pain and diarrhea, which can lead to dehydration and shock.

Fulminant colitis can present a risk of colon rupture and toxic megacolon, which causes the colon to become severely distended.

How is ulcerative colitis diagnosed?

A doctor will ask about a person’s symptoms and medical history. They will also ask whether any close relatives have had UC, IBD, or Crohn’s disease.

They will check for signs of anemia, or low iron levels in the blood, and tenderness around the abdomen.

Several tests can help rule out other possible conditions and diseases, including Crohn’s disease, infections, and irritable bowel syndrome.

Possible tests include:

  • blood tests
  • stool tests
  • X-ray
  • barium enema, during which a healthcare professional passes a fluid called barium through the colon to make any changes or anomalies visible on a scan
  • sigmoidoscopy, in which a healthcare professional inserts an endoscope — a flexible tube with a camera at the end — into the rectum
  • colonoscopy, in which a doctor examines the whole colon using an endoscope
  • CT scan of the abdomen or pelvis

A person with UC will need to see a gastroenterologist, a doctor who specializes in treating conditions of the digestive system.

The doctor can assess the type and severity of the condition and create a treatment plan.


According to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), some dietary measures may help relieve symptoms, including:

  • eating smaller, more frequent meals, such as five or six small meals per day
  • drinking plenty of fluids, especially water, to prevent dehydration
  • avoiding caffeine and alcohol, which can both increase diarrhea
  • avoiding sodas, which can increase gas
  • keeping a food diary to identify foods that make symptoms worse

Depending on a person’s symptoms, a doctor may suggest temporarily following a specific diet such as:

  • a low fiber diet
  • a lactose-free diet
  • a low fat diet
  • a low salt diet

What’s the best diet for ulcerative colitis?

If a person is experiencing symptoms of UC, a doctor may recommend a low residue or low fiber diet to reduce the amount of stool a person passes. This diet can include:

  • refined grains such as white bread and white rice
  • cooked vegetables with the peel, seeds, and stalks removed
  • eggs
  • lean meat and fish
  • certain fruits, such as peeled apples and ripe bananas

A person with UC should discuss any dietary changes with a healthcare professional in advance.

How can a person prevent or stop ulcerative colitis flares?

A person may be able to avoid or delay UC flares by carefully monitoring their symptoms, diet, and environmental exposures and limiting their exposure to potential triggers.

What triggers ulcerative colitis?

Individuals can have different triggers for a UC flare. Common triggers include:

  • use of nonsteroidal anti-inflammatory drugs (NSAIDs)
  • stress
  • exposure to air pollution or cigarette smoke
  • dietary intolerances, such as dairy or lactose

FAQ around ulcerative colitis

The following sections answer some common questions about UC.

Does ulcerative colitis ever go away?

UC is a chronic condition that currently has no cure. However, treatment can help a person enter a period of remission and prevent or delay future flares.

Can I give my kids ulcerative colitis?

Some genetic factors that pass from parents to children can increase a person’s risk of developing UC. However, the condition’s onset typically involves a combination of genetic and environmental factors.

What is the life expectancy with ulcerative colitis?

The life expectancy of a person with UC is similar to that of a person without the condition. Effective treatment can help prevent flares and life threatening complications.

How often do I need a colonoscopy?

The Crohn’s and Colitis Foundation recommends that people who have had UC for at least 8 years get a colonoscopy every 1–2 years. Other risk factors may affect how often a person needs to have a colonoscopy.

Does ulcerative colitis make you immunocompromised?

UC affects the immune system. Treatment for UC can include medications that suppress an overactive immune system, which can cause a person’s immune system to be compromised.


The outlook for UC varies widely. While it is a lifelong condition, the overall mortality rate for people with UC is the same as for people without it.

However, some UC complications, such as toxic megacolon, can be life threatening. In addition, at least 5% of people with UC develop colon cancer, and this risk increases over time.

UC involves periods of remission, during which symptoms improve, and flares, during which symptoms worsen. Some people may experience remission all year and have few or no symptoms, while others may experience at least one flare at some time during the year.