Ulcerative colitis is a chronic condition that develops over several stages, including mild, moderate, and severe.

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Ulcerative colitis (UC) is a common type of inflammatory bowel disease. UC may develop over a series of exacerbations, or flares, and remissions, meaning its symptoms may improve and decline.

The condition causes inflammation and deterioration of the colonic wall, resulting in bloody diarrhea, which may also occur with mucus. The severity of the symptoms depends on whether a person’s condition is at a mild, moderate, or severe stage.

This article looks at the stages of UC, its symptoms, complications, treatments, and frequently asked questions.

There are three main stages to UC. The classification depends on rectal bleeding, including:

  • mild — fewer than four episodes per day
  • moderate — more than four episodes per day
  • severe — more than six episodes per day

A fourth category is fulminant UC, a subset of the disease that causes severe signs and symptoms with sudden onset, including:

  • frequent bloody stools
  • weight loss
  • high fever
  • abdominal tenderness

These symptoms, without treatment, may result in hospitalization.

Specific symptom progression

Most rectal symptoms develop within the first year of having UC.

With severe UC, there may also be features suggesting the condition affects other areas of the body. At this point, the person may also be showing signs of hypoalbuminemia, where there is insufficient albumin protein in the blood.

Symptoms of UC increase in severity with each stage of the disease. Symptoms that increase as the disease progresses can include the following:

In severe cases, UC can cause symptoms in parts of the body outside the intestines, called extraintestinal manifestations. These symptoms can include:

UC is a chronic condition that can cause complications throughout a person’s lifetime as the disease increases and decreases in severity.

Common symptoms of mild or moderate UC can contribute to malnutrition and weight loss, including:

  • Diarrhea: This can cause dehydration, which means the body is low in fluids, nutrients, and necessary electrolytes such as:
  • Abdominal pain and nausea: These symptoms can reduce a person’s appetite, making it difficult for someone to consume enough calories and sufficient nutrients.
  • Rectal bleeding: This bleeding can lead to iron deficiency anemia.
  • Frequent bowel movements: These movements may cause a person to eat less to avoid diarrhea, putting a person at risk of becoming malnourished.

More severe complications that can occur throughout the stages of UC, but particularly at later stages, include:

While there is no cure for UC, there are treatments available.

Some treatments span multiple stages of UC, including:

  • oral aminosalicylates, such as mesalamine or sulfasalazine
  • topical aminosalicylates
  • corticosteroids
  • immunomodulators
  • antimetabolites

Learn more about UC-approved drugs.

The following table shows treatments for UC according to the specific stage.

mildoral aminosalicylates, or 5-ASA
enema with 5-ASA
moderateoral 5-ASA
enema with 5-ASA
oral glucocorticoids
enema with glucocorticoids
severeoral 5-ASA
enema with 5-ASA
oral or IV glucocorticoids
enema with glucocorticoids
fulminantIV glucocorticoids
IV cyclosporine

Below are some frequently asked questions on UC.

How fast does UC progress?

UC usually develops gradually. However, the onset can also be very rapid, particularly in the case of fulminant UC.

How long do symptoms of UC typically last?

The duration of UC exacerbations varies from days to months.

How do doctors determine the stage or severity of UC?

Doctors grade the severity of UC according to rectal bleeding. Factors that determine the stage can vary slightly according to different criteria.

What is the most common age to receive a diagnosis of UC?

There are two peak ages when UC may develop. The most common age for someone to receive a diagnosis is between 15 and 30 years, but the likelihood increases again between 50 and 70 years of age.

How do flares of UC vary between mild, moderate, and severe cases?

UC symptom exacerbations typically worsen with each stage, with severe cases causing the most significant symptoms and complications.

UC is a chronic condition that may have periods of flares and remissions. The main indications of UC are bloody diarrhea and abdominal pain.

There are different criteria that a doctor may use to identify the stage of UC. However, the stage usually depends on how many bleeding episodes a person has in a day.

The main stages of UC are mild, moderate, severe, and fulminant. Fulminant UC is a subset of the condition that causes sudden and severe symptoms.

UC is not curable with medication, but treatments can reduce the frequency and severity of flares specific to the stage.