Ulcerative Colitis

Ulcerative Colitis: Everything you need to know about symptoms, bowel examination, and the path to diagnosis

Are you living with abdominal pain, or have you experienced rectal bleeding? These can be signs of the chronic inflammatory bowel disease, ulcerative colitis. For many, talking about bowel habits feels like crossing a boundary, but an early bowel examination is crucial to regaining control of your life.

In this post, we review the most important signs of the disease and why a colonoscopy is the "gold standard" when a doctor needs to make a diagnosis.

What is ulcerative colitis?

Ulcerative colitis is an autoimmune condition that causes inflammation and ulcers in the lining of the large intestine (colon). The syndrome typically starts in the rectum and can spread upwards through the entire colon.

The most common symptoms include:

• Frequent and urgent need to have a bowel movement.
• Painful abdominal cramps.
• Rectal bleeding (often mixed with mucus).

Scientific focus: Research shows that early diagnosis and treatment ("treat-to-target") are crucial to avoiding long-term damage to the bowel and reducing the risk of colectomy (removal of the colon).

Source: Ungaro et al., Lancet, 2017

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Why is rectal bleeding a warning sign?

Although bleeding can be caused by harmless conditions such as haemorrhoids, in the case of ulcerative colitis, it is an indication that the lining of the bowel is so inflamed that ulcers have formed. If you experience blood in your stool along with changes in bowel habits for more than four weeks, you should always consult a doctor for a closer bowel examination.

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The Diagnosis: How is a colonoscopy performed?

When a doctor suspects bowel disease, a colonoscopy is the most accurate examination. Many fear the procedure, but it is performed under safe conditions, often with pain relief or sedative medication.

What happens during the examination?

1. Preparation: The bowel is emptied using a laxative the day before.
2. Endoscopy: A thin, flexible tube with a camera is inserted via the rectum.
3. Biopsies: The doctor takes small tissue samples of the mucosa. This is painless but essential for distinguishing ulcerative colitis from, for example, Crohn's disease or infections.

Why choose a colonoscopy?

It is the only method that allows the doctor to see the inflammation directly and assess its severity (often measured via the Mayo Score or UCEIS).

Scientific focus: Studies confirm that endoscopic assessment (colonoscopy) is the most reliable method for evaluating mucosal healing, which is the primary goal of modern treatment.

Source: Boal Carvalho et al., J Crohns Colitis, 2016

Moving forward after your bowel examination

If your colonoscopy shows signs of ulcerative colitis, the next step will be an individual treatment plan. Today, many effective treatments exist - from medical suppositories and foams to biological drugs that suppress the immune system.

Remember: You are not alone. By reacting to symptoms such as rectal bleeding early, you ensure the best conditions for a life with fewer limitations.

Treatment Strategy: From local treatment to advanced medicine

In Denmark, doctors follow a step-by-step strategy where the goal is always "steroid-free remission" - that is, a state where the bowel has healed without being dependent on corticosteroids.

Step 1: First-line treatment (5-ASA)

For most people with mild to moderate ulcerative colitis, the first step is 5-aminosalicylates (5-ASA), e.g., preparations such as Pentasa, Asacol, or Mezavant.

• Local treatment: If the inflammation is located at the bottom of the bowel, suppositories or foam are used.
• Systemic treatment: Tablets are used if the disease is more widespread. Often, the two are combined for maximum effect.

Step 2: Acute flare-ups (Corticosteroids)

For moderate to severe symptoms or a lack of effect from 5-ASA, corticosteroids (e.g., Prednisolone) are used. They work quickly and effectively on the inflammation, but due to side effects, they are only used for short periods to "put out the fire".

Step 3: Preventive immunomodulators

If the disease flares up every time steroid doses are tapered, Thiopurines (e.g., Imurel/Azathioprine) are often introduced. These agents help keep the immune system in check over the long term.

Scientific focus: Long-term studies show that Azathioprine is effective in maintaining remission but requires regular blood tests to monitor the liver and white blood cell counts.

Source: Timmer et al., Cochrane Database Syst Rev, 2016

Step 4: Biological medicine and "small molecules"

If the previous steps are not enough, the Danish healthcare system now offers advanced treatment. These are given either as an infusion (drip) at the hospital or as small injections under the skin at home.

Type	Examples of preparations (Denmark)	How does it work?
TNF inhibitors	Infliximab (Remsima), Adalimumab (Humira), Golimumab	Blocks a specific signaling substance (TNF) that creates inflammation.
Integrin inhibitors	Vedolizumab (Entyvio)	Works specifically in the gut by "locking the door" for white blood cells.
IL inhibitors	Ustekinumab (Stelara), Guselkumab	Blocks other signaling pathways (IL-12/23) in the immune system.
JAK inhibitors	Tofacitinib (Xeljanz), Upadacitinib (Rinvoq)	Tablet treatment that blocks enzyme processes inside the cells.

Scientific focus: The latest guidelines (2025) emphasize the importance of choosing biological treatment early ("early intervention") in patients at high risk of a more severe course, to prevent permanent damage to the bowel.

Source: ACG Clinical Guideline, 2025 / PubMed (Note: Updated versions are often referenced via the American College of Gastroenterology).

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Why is follow-up important?

Treatment in Denmark is currently highly personalised. Using stool samples (Calprotectin) and bowel examinations, the doctor can adjust your medication precisely according to how your bowel is doing - even if you feel healthy.

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See also

Inflammatory bowel disease - overview · Crohn's vs. ulcerative colitis