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The purpose of the Southern Cross Medical Library is to provide information of a general nature to help you better understand certain medical conditions. Always seek specific medical advice for treatment appropriate to you. This information is not intended to relate specifically to insurance or healthcare services provided by Southern Cross. For more articles go to the Medical Library index page.

Ulcerative colitis - causes, symptoms, treatment

Ulcerative colitis is a form of inflammatory bowel disease that causes swelling, ulceration and loss of function of the colon (large intestine) and rectum. Bloody diarrhoea and lower abdominal pain are the most common symptoms. 
Diagnosis of the disease normally requires endoscopic examination and biopsy tests. Ulcerative colitis is a chronic (long-term) condition that's likely to require ongoing treatment to address "flare-ups" (worsening of symptoms) and maintain periods of remission (absence of symptoms).
Ulcerative colitis is related to another type of inflammatory bowel disease - Crohn's disease.  Some of the symptoms are similar but, whereas it is primarily the large intestine and rectum that are affected by ulcerative colitis, Crohn's disease can develop in any part of the digestive tract.  Crohn's and ulcerative colitis are estimated to affect around 15,000 New Zealanders.


gastrointestinal tract
Ulcerative colitis can begin at any age but most commonly occurs in young adults between the ages of 15 and 25 years.  The condition also has an increased incidence between the ages of 50 and 70 years.  Children are rarely affected.  Women are more commonly affected by the condition than men. 


The exact cause of ulcerative colitis is unknown.  It has been hypothesised that it is an autoimmune disease in which the intestinal immune system attacks healthy intestinal cells and tissues.  Susceptibility to this abnormal behaviour of the intestinal immune system may be genetically inherited.  People who have a first-degree relative (i.e. brother, sister, child, parent) with ulcerative colitis are more likely to develop the disease.  In recent years approximately 30 genes that might increase susceptibility to the disease have been identified.  Environmental factors may also play a role.  Lifestyle factors such as stress and eating certain foods do not cause ulcerative colitis but may worsen the symptoms.

Signs and symptoms 

The most common symptoms of ulcerative colitis are episodes of bloody diarrhoea and pain in the lower abdomen. There may also be a sensation of urgent need to pass a bowel motion.  The bowel motions may be explosive and may contain mucous or pus. Other symptoms that may be experienced include:

  • Fatigue
  • Weakness
  • A general feeling of ill health
  • Weight loss
  • Loss of appetite
  • Bloating of the abdomen
Symptoms vary in frequency and severity. Approximately half of all sufferers will experience only mild symptoms. However for others, symptoms will be more severe. The severity of the symptoms tends to be related to how much of the colon is affected.

Ulcerative colitis is characterised by episodes where symptoms are problematic (“flare-ups”) and episodes where symptoms are absent (remissions).  Possible complications of ulcerative colitis include ulcers in the mouth, inflammation of the iris (eye), arthritis, skin lesions, blood clots, lactose intolerance and anaemia.

There is also an increased risk of bowel/colorectal cancer in patients who have had extensive ulcerative colitis for a number of years.


Ulcerative colitis may be suspected when a person has experienced symptoms of rectal bleeding, intermittent diarrhoea and abdominal pain.   As part of the diagnosis the doctor will take a full medical history and conduct a physical examination. The doctor may request that blood tests and specimens of the bowel motion (poo samples) are taken.

In ulcerative colitis, blood test results will often indicate anaemia and signs of inflammation in the body.  Samples of bowel motions will often indicate the presence of blood, pus and mucous.

If ulcerative colitis is suspected, endoscopy may be recommended. Endoscopy is the most important diagnostic test used to diagnose ulcerative colitis. During this test a small flexible tube (an endoscope) with a fibre-optic camera at its tip is passed into the rectum and colon.  The doctor is able to see the lining of the rectum and colon on a television screen and can look for signs of inflammation and ulceration that may indicate ulcerative colitis.  Small tissue samples (biopsies) from the lining of the colon and rectum can be taken for testing. Ulcerative colitis can be diagnosed by the characteristic abnormalities of this tissue.

Ulcerative colitis most commonly affects the rectum and the lower part of the colon (the sigmoid colon). 

X-ray tests using barium (a chalky liquid that is able to be seen on x-rays) can be helpful in determining how much of the colon is affected by ulcerative colitis.  The barium is administered into the rectum and colon via a tube inserted through the anus. A series of x-rays is taken, showing the outline of the inside of the colon and highlighting any abnormalities.


The aim of treatment is to reduce symptoms and prevent complications of the condition by reducing inflammation and maintaining periods of remission.  The type of treatment recommended will depend on the extent and severity of the condition. A person’s age, general health, lifestyle and personal choice will also be considered.
In very mild cases, diet changes and stress reduction may be all that are required to effectively manage symptoms. However, in severe cases, surgery to remove the colon and rectum may be required.  Treatment options include:
Stress reduction
While stress does not cause ulcerative colitis, it can worsen symptoms in some people. Developing techniques to reduce stress can be helpful in managing the condition.
There is no evidence to support any specific diet as a treatment for ulcerative colitis. Some foods, however, can worsen symptoms in some people. Keeping a food diary can be helpful in identifying which foods are problematic. Once identified, these foods should be avoided during flare-ups.  It may be recommended that vitamin and mineral supplements, such as iron and calcium, are added to the diet.

Alternative therapies
Some people have found that therapies such as massage, yoga, acupuncture and naturopathy have helped to manage their condition. It is advisable to discuss these with the doctor before starting them.

Treatment for ulcerative colitis usually involves the use of anti-inflammatory medications containing 5-aminosalicylic acid (5-ASA). Examples of these medications include sulfasalazine, mesalazine and olsalazine. These medications reduce inflammation in the colon and rectum leading to a reduction in symptoms. They are usually taken on a long-term basis and can help prevent flare-ups.

Severe flare-ups of ulcerative colitis may require hospitalisation. Corticosteroid medications, such as budesonide and prednisone may be required and can be given by mouth, through a drip (intravenously) or into the rectum (as an enema or suppository). Due to side effects, corticosteroids are not usually given long term.
Medications to suppress the immune system may be recommended and are often used in combination. Examples of these medications include azathioprine and cyclosporin. Infliximab, adalimumab and golimumab - new types of medication known as biologics that modify immune system function - are available for people with active ulcerative colitis whose symptoms are not adequately controlled with 5-ASA and corticosteroid medications.  However, use of these medications may be restricted by their high cost.

Dehydration caused by profuse diarrhoea may need to be treated by giving fluids through a drip. Medications to relieve pain and diarrhoea may also be given. Antibiotics may be required if infection is present in the colon.

Loss of blood through the rectum over a long period of time can lead to anaemia. Iron tablets may be prescribed to correct the anaemia and prevent its recurrence.  In cases of severe blood loss, blood transfusions may be required.

In severe cases, where medication and supportive treatment have not been successful in controlling the condition, or where the side effects of medications are intolerable, surgery may be required.  There are three main surgical techniques for the treatment of ulcerative colitis.

Total proctocolectomy and ileostomy involves removing the entire colon and rectum. The end of the small intestine is brought out onto the wall of the abdomen. A collection bag is placed over the opening and faecal matter will pass into it. The bag is emptied by the person as required. The ileostomy is permanent.  This type of surgery offers a permanent cure for ulcerative colitis.

Sub-total colectomy and ileorectal anastomosis is where most of the colon is removed, but the rectum is retained. The lower end of the small intestine is joined to the upper end of the rectum.

Ileoanal anastomosis (“Pouch operation”) involves removing the entire colon and rectum. A section of the small intestine is used to make a small pouch where faecal matter can be stored. The pouch is then attached to the anus. This surgical technique does not require a permanent ileostomy.

Support and information 

For further support and information get in touch with Crohn’s & Colitis New Zealand or visit their website. Crohn’s & Colitis New Zealand Charitable Trust
Free phone: 0800 ASK IBD (0800 275 423)


Basson, M.D. (2017). Ulcerative colitis (Web page). Medscape Drugs and Diseases. New York, NY: WebMD LLC. [Accessed: 02/08/17]
Crohn's & Colitis New Zealand (Date not stated). Ulcerative Colitis (Web Page). Wellington: Crohn's & Colitis New Zealand. [Date accessed: 02/08/17]
Mayo Clinic (2017). Ulcerative colitis (Web Page). Rochester, NY: Mayo Foundation for Medical Education and Research. [Accessed: 02/08/17]
Ministry of Health (2015). Inflammatory Bowel Disease. [Accessed 22/8/17]
Last Reviewed – August 2017


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