Page last reviewed: 13/07/2011

Ulcerative colitis is a long-term (chronic) condition affecting the colon. Symptoms of ulcerative colitis include:

  • bloody diarrhoea
  • abdominal pain
  • a frequent need to go to the toilet
  • weight loss

The colon

The colon, also known as the large intestine, absorbs nutrients from undigested food and passes out waste products through the rectum and anus in stools (faeces).

Ulcerative colitis causes the colon to become inflamed (swollen) and in severe cases, ulcers (painful sores) may form on the lining of the colon. These ulcers can bleed and produce mucus and pus.

Symptoms of ulcerative colitis can range from mild to severe, with the condition being very unpredictable. Symptoms can flare up and then disappear (go into remission) for months or even years.

At its most severe, the entire colon can become inflamed (known as pancolitis). This form of ulcerative colitis is particularly challenging to treat.

The causes for the condition are unknown, though research suggests that both environmental and genetic factors are involved.

How common is ulcerative colitis?

Ulcerative colitis is an uncommon condition. It is estimated that there are ten new cases a year out of every 100,000 people. There are currently 100,000 people in England with ulcerative colitis.

The condition normally appears between the ages of 15 and 30. The condition is more common in white people of European descent, especially those descended from Ashkenazi Jewish communities (Jews who lived in Eastern Europe and Russia) and black people. The condition is much rarer in people of Asian background. The reasons for this are unclear.

Both sexes seem to be affected equally by ulcerative colitis.


The outlook for most people with ulcerative colitis is usually quite good. Symptoms are often mild to moderate and can usually be controlled using medication.

However, an estimated one in five people with ulcerative colitis have severe symptoms that often respond less well to medication. In these cases, it may be necessary to surgically remove the colon.

Chronic usually means a condition that continues for a long time or keeps coming back.
The anus is the opening at the end of the digestive system where solid waste leaves the body.
Stool (also known as faeces) is the solid waste matter that is passed from the body as a bowel movement.
Inflammation is the body's response to infection, irritation or injury, which causes redness, swelling, pain and sometimes a feeling of heat in the affected area.
A disease is an illness or condition that interferes with normal body functions.
An ulcer is a sore break in the skin, or on the inside lining of the body.
Pain is an unpleasant physical or emotional feeling that your body produces as a warning sign that it has been damaged.
Remission is when the symptoms of a condition are reduced (partial remission) or go away completely (complete remission).
Genetic is a term that refers to genes- the characteristics inherited from a family member.


Conditions that cause inflammation of the intestines, such as ulcerative colitis or Crohn's disease, are known as inflammatory bowel disease (IBD). This should not be confused with irritable bowel syndrome (IBS), which is a different condition and requires different treatment.

Page last reviewed: 13/07/2011

The symptoms of the condition can vary, depending on how much of the colon is affected and the level of inflammation.

Common symptoms include

  • abdominal pain,
  • bloody diarrhoea with mucus

There may also be

  • tiredness and fatigue
  • loss of appetite and weight loss
  • anaemia
  • fever
  • dehydration
  • weight-loss
  • a constant desire to empty the bowels (known as tenesmus)

Symptoms are often worse first thing in the morning.

Many people living with the condition will have longs periods of months or years where they experience very few, or no, symptoms. However, in all cases, without treatment symptoms will eventually return.

No specific trigger that causes the return of symptoms has been identified, though it is thought that stress may play a factor.


Acute means occurring suddenly or over a short period of time.
Diarrhoea is the passing of frequent watery stools when you go to the toilet.
Loss of appetite
Loss of appetite is when you do not feel hungry or want to eat.
A high temperature, also known as a fever, is when someone's body temperature goes above the normal 37°C (98.6°F).
Pain is an unpleasant physical or emotional feeling that your body produces as a warning sign that it has been damaged.
Fatigue is extreme tiredness and lack of energy.
Dehydration is an excessive loss of fluids and minerals from the body.

Page last reviewed: 13/07/2011

The exact cause of the condition is unknown, but researchers believe there are a number of factors involved. These are listed below.


It seems that the genes you inherit from your parents play a role in developing ulcerative colitis. Studies have shown that around 16% of people with ulcerative colitis have a close relative with the condition. Also, levels of ulcerative colitis are a lot higher in certain ethnic groups than in others.

Researchers have identified a number of possible genes that seem to make people more vulnerable to developing ulcerative colitis, though exactly how they do this is still uncertain.


Where and how we live also seems to play a role in the development of ulcerative colitis. The condition is much more common in certain parts of the world - namely, urban areas in northern parts of Western Europe and America.

A number of environmental factors have been suggested, including.

  • air pollution
  • diet - the typical Western diet is high in carbohydrates and fats, which may explain why Asian people, who tend to eat a diet lower in carbohydrates and fats, are less affected by ulcerative colitis
  • hygiene - children are being brought up in increasingly germ-free environments, but it is possible that the immune system requires exposure to germs to develop properly (this is known as the hygiene hypothesis, and has also been suggested as a possible cause for the rise in allergic conditions such as asthma)

However, no factors have been positively identified.

Immune system

Some researchers believe that a viral or bacterial infection triggers our body's natural defence system against infection, the immune system.

The immune system responds to the infection by causing the inflammation associated with ulcerative colitis, but for some reason the immune system does not 'turn off' once the infection has passed, and continues to cause inflammation.

Other scientists think that no infection is involved and the immune system just malfunctions by itself.

A leading theory is that the immune system mistakes the 'friendly bacteria' found in the colon (which aid digestion) as an infection. So it tries to halt the spread of what it thinks is an infection by causing inflammation (swelling) of the colon. (Conditions where the immune system attacks healthy tissue are known as autoimmune conditions).

Page last reviewed: 13/07/2011

Your GP will first ask you about your symptoms, your general health and your medical history. Then they will physically examine you, checking for signs such as paleness (caused by anaemia) and tenderness in the stomach (caused by inflammation.)

The next step is to test your blood and a sample of your stool. Blood tests can show whether you have anaemia. Also there are two specialised blood tests known as the erythrocyte sedimentation rate (ESR) test and the C reactive protein (CRP) test. These tests look for tell-tale changes in the blood that point to the presence of disease and inflammation. Your stools will be checked for infection. X-rays may also be taken to help assess the extent of the condition.


The diagnosis will then need to be confirmed by directly examining the level and extent of the inflammation of the bowel. This is initially done by using a sigmoidoscope - a flexible tube containing a camera that is inserted into your rectum.

The procedure is not painful, though you may be given a sedative to relax you. The procedure typically takes around 15 minutes, after which you can go home.

The sigmoidoscope is only capable of looking at the rectum and lower part of the colon. If it is thought that your ulcerative colitis has affected more of your colon than that, another examination will be required. This is known as a colonoscopy.


A colonoscopy uses a longer and more flexible tube called the colonscope, which allows your entire colon to be examined.

Before having the examination it will be necessary for your colon to be entirely empty. Therefore you will be required to take some strong laxatives before the examination.

Again, the procedure is not painful though you may feel some initial discomfort. You will be given sedatives to help you relax. The procedure takes around half an hour, after which you can go home.


An ulcer is a sore break in the skin, or on the inside lining of the body.
Blood tests
During a blood test, a sample of blood is taken from a vein using a needle, so it can be examined in a laboratory.
An X-ray is a painless way of producing pictures of inside the body using radiation.
An enema is an injection of fluid into the large intestine / colon to empty the bowel. It can also be used to make the bowels show up more clearly in an X-ray.
Inflammation is the body's response to infection, irritation or injury, which causes redness, swelling, pain and sometimes a feeling of heat in the affected area.
Stool (also known as faeces) is the solid waste matter that is passed from the body as a bowel movement.
A biopsy is a test that involves taking a small sample of tissue from the body so it can be examined.
The anus is the opening at the end of the digestive system where solid waste leaves the body.

Page last reviewed: 13/07/2011

Once the diagnosis is confirmed, you may then be referred to a gastroenterologist (doctor who specialises in conditions of the digestive system) so the severity of your condition can be assessed and a treatment plan drawn up.

The severity of the condition is judged using a number of factors, including:

  • how many times you are passing stools
  • whether those stools are bloody
  • whether you have symptoms of fever
  • how much control you have over your bladder
    your general wellbeing

Mild to moderate cases can be treated on an outpatient basis (meaning treatment can be carried out through a series of appointments at a hospital or clinic) or at home. More severe cases will require admission to hospital.

There are two types of treatment:

  • managing active ulcerative colitis - treating the symptoms until they go into remission
  • maintaining remission - using treatment to prevent the return of symptoms

Managing active ulcerative colitis

There are three main types of medicines that are used to manage active ulcerative colitis: aminosalicylates, steroids and immunosuppressants.


Aminosalicylates are the first treatment option for mild to moderate ulcerative colitis. They help reduce inflammation and can be taken:

  • orally - as a tablet
  • as a suppository - a capsule that you insert into your rectum, where it then dissolves
  • through an enema - where fluid is pumped into your colon

How the aminosalicylates are administered will depend on the severity and extent of your condition.

Mild forms may only require oral and topical aminosalicylates. A more serious form of the condition that involves the entire colon may require a combination of oral aminosalicylates and an enema. This is because a suppository can only reach certain parts of the colon.

Side effects of aminosalicylates include:

  • diarrhoea
  • nausea
  • headaches
  • skin rashes 


If your ulcerative colitis is more severe or is not responding to the aminosalicylates, then steroids may be used. Steroids act much like aminosalicylates in reducing inflammation, except they are a lot stronger.

As with aminosalicylates, steroids can be administered orally, topically or through a suppository or enema.

Long-term use of steroids, especially oral steroids, is not recommended as they can cause potentially serious side effects. Therefore, once your colitis responds to treatment, it is likely you will need to stop using them.

Side effects of short-term steroid use include:

  • changes in the skin such as acne
  • sleep and mood disturbance
  • indigestion
  • swelling

Side effects of prolonged steroid use (more than 12 weeks) include:

  • osteoporosis (fragile bones)
  • high blood pressure (hypertension)
  • diabetes
  • weight gain
  • cataracts and glaucoma (both disorders of the eye)
  • thinning of the skin
  • easy bruising
  • muscle weakness

To minimise the risk of prolonged steroid use, you should:

  • eat a healthy and balanced diet with plenty of calcium
  • maintain a healthy body weight
  • stop smoking
  • not drink more than the safe limits of alcohol (the recommended daily levels are three to four units of alcohol for men and two to three units for women)
  • take regular exercise

You will also require regular appointments to check for high blood pressure, diabetes and osteoporosis if your treatment requires long-term use of steroids.


If your condition is still not responding to treatment, you may be given immunosuppressants, sometimes in combination with other medicines. You may also be given them if it is decided to withdraw your steroid treatment to reduce possible side effects.

Immunosuppressants work by reducing or suppressing your body's immune system. This will then stop the inflammation caused by ulcerative colitis.

Iimmunosuppressants can take a while to start working - typically two to three months.

The drawback of immunosuppressants is that they are non-specific - meaning they will not just affect your colon, but your whole body. This may make you more prone to infection, so it is important to report any signs of infection, such as inflammation, fever or nausea, promptly to your GP.

They can also lower the production of red blood cells, making you prone to anaemia. You will require regular blood tests to monitor your levels of blood cells and check for the presence of any other problems.

The preferred immunosuppressant used in the treatment of ulcerative colitis is a medicine known as azathioprine. This is because it causes no side effects in most people.

Possible side effects of taking azathioprine include:

  • nausea
  • diarrhoea
  • liver damage
  • anaemia
  • increased risk of infection
  • increased risk of bruising

Long-term use of azathioprine has been linked to a small increase in the risk of cancer, particularly skin cancer. If you need to take azathioprine for several years, you may wish to minimize the risk by avoiding strong sunlight and using appropriate ultra-violet (UV) protection, such as sunblock.

Azathioprine is not normally recommended for pregnant women. However, if it is the only treatment that successfully controls your condition, it is likely you will be advised to continue taking it. Any risk to you or your child is far outweighed by the risks presented by ulcerative colitis.

Managing severe active ulcerative colitis

Severe active ulcerative colitis will need to be managed at hospital. This is because severe colitis could put you at risk of dehydration, malnutrition and potentially fatal complications such as your colon rupturing (splitting).

You will be given intravenous (injected directly into your vein) fluid to treat dehydration. The condition itself can be treated using injections of steroids and/or immunosuppressants.


Infliximab is a new type of medication that is only used to treat severe active ulcerative colitis if you are unable to take steroid medication for medical reasons, such as being allergic to it.

It works by targeting a protein called TNF-alpha, which the immune system uses to stimulate inflammation.

Infliximab is given through a drip in your arm over the course of two hours. This is known as an infusion.

You will be given further infusions after two weeks and again after six weeks. Infusions are then given every eight weeks, if treatment is still required.

Around one in four people have an allergic reaction to infliximab and experience symptoms such as:

  • joint and muscle pain
  • itchy skin
  • high temperature
  • rash
  • swelling of the hands and/or lips
  • problems swallowing
  • headaches

Symptoms can range from mild to severe and they usually develop in the first two hours after the infusion has finished. Rarely, people have experienced a delayed allergic reaction days or even weeks after an infusion. If you begin to experience the symptoms listed above after having infliximab, seek immediate medical assistance.

Due to the significant (one in four) risk of having a severe allergic reaction, your health will be carefully monitored after your first infusion and, if necessary, powerful anti-allergy medication, such as epinephrine, may be used.

There have been a number of cases where infliximab has 'reactivated' a previously dormant tuberculosis (TB) infection. Therefore, it may not be suitable if you have a previous history of TB. The same is also true with the viral infection hepatitis B.

Infliximab is also not recommended for people with a history of heart disease.

Infliximab will make you more vulnerable to infection, so you should avoid contact with people who have a known chickenpox or shingles infection.

You should report any symptoms of a possible infection, such as coughs, a high temperature or a sore throat, to your GP.

Maintaining remission

Once the symptoms are in remission, taking a regular dose of aminosalicylates should help prevent the symptoms reoccurring.

If the condition does reoccur on a frequent basis, a regular dose of an immunosuppressant such as azathioprine may be recommended.

If your ulcerative colitis was extensive, a lifelong maintenance therapy is normally recommended. If your ulcerative colitis was limited to a small part of your colon, you may be able to stop therapy, if two years pass without a return of symptoms.


If ulcerative colitis does not respond to intensive medical treatment, then surgery may be required.
You may also wish to consider surgery if your maintenance therapy is not working and the condition is affecting your quality of life.

Surgery involves permanently removing the colon - a colectomy. As part of the operation, your small intenstine will have to be re-routed from the colon so it can pass waste products out of your body.

This used to be achieved by carrying out an ileostomy, where an incision is made in your stomach and the small intestine is pulled slightly out of the hole and connected to a pouch (which collects waste materials).

However, in recent years, another technique known as the ileo-anal pouch has been increasingly preferred. This is an internal pouch constructed by the surgeon out of the small intestines and then connected to the muscles surrounding your anus. The pouch can be emptied in much the same way as when you defecate.

The advantage of this technique is that you are not required to carry an external pouch.


Other treatments

Nicotine patches

As smokers have less chance of developing ulcerative colitis, some researchers have tried using nicotine patches to relieve the symptoms. 

While they were of some benefit, studies have shown that conventional medicines are far more effective and most experts would not recommend nicotine patches as a routine treatment. 

Omega-3 fish oil

Some research has been carried out to see if omega-3 fish oil proved effective in treating the condition. No benefit could be found.


There has been limited research into whether probiotics could help achieve remission of the symptoms of ulcerative colitis. While the results of the research were positive, the trials looking at the treatment were relatively small and further research is required to confirm the results.

Probiotics are so-called friendly bacteria that are available in capsule, liquid and powder form.

Some probiotics may not be suitable if you are taking immunosuppressants as they could cause a serious infection. Check with your GP if you are currently taking probiotics and are thinking of trying immunosuppressants.


Acute means occurring suddenly or over a short period of time.
An enema is an injection of fluid into the large intestine / colon to empty the bowel. It can also be used to make the bowels show up more clearly in an X-ray.
Corticosteroid is a naturally occurring hormone produced by the adrenal gland, or a synthetic hormone having similar properties. It is used to reduce inflammation, so reducing swelling and pain.
Remission is when the symptoms of a condition are reduced (partial remission) or go away completely (complete remission).
Antidiarrhoeal medicine is used to treat diarrhoea. For example, dicyclomine.
Inflammation is the body's response to infection, irritation or injury, which causes redness, swelling, pain and sometimes a feeling of heat in the affected area.
Intravenous (IV) means the injection of blood, drugs or fluids into the bloodstream through a vein.

Low-residue diet

There is evidence that eating a low-residue diet can sometimes help improve symptoms during a flare-up.

A low-residue diet is a diet that is designed to reduce the amount and frequency of the stools you pass.

Foods that can be eaten as part of a low-residue diet include:

  • enriched refined white bread
  • breakfast cereals such as cornflakes
  • white rice
  • refined pasta
  • noodles
  • cooked vegetables
  • lean meat and fish
  • eggs


Page last reviewed: 13/07/2011

Treatment Pros Cons
Anti-inflammatory drugs

Aminosalicylates including mesalazine, sulfasalazine, balsalazide and olsalazine. Can be taken as tablets, foam enema or suppository


  • Reduce inflammation 
  • Maintain remission


  • Risk of rare blood condition
  • Can cause diarrhoea, nausea, headache, abdominal pain and rashes
Steroids (also known as corticosteroids), including budesonide, hydrocortisone and beclometasone dipropionate. Can be taken as tablets, foam enema or suppository
  • Quickly reduce inflammation in the intestines
  • Not usually used for maintenance as they can have harmful side effects, such as osteoporosis, when used long term in high doses
  • Need to be under the care of a specialist
  • Can cause changes in the skin such as acne, sleep and mood disturbance, indigestion, swelling
Immunosuppressant drugs
Azathioprine and mercaptopurine are drugs that suppress the immune system (thiopurines). Can be taken as tablets
  • Reduce inflammation in the gut by reducing the immune response
  • Make you more prone to infection
  • Regular blood and liver tests are needed 
  • Need to be under the care of a specialist 
  • Can take up to 12 weeks to work
  • Can cause flu-like symptoms, such as aching, headache and diarrhoea, nausea and vomiting and decrease in bone marrow
Immunosuppressant drugs
Infliximab TNF-alpha inhibitor, which modulates the body's immune response and can reduce inflammation
  • Can reduce inflammation

  • Can only be used by certain patients (NICE recommendation)
  • Need to be under the care of a specialist
  • Can cause headache, dizziness and nausea
Surgery: removal of the colon and rectum
In a procedure called colectomy and end ileostomy, the whole of the colon and the rectum are removed
  • This can cure the condition
  • An ileostomy is formed, and waste products leaving the body are collected in a bag via a stoma (an opening created in the abdomen)
Surgery: creation of an internal pouch
This is usually done at a later operation when the rectum is removed and an internal pouch is created using the final section of the small intestine which is joined to the back passage.
  • The internal pouch can store waste materials, which can then be expelled in the normal way
  • Risk of infertility in women
  • Can be followed by pouchitis (inflammation of the internal pouch)

Page last reviewed: 13/07/2011

Primary sclerosing cholangitis

Primary sclerosis cholangitis (PSC) is a common complication of ulcerative colitis that affects about 1 in every 20 people with the condition.

PSC is where the bile ducts, which are small tubes that are used to transport bile (digestive juice) out of the liver and into the digestive system, become progressively inflamed and damaged over time.

PSC does not usually cause any symptoms until the condition has progressed to an advanced stage. Symptoms can include:

  • fatigue (extreme tiredness)
  • diarrhoea (loose, watery stools)
  • itchy skin
  • weight loss
  • chills
  • high temperature (fever) of 38C (100.4F) or above
  • jaundice - yellowing of the skin and the whites of the eyes

There is no direct treatment for PSC but medication can be used to relieve many of the symptoms, such as itchy skin.

Bowel cancer

People who have ulcerative colitis have an increased risk of developing bowel cancer (cancer of the colon, rectum or bowel), especially if the condition is severe or extensive.

The longer you have ulcerative colitis, the greater the risk is:

  • after 10 years the risk of developing bowel cancer is 2%
  • after 20 years the risk of developing bowel cancer is 8%
  • after 30 years the risk of developing bowel cancer is 18%

You will probably be advised to have a colonoscopy every few years to check that no cancer has developed. The frequency of the colonoscopy examinations will increase the longer you live with the condition.

To reduce the risk of developing bowel cancer, you should eat a healthy, balanced diet including plenty of fresh fruit and vegetables. It is also important to take regular exercise, maintain a healthy weight and avoid alcohol and smoking.

Taking your aminosalicylates as prescribed should also help to reduce your risk of bowel cancer.


Osteoporosis is a common complication affecting an estimated 15% of people with ulcerative colitis.

Osteoporosis is a condition that affects the bones, causing them to become thin and weak. The condition is not directly caused by ulcerative colitis, but develops as a side effect of prolonged steroid use.

Though the risks associated with steroid use are well known, in some people, long-term use of steroids is the only way to control the symptoms of ulcerative colitis.

There are a number of medications, such as bisphosphonates, that can be used to strengthen the bones.

You may also be advised to take regular supplements of vitamin D and calcium, as both of these substances have bone-strengthening effects.

Toxic megacolon

Toxic megacolon is a rare and serious complication that occurs in approximately 5% of cases of severe ulcerative colitis. In severe cases of inflammation, gases can get trapped in the colon, causing it to swell. This is dangerous as it can send the body into shock (a sudden drop in blood pressure), can rupture (split) the colon and can cause infection in the blood (septicaemia).

The symptoms of a toxic megacolon include:

  • abdominal pain
  • dehydration
  • high body temperature (40C or 104F)
  • a rapid heart rate

Toxic megacolon can be treated with intravenous fluids, antibiotics and steroids. At the same time, a tube will need to be inserted into your rectum and colon so the gas can be drawn out and your colon decompressed.

In more severe cases, a colectomy will need to be performed.

Promptly treating any symptoms of ulcerative colitis before they become severe can help prevent a toxic megacolon from developing.


Joints are the connection point between two bones that allow movement.
The immune system is the body's defence system, which helps protect it from disease, bacteria and viruses.
An ulcer is a sore break in the skin, or on the inside lining of the body.
Pain is an unpleasant physical or emotional feeling that your body produces as a warning sign that it has been damaged.
The liver is the largest organ in the body. Its main jobs are to secrete bile (to help digestion), detoxify the blood and change food into energy.
Inflammation is the body's response to infection, irritation or injury, which causes redness, swelling, pain and sometimes a feeling of heat in the affected area.
If you have a deficiency it means you are lacking in a particular substance needed by the body.
Blood supplies oxygen to the body and removes carbon dioxide. It is pumped around the body by the heart.

Page last reviewed: 13/07/2011


Although diet does not seem to play a role in causing ulcerative colitis, it can help control the condition.

The following advice may help:

  • Keep a food diary - you may find you can tolerate some foods, while others will make your symptoms worse. By keeping a record of what and when you eat, you should be able to eliminate problem foods from your diet.
  • Eat small meals - eating five or six smaller meals a day, rather then three main meals, may make you feel better.
  • Drink plenty of fluids - it is easy to become dehydrated when you have ulcerative colitis, as you can lose a lot of fluid through diarrhoea. Water is the best source of fluids. Avoid caffeine and alcohol as these will make your diarrhoea worse, and fizzy drinks as these will cause gas.
  • Food supplements - you should ask your GP or gastroenterologist whether you need any food supplements, as you might not be absorbing enough vitamins and minerals, such as calcium and iron.


Again, although stress does not cause ulcerative colitis, successfully managing your stress levels may reduce the frequency of symptoms. The following advice may help:

  • Exercise - exercise has been proven to reduce stress and lift your mood. Your GP or gastroenterologist should be able to advise you on a suitable exercise plan.
  • Relaxation techniques - breathing exercises, meditation and Yoga are good ways of teaching yourself to relax.
  • Communication - living with ulcerative colitis can be frustrating and isolating. Talking to other people with the condition can be of great benefit.


Content provided by NHS Choices and adapted for Ireland by the Health A-Z.

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