Collagenous Colitis And Lymphocytic Colitis

Overview

Collagenous colitis and lymphocytic colitis are two types of a condition called 'microscopic colitis'. They cause inflammation (swelling and irritation) of the inner lining of the colon — the large bowel. The word 'microscopic' is used because when a doctor looks inside the bowel with a camera, the lining usually looks completely normal. The changes can only be seen when tiny tissue samples are looked at under a microscope. In collagenous colitis, a thick band of a protein called collagen builds up under the surface of the bowel lining. In lymphocytic colitis, extra white blood cells called lymphocytes gather there. Apart from what the microscope shows, the two conditions cause the same main symptom: long-lasting, watery diarrhoea (loose, runny stools). They are not the same as ulcerative colitis or Crohn's disease, and they do not usually cause lasting damage to the bowel.

It is more common than doctors once thought. Among people who are checked for ongoing diarrhoea, microscopic colitis is found in a meaningful share of cases — especially in older adults. Because the bowel looks normal on a camera test, it is easy to miss unless tissue samples (biopsies) are taken.

It mostly affects adults over the age of about 50 to 60, though younger adults and, rarely, children can have it. Women are affected more often than men. It is also more likely in people who have other immune-related conditions such as coeliac disease, thyroid problems or rheumatoid arthritis, and in people who take certain long-term medicines.

Symptoms

Common symptoms

• Watery, loose stools (diarrhoea) that keep going for weeks or months, not just a day or two
• Needing to go to the toilet suddenly and urgently — sometimes called 'faecal urgency'
• Going several times a day, and sometimes at night
• Mild cramping or aching tummy pain
• Bloating, wind and a gurgling feeling in the belly
• Losing a little weight without trying
• Feeling very tired or drained
• Sometimes accidentally leaking stool (incontinence), especially if a toilet is not close by
• Feeling sick or having a poor appetite
• Stools are usually watery and do not contain blood — blood is not typical and should always be checked

Symptoms in children

• This condition is rare in children, so other causes are usually looked at first
• Long-lasting loose stools
• Tummy pain and bloating
• Poor weight gain or slower growth than expected
• Tiredness and low energy
• A child with ongoing diarrhoea should always be seen by a doctor

Symptoms in older adults

• Diarrhoea can lead to dehydration (losing too much water and salt) more quickly, which can cause confusion or dizziness
• Tiredness and weakness, which can increase the risk of falls
• Weight loss and poor appetite, sometimes leading to low vitamin levels
• Symptoms can be confused with side effects of other medicines, so a medicine review is helpful
• Needing to be near a toilet can affect confidence and independence
• Frail or housebound people may need extra support to stay well hydrated

Causes

Main causes

• The exact cause is not known. It is thought to be an abnormal immune reaction in the lining of the colon, where the body's defence system mistakenly reacts to something in the bowel.
• In collagenous colitis, this reaction leads to a thick band of collagen forming under the surface of the bowel lining.
• In lymphocytic colitis, the reaction leads to a build-up of white blood cells called lymphocytes in the lining.
• Certain medicines are linked to triggering or worsening it, including some painkillers, some stomach-acid medicines, and some antidepressants. Never stop a prescribed medicine without speaking to your doctor first.
• Some cases seem to start after a bout of infection in the gut.
• Problems handling bile acids (digestive juices made by the liver) may play a part in some people.

Risk factors

• Being over the age of about 50
• Being female
• Taking certain long-term medicines, such as some anti-inflammatory painkillers, some stomach-acid reducers, and some antidepressants
• Having another immune-related condition, such as coeliac disease, thyroid disease, rheumatoid arthritis or type 1 diabetes
• A recent gut infection
• A family history of microscopic colitis or other immune conditions
• Smoking is linked with a lower risk of microscopic colitis, but smoking causes serious harm in many other ways — do not start smoking, and if you smoke, ask your doctor for help to quit

When to see a doctor

See a doctor urgently if:

• You have blood in your stool, or black tarry stools
• You have severe tummy pain, or a fever with tummy pain
• You feel dizzy, very thirsty, confused, or are passing very little urine — these can be signs of dehydration
• You cannot keep fluids down
• You are losing weight quickly or feel very unwell

Book a routine appointment if:

• You have had loose, watery stools for more than a week or two, especially if it keeps coming back
• Diarrhoea is affecting your work, sleep, travel or confidence
• You keep needing to rush to the toilet
• You feel tired or have lost a little weight without trying
• You have another immune condition and develop ongoing diarrhoea
• You are taking a long-term medicine and wonder whether it could be linked to your symptoms

Diagnosis

Doctors diagnose these conditions by putting together your symptoms, some stool and blood tests, and — most importantly — tissue samples (biopsies) taken from the lining of the bowel during a camera test. The camera test often shows a completely normal-looking bowel, which is exactly why the tissue samples matter. This is the key step that tells microscopic colitis apart from other causes of ongoing diarrhoea.

Tests that may be done

• A conversation about your symptoms, how long you have had them, your medicines and your general health
• Stool tests to check for infection and to rule out other causes of diarrhoea
• A stool test for a marker of gut inflammation called calprotectin
• Blood tests to check for anaemia, low vitamin levels, thyroid problems and, often, coeliac disease
• A colonoscopy or a flexible sigmoidoscopy — a camera test that looks inside the bowel
• Biopsies — tiny painless samples of the bowel lining taken during the camera test and checked under a microscope
• Sometimes a test to check how well your bowel handles bile acids

What to expect at your appointment

For a camera test you will usually be asked to take a bowel-clearing preparation the day before, and you may be offered light sedation to keep you comfortable. Taking the biopsies does not hurt. Results usually come back within a few weeks, because the tissue samples need time to be prepared and examined. If your results are normal, that is useful information too — it helps your doctor look in the right direction.

Treatment

Treatment aims to slow the diarrhoea, calm the inflammation and get you back to normal life. For some people, simply reviewing and adjusting medicines that may be triggering the condition is enough. For others, treatment is needed for a while, and many people find their symptoms settle well. Treatment is usually stepped up or down depending on how you respond.

Self-care at home

• Drink plenty of fluids. Oral rehydration salts, available from a pharmacy, replace water and salts lost through diarrhoea.
• Eat small, regular meals rather than large ones
• Notice whether caffeine, alcohol, very fatty foods, spicy foods or artificial sweeteners make things worse, and cut back on your triggers
• Keep a simple food and symptom diary for a few weeks to spot patterns
• Do not stop or change any prescribed medicine on your own — ask your doctor or pharmacist to review it with you
• Plan ahead: know where toilets are, carry spare underwear and wipes, and sit near exits when travelling
• Rest when you need to, and build gentle activity back in as you feel better
• Ask your pharmacist before starting any new over-the-counter medicine, including painkillers and indigestion remedies

Medical treatments

Doctors may use several approaches, depending on how severe your symptoms are. These include medicines that slow the bowel and firm up the stool, medicines that bind bile acids, and anti-inflammatory medicines. A short course of a steroid medicine that works mainly inside the bowel is often used to settle a flare, and courses can be repeated if symptoms come back. In people who do not respond, doctors may try other medicines that calm the immune system, and these are usually supervised by a specialist. Treatment is always tailored to you, and your doctor will explain the benefits and possible side effects of anything they suggest. Never start, stop or change a medicine without medical advice.

When is surgery considered?

Surgery is very rarely needed for collagenous or lymphocytic colitis. It is only considered in exceptional cases where symptoms are severe and do not respond to any other treatment. The vast majority of people are managed with medicines and lifestyle changes alone.

Living with this condition

Most people with these conditions live full, normal lives, but symptoms can be disruptive while they are active. Planning ahead makes a real difference — knowing where toilets are, carrying supplies, and telling people you trust about your condition can reduce stress. Flares often come and go, so it helps to know your early warning signs and to have a plan ready, such as contacting your doctor early rather than waiting.

Lifestyle tips

• Keep a simple diary of symptoms, foods and medicines so you can spot triggers
• Stay well hydrated, especially in hot weather or during a flare
• Cut back on alcohol and caffeine if they seem to set off symptoms
• Aim for regular, gentle exercise such as walking — it supports overall wellbeing and helps with stress
• Keep a 'just in case' bag with spare underwear, wipes and a change of clothes when you are out
• Ask your employer about flexible access to toilets or a workplace adjustment if you need one
• Have your medicines reviewed regularly, especially if you take painkillers or stomach-acid medicines long term
• Ask your doctor whether your vitamin levels should be checked if you have had symptoms for a while

Diet and exercise

There is no single 'microscopic colitis diet' that works for everyone. A balanced diet with small, regular meals suits many people. Some find that reducing caffeine, alcohol, very fatty or spicy foods, and fizzy drinks helps. If diarrhoea has been going on for a while, your doctor may check your vitamin and mineral levels. A dietitian can help if you are losing weight or struggling to eat well — ask your doctor for a referral. Gentle, regular movement such as walking, swimming or cycling is good for your gut, your mood and your sleep. Start gently and build up as your energy allows.

Mental health and emotional wellbeing

It is completely understandable to feel embarrassed, anxious or worn down by diarrhoea and urgency. Many people worry about accidents, avoid social plans, or feel stressed about travelling. These feelings are common and nothing to be ashamed of. Talking to your doctor about the emotional side is part of good care — it is not an afterthought. If low mood, anxiety or worry about your health is affecting your daily life, please reach out to a healthcare professional. If you ever feel unsafe or in crisis, contact your local emergency services or a local mental health crisis line straight away.

Prevention

There is no proven way to prevent collagenous or lymphocytic colitis from starting, because the exact cause is not known. What you can do is reduce the chance of flares and complications: have your medicines reviewed regularly, stay well hydrated, avoid smoking, eat a balanced diet, and see your doctor early if symptoms return. If a particular medicine seems to be linked to your symptoms, discuss alternatives with your doctor rather than stopping it yourself.

Vaccines

There is no vaccine for this condition. Keep up to date with routine vaccinations recommended in your area. If you take medicines that affect your immune system, ask your doctor which vaccinations are advised for you, because some are best given before treatment starts.

Screening programmes

There is no national screening programme for microscopic colitis. Because it is more common in people with other immune-related conditions, your doctor may offer tests such as a coeliac blood test or thyroid checks. If you have ongoing diarrhoea, ask your doctor whether further tests are appropriate rather than waiting.

Complications

If left untreated

• Dehydration, especially in older adults or during hot weather
• Weight loss and poor appetite
• Low levels of vitamins and minerals, such as iron, vitamin B12 or vitamin D
• Ongoing tiredness and low energy
• Reduced quality of life, with anxiety about going out, working or travelling
• Sleep disturbance from needing the toilet at night
• Rarely, bowel damage or perforation — this is very uncommon with these conditions

Long-term outlook

The outlook is generally good. Collagenous and lymphocytic colitis are treatable, they do not usually cause lasting damage to the bowel, and most people notice a big improvement with the right treatment. Some people have flares that come and go over months or years, and some find their symptoms settle for long stretches or go away altogether. Working closely with your doctor to find what suits you makes a real difference. If symptoms are affecting your life, tell your healthcare team — there is usually something more that can be tried.

Find support

External links open third-party websites. Ruqelo Health is not responsible for external content. Listing an organisation does not imply endorsement.