Eosinophilic Colitis

Overview

Eosinophilic colitis is a rare condition where a type of white blood cell called an eosinophil (say: ee-oh-SIN-oh-fil) builds up in the large bowel, also called the colon. Eosinophils are part of your immune system and normally help fight infection and allergic reactions. When too many of them collect in the bowel lining, they release chemicals that cause irritation and inflammation. This can lead to diarrhoea, tummy pain and other bowel symptoms. It is one of a group of conditions called eosinophilic gut disorders, and it is the least common type.

No, it is uncommon. Eosinophilic colitis is the rarest of the eosinophilic gut disorders, and experts do not know exactly how many people have it because mild cases may never be diagnosed. General bowel conditions such as irritable bowel syndrome and inflammatory bowel disease are far more common.

It can affect anyone at any age, but there are two peaks. The first is in babies and young children, where it is often linked to an allergy to a food protein and may settle as the child grows. The second is in adults, usually in their 30s to 50s. People with a personal or family history of allergies, asthma or eczema seem to be more likely to develop it.

Symptoms

Common symptoms

• Watery or loose poo, sometimes several times a day
• Tummy pain or cramping
• An urgent need to open your bowels
• Blood or mucus in your poo
• Bloating and wind
• Feeling sick or being sick
• Losing weight without trying
• Feeling very tired, which can be a sign of low iron levels

Symptoms in children

• Poor feeding or refusing feeds in babies
• Not putting on weight as expected, or slowing growth
• Being very unsettled or irritable, especially after feeds
• Vomiting or bringing up feeds
• Loose, bloody or mucousy poo
• A history of eczema, asthma or other allergies

Symptoms in older adults

• Looser stools that come on gradually and are put down to 'just a change with age'
• Weight loss and tiredness that may be mistaken for other conditions
• Anaemia (low iron in the blood) found on a routine blood test
• Symptoms that overlap with other bowel problems, which can delay the diagnosis

Causes

Main causes

• In many cases the exact cause is not known. It is thought to be an immune or allergic reaction to something in the gut, such as a food protein.
• In babies and young children, it is often linked to an allergy to cow's milk protein, and sometimes to soya or other foods.
• Sometimes it is a secondary problem: something else is raising the number of eosinophils in the body. Examples include parasite infections, reactions to certain medicines, inflammatory bowel disease, or other immune conditions.
• In some people no trigger is ever found, and the condition is described as 'primary' or 'idiopathic' (meaning of unknown cause).

Risk factors

• A personal or family history of allergies, asthma, eczema or hay fever
• A known food allergy, especially to cow's milk or soya in young children
• Living in or travelling to areas where parasite infections are common
• Taking a medicine that can trigger an allergic-type reaction, or starting a new medicine shortly before symptoms began
• Having another immune or bowel condition

When to see a doctor

See a doctor urgently if:

• You have blood in your poo
• You have severe tummy pain, or your tummy is swollen and hard
• You cannot keep any fluids down, or you feel very thirsty and dizzy
• You have a high temperature with bowel symptoms
• Your child is not feeding, is very sleepy, or has a dry nappy

Book a routine appointment if:

• Diarrhoea or loose poo that lasts more than two to four weeks
• Tummy pain that keeps coming back
• Weight loss you cannot explain
• Tiredness that does not improve with rest
• Bowels that are urgent or hard to control and are affecting your daily life
• A child who is not growing or gaining weight as expected

Diagnosis

There is no single test for eosinophilic colitis. Your doctor will ask about your symptoms, your diet, your medicines and any allergies, then arrange tests to look for other causes first. The key step is usually a colonoscopy (a camera test of the large bowel) with small tissue samples, called biopsies. Finding a higher-than-normal number of eosinophils in the bowel lining, alongside your symptoms and after other causes have been ruled out, is what points to the diagnosis. Because it is rare, you will usually be referred to a specialist in gut conditions (a gastroenterologist).

Tests that may be done

• Blood tests, including a full blood count to check for eosinophils and for anaemia
• Stool (poo) tests to look for infection, parasites and inflammation
• Colonoscopy or sigmoidoscopy: a thin, flexible tube with a camera is passed into the bowel, and small tissue samples are taken
• Biopsy: tiny pieces of the bowel lining are checked under a microscope for eosinophils
• Scans such as ultrasound or CT, if your doctor needs a wider view of the bowel
• Allergy tests or a food and symptom diary, if a food trigger is suspected
• A trial of a special diet with a dietitian, to see whether symptoms improve
• Review of your medicines, to check whether any could be causing the problem

What to expect at your appointment

The tests can take a few weeks to arrange and complete. The bowel preparation for a colonoscopy means drinking a special drink to clear your bowels, which is often the least pleasant part. The test itself is usually done with sedation or pain relief. You may be given a food diary to fill in, and you might be asked to try a change in diet for a few weeks before any results are final. Try to be patient with the process; ruling out other conditions is an important part of getting the right answer.

Treatment

Treatment aims to calm the inflammation, find and avoid any trigger, and keep you well nourished. Because the condition is rare, there is no single standard plan, so treatment is tailored to you. It often involves a combination of dietary changes, medicines to settle the inflammation, and regular follow-up.

Self-care at home

• Keep a simple diary of what you eat and your symptoms, which helps spot patterns
• Drink plenty of fluids, especially when you have diarrhoea
• Eat small, regular meals rather than large ones if your appetite is poor
• Do not start a strict elimination diet on your own, as this can lead to gaps in nutrition; ask for a referral to a dietitian
• Tell your doctor or pharmacist about any new medicine, supplement or herbal remedy you start
• Note down any questions before appointments so you do not forget them

Medical treatments

Your specialist will usually start by treating any underlying cause, for example clearing an infection if one is found, or stopping a medicine that may be responsible. If a food trigger is suspected, a dietitian may guide you through a planned trial of avoiding that food, then reintroducing it later to see whether it really matters. To calm the inflammation, doctors may prescribe medicines that reduce inflammation or settle down the immune response; these are usually used for a limited time and reviewed regularly. Some people need longer-term treatment or specialist liquid diets. Because everyone responds differently, your doctor will discuss the options, benefits and side effects with you before deciding together.

When is surgery considered?

Surgery is rarely needed. It may be considered only if there is a serious complication, such as a hole in the bowel, a blockage or a severe narrowing that does not respond to treatment. Most people never need an operation.

Living with this condition

Many people find that symptoms come and go. On good days, life can feel close to normal; on harder days, it helps to have a plan. Knowing where the toilets are, keeping spare clothes and wipes handy, and pacing yourself can reduce stress. Regular check-ins with your specialist and a dietitian help keep your diet balanced and your treatment up to date.

Lifestyle tips

• Eat regular, balanced meals and avoid skipping meals
• Stay active in a way you enjoy; gentle exercise such as walking can help with stress and general wellbeing
• Get enough sleep, as tiredness can make symptoms feel harder to cope with
• Limit alcohol and very spicy or fatty foods if you notice they make symptoms worse
• Plan ahead for travel, work and social events, and tell trusted people what helps you
• Ask your employer or school about adjustments if you need quick access to a toilet

Diet and exercise

There is no single 'eosinophilic colitis diet'. If a food trigger is found, avoiding it with a dietitian's help is the main dietary step, and the aim is always to keep your diet as varied and nourishing as possible. Some people find smaller, more frequent meals easier to manage. Exercise is generally safe and helpful; build up gently, drink enough, and rest when you need to. If you are losing weight or struggling to eat, ask for dietitian support rather than cutting foods out alone.

Mental health and emotional wellbeing

Living with a long-term bowel condition can be upsetting. It is completely normal to feel anxious about leaving the house, worried about tests, or frustrated when symptoms flare. These feelings matter, and they are worth talking about with your doctor, nurse or a counsellor. If you ever have thoughts of harming yourself or feel you cannot cope, contact your local crisis support line or your local emergency number straight away, or reach out to someone you trust and ask them to stay with you while you get help.

Prevention

There is no proven way to prevent eosinophilic colitis, because the exact cause is not fully understood. What you can do is manage known triggers: if you or your child has a confirmed food allergy, follow the advice you have been given, and tell your doctor about any reaction to a medicine. If you have had a reaction to a medicine before, mention it whenever a new one is prescribed.

Screening programmes

There is no screening programme for eosinophilic colitis. It is found through tests done because of symptoms, not through routine checks.

Complications

If left untreated

• Ongoing diarrhoea can lead to dehydration and low levels of salts in the body
• Losing blood in the poo over time can cause anaemia and persistent tiredness
• Poor appetite and poor absorption can lead to weight loss and, in children, slower growth
• Repeated inflammation can, in a small number of people, cause narrowing of the bowel
• Rarely, serious problems such as a hole in the bowel can develop, which is a medical emergency
• Symptoms can affect work, school, sleep and confidence if they are not managed

Long-term outlook

The outlook is generally encouraging. Many people improve once a trigger is identified or with a short course of treatment, and some children grow out of the condition entirely. Others have symptoms that come and go and need occasional review. Because it is rare, your team may take time to find the plan that suits you best, but most people are able to get back to a good quality of life with the right support.

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