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Crohn's diet

What are the symptoms of Crohn's disease?

Crohn's disease is a condition that is caused by inflammation of the gut. It is one of the inflammatory bowel diseases (IBD), alongside ulcerative colitis, the other main type of IBD. Crohn's is a lifelong condition, and can significantly affect the day-to-day lives of people with it. However, there are treatments that can help to control or reduce symptoms.

Crohn's disease mostly causes symptoms of gut problems. Common symptoms include:

  • Persistent diarrhoea,

  • Diarrhoea or poo (stools) with blood or mucus,

  • Tummy (abdominal) pain.

  • Weight loss

  • Tiredness (fatigue).

Crohn's disease can also cause symptoms outside the gut, like eye problems and some types of arthritis (joint inflammation).

If you think you may have Crohn's disease find out what to do here. This will tell you if you need to see a doctor and how it is treated.

In this series of articles centred around Crohn's disease you can read about symptoms of Crohn's disease, causes of Crohn's disease, and treatments for Crohn's disease- all written by one of our expert GPs.

The rest of this feature will take an in-depth look at the symptoms of Crohn's disease as, at Patient, we know our readers sometimes want to have a deep dive into certain topics.

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What are the symptoms of Crohn's disease?

Crohn's disease can affect any part of the digestive tract, and other organs as well. Its symptoms differ from person to person and depend on which part of the body is affected. People with Crohn's have times when symptoms are mild or absent, and times when they flare up.

Common symptoms include:


Diarrhoea - loose, or liquid, poo - often results from flare-ups and there might be blood, mucus, or pus in the poo.

Other poo problems

People with a Crohn's flare-up often have to go to the toilet many times a day (frequency), and may also find that they suddenly need to poo and get to a toilet quickly (urgency).

Crohn's affecting the rectum (the part of the bowel closest to the anus) can cause tenesmus - a feeling of needing to poo, but not actually being able to do so when trying.

Some people also get problems with constipation.

Tummy pain

Where you get tummy pain depends on which part of the gut is affected but, often, pain is felt in the lower right side of the stomach.


High temperatures (fevers) can develop in Crohn's flare-ups, especially in more severe ones.

Weight loss

Because eating can make Crohn's symptoms worse, you might eat less and have weight loss. Inflammation of the small intestine - which absorbs nutrients - can also cause problems with nutrition. It may be that some foods make symptoms worse than others.

Growth problems in children

In much the same ways as how it causes weight loss in adults, Crohn's disease can stop children from growing the way they should. Getting the disease under control can help with this.

Tiredness and exhaustion

Crohn's can cause people to feel very tired and exhausted. Exhaustion in Crohn's can be caused by:

  • Crohn's disease itself.

  • Problems such as anaemia.

  • Poor nutrition linked to weight loss.

  • Disrupted sleep if having to wake up at night with diarrhoea or tummy pain.

Mouth symptoms

People with Crohn's flare-ups often get mouth ulcers. Crohn's can also cause inflammation directly inside the mouth, causing lip and mouth swelling, although this is quite rare.

Symptoms around the anus

Around one in four people with Crohn's have inflammation that affects the anus and the area around it - perianal Crohn's disease. This can cause itching and pain of the anus and pain when pooing. Crohn's can cause anal fissures (cuts in the skin of the anus) and abscesses (deep infections) around the anus. It can also cause fistulas (abnormal connections) between the inside of the anus and the skin, which can leak. Some people develop faecal incontinence - an inability to control bowel movements/pooing.

Symptoms outside the digestive system

Crohn's disease can also cause problems in other organs outside the gastrointestinal (GI) tract, such as:

  • Arthritis - inflammation of the joints, causing pain, stiffness, and swelling. This can affect the joints of the arms and legs - like hands, elbows, shoulders and knees - or the spine.

  • Eye problems - redness and sometimes pain in the eyes linked with Crohn's include episcleritis and uveitis.

  • Skin problems - including psoriasis, tender red bumps under the skin (erythema nodosum) and a rare condition where an ulcer forms on the skin (pyoderma gangrenosum).

  • Osteoporosis - doesn't cause any symptoms by itself, but can increase the risk of fracturing bones. This can be one of the side-effects of medicines for Crohn's, especially steroids.

  • Liver and bile duct problems - are often found on a blood test but sometimes cause jaundice and itching.

Patient picks for Bowel problems

What does Crohn's disease feel like?

Crohn's causes different symptoms for different people. Some people might have relatively mild symptoms and go long times between flare-ups - others have more severe symptoms.

Some people with Crohn's describe the pain as feeling like a cramping pain, others, as a sharp, stabbing-type pain. For some, the pain is more like a bloating or a discomfort but others have severe pain that is impossible to ignore.

Diarrhoea and urgency are common. Suddenly having to use the toilet with little warning can cause major problems. For example, some people plan trips so that they are always close to a toilet that they can use if needed - toilet mapping.

People who are having a Crohn's flare often say they feel exhausted and wiped out.

Crohn's disease is a long-term, lifelong condition, and it can cause many symptoms that impact on people's lives. Living with Crohn's can be really difficult. Depression, anxiety, and other mental health problems are more common in people with Crohn's. However, treatments can help with the symptoms of Crohn's, and reduce how often flare-ups happen.

Continue reading below

How serious is Crohn's disease?

Crohn's disease can cause serious problems which vary depending on how well controlled the disease is. It can have a major effect on people's day-to-day lives. In rare cases, some complications of Crohn's disease can be life-threatening, if not treated promptly and effectively. There is no cure for Crohn's disease but treatment can reduce the risk of serious complications happening, and keep the condition under control.

When to see a doctor for Crohn's disease symptoms

Diarrhoea and tummy pain are symptoms that almost everyone will have at some point in their lives, and are more likely to be caused by other common illnesses, such as gastroenteritis. Things that suggest something else - such as Crohn's - might be a possibility, include:

  • Diarrhoea that has lasted more than two weeks.

  • Blood in the poo.

  • Repeated tummy pains or cramps, particularly if these last longer than a few weeks.

  • Losing weight without trying to, or noticing that a child is not growing as fast as expected.

People with Crohn's disease should be under the care of a specialist inflammatory bowel disease (IBD) team. They should be given a personalised action plan which details exactly what to do when a flare happens, including each treatment option. If you are developing a Crohn's flare, you should follow this plan, if you have one.

If you don't, or you are unsure what to do, you should contact your IBD team if you have their details - most places have a nurse hotline for this - or speak to a healthcare professional, such as your GP or 111 (if in the UK), urgently.

In an emergency - if you have severe tummy pain that does not get better with pain relief, have bloody diarrhoea, are repeatedly vomiting, unable to keep anything down, or feel your symptoms are severe, call 999 (if in the UK) or attend your nearest Emergency Department (A&E).

Continue reading below

How is Crohn's disease diagnosed?

If someone has signs and symptoms of Crohn's disease, there are several tests that doctors might arrange.

Blood tests

These might be done to look for:

Stool tests

These can include tests for:

  • Gut infections - like gastroenteritis.

  • Inflammation in the gut - a calprotectin test can be used rule out Crohn's and other types of IBD in people with symptoms of irritable bowel syndrome (IBS). In people who have a Crohn's diagnosis, faecal (poo) calprotectin is sometimes used to monitor the condition.

  • qFIT - tests for tiny amounts of blood in the poo that can't be seen with the naked eye to help doctors rule out bowel cancer as a negative/normal result makes cancer very unlikely. It can also be raised in inflammatory bowel disease, too, so some people referred urgently for endoscopy - a camera test - to rule out cancer after a positive qFIT test, are diagnosed instead with inflammatory bowel disease, particularly younger people.


Endoscopies are the main ways of diagnosing Crohn's disease. These let doctors look at the inside of the guts, which can sometimes show typical patterns of inflammation that suggest Crohn's disease, and, crucially, they allow doctors to take samples (biopsies) of the gut which are then examined under a microscope. Biopsies are important for showing exactly what type of inflammatory bowel disease is present.

The tests are chosen based on which part of the gut needs to be examined, and include:

  • An upper endoscopy (oesophagogastroduodenoscopy, OGD). This looks at the oesophagus (food pipe), stomach, and the first part of the small intestine, using a camera that goes into the mouth.

  • A lower endoscopy - usually a colonoscopy or a sigmoidoscopy which use a camera that goes into the bottom. A colonoscopy looks at the entire large intestine, and a sigmoidoscopy just looks at the last parts of the large intestine - the rectum and sigmoid colon.

  • Sometimes, a capsule endoscopy. This uses a swallowed 'pill camera' to look at the inside of the small intestine, which can't be reached by the other endoscopy techniques.

Imaging tests

These include:

  • CT scans and MRI scans - can be used in different ways, such as to look at the small bowel for narrowing, or to look at the anus and areas around it if someone has a fistula (connection) between the anus and somewhere else.

  • X-rays - done less often, because CT and MRI scans tend to give better information, but might be used to look for a blockage in the bowel. Another test uses barium - a chalky white fluid that shows up on X-rays - to look at the inside of the bowels. This is not done very much, as CTs and MRIs have mostly replaced it.

Crohn's disease complications

Crohn's disease can cause further complications. Some of these might need surgery to remove or fix.

  • Narrowing (strictures) of the inside of the gut - can cause a blockage in the gut.

  • Connections (fistulas) between the gut and other organs - can cause poo from inside the gut to get into other places. For example, people can develop connections between the gut and the vagina, or between the gut and the bladder.

  • Problems around the anus - like abscesses, fissures, and fistulas between the inside of the anus and the skin.

  • Bowel cancer - particularly in people with Crohn's affecting the colon (large bowel) who have a higher risk of developing bowel cancer. This risk is probably lower if the disease is kept under good control by treatment. People with Crohn's who are at risk are usually offered surveillance colonoscopies to look for early signs of cancer.

  • Malnutrition - Crohn's can stop people getting enough nutrition, causing them to lose weight, or in children, to stop growing as fast.

  • Blood clots, such as blood clots in the legs or in the lungs - people with Crohn's have a higher risk of these, especially during a flare.

  • Problems outside the gut.

Further reading

Article history

The information on this page is peer reviewed by qualified clinicians.

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