Crohn’s disease

Crohn's disease is a long-term condition that causes inflammation of the lining of the digestive system.

The inflammation can affect any part of the digestive system, from the mouth all the way to the back passage. Most often, though, it shows up in the last section of the small intestine (the ileum) or in the large intestine (the colon).

Crohn's disease can affect people of any age, but it's usually diagnosed between the ages of 15 and 40.

Crohn's disease doesn't look the same in everyone. The symptoms depend on which part of the digestive system is inflamed.

Common symptoms include:

• recurring diarrhoea
• abdominal pain and cramping, which is usually worse after eating
• extreme tiredness (fatigue)
• unintended weight loss
• blood and mucus in your poo

Some people have long periods with no symptoms at all, or only very mild ones. This is known as remission. It may then be followed by a spell when the symptoms become particularly troublesome. These spells are known as flare-ups or relapses.

Less common symptoms include:

• a high temperature (fever) of 38°C (100°F) or above
• feeling sick (nausea)
• being sick (vomiting)
• joint pain and swelling (arthritis)
• inflammation and irritation of the eyes (uveitis)
• areas of painful, red and swollen skin, most often on the legs
• mouth ulcers
• anal pain and discharge due to perianal Crohn's

Children with Crohn's disease may grow at a slower rate than expected.

• diarrhoea for more than 7 days
• persistent abdominal pain
• unexplained weight loss
• blood in your poo
• concern about your child's development

No one knows the exact cause of Crohn's disease. It may come from a combination of factors, including:

• genetics, meaning the genes you inherit from your parents
• a problem with the immune system (the body's defence against infection and illness), where it attacks healthy bacteria in the gut and causes inflammation
• environmental factors, like air pollution, medicine or previous infections
• smoking, because smokers are twice as likely to develop Crohn's disease, and they usually have more severe symptoms than non-smokers

Your doctor will usually start by asking about a few things:

• the pattern of your symptoms
• your diet
• any recent travel (for example, you may have picked up travellers' diarrhoea)
• any medicine you're taking, including medicines you buy over the counter
• any bowel conditions in your family

Your doctor may also carry out some tests to check your general health. For example, they may:

• check your pulse
• check your blood pressure
• measure your height and weight
• measure your temperature
• examine your abdomen (tummy)

Your doctor may also:

• arrange blood tests to check for inflammation, infection and anaemia
• ask for a stool (poo) sample, which is used for a qFIT test to check for blood and mucus, infection or inflammation via a faecal calprotectin test

Your doctor may refer you to a gastroenterologist, who is a specialist in conditions of the digestive system. They might recommend more tests, such as:

• gastroscopy, where a thin, flexible tube with a camera is put into your mouth to look at your food pipe and stomach
• colonoscopy, where a thin, flexible tube with a camera is put into your bottom to look at the whole of your large bowel
• sigmoidoscopy, where a thin, flexible tube with a camera is put into your bottom to look at the end of your large bowel
• a colon capsule endoscopy (pill camera)
• X-ray or barium enema
• MRI scan or CT scan

You will be told what tests you need and what you need to do to prepare for them.

There's no cure for Crohn's disease at the moment, but treatment can ease the symptoms and keep the inflammation under control. You will usually be looked after by several different health professionals, not just one.

Once your symptoms are under control, you are likely to be offered treatment to help keep them that way. If your Crohn's stays under control for a long time, you may choose to stop treatment. You may need to start again if your symptoms come back.

For Crohn's disease, the first treatment is usually a steroid medicine (a corticosteroid), such as prednisolone or budesonide. These bring down inflammation quickly, and they often ease your symptoms well. But steroids can cause significant side effects, so they aren't suitable for long-term use. Once your symptoms start to improve, your doctor will slowly reduce your dose.

Your doctor may give you medicines that suppress the immune system (immunosuppressants) alongside steroids if your Crohn's disease flares up twice or more during 12 months, or if the symptoms come back when your steroid dose is reduced.

The ones most often used are azathioprine, mercaptopurine and methotrexate.

If steroids and immunosuppressants don't help, or aren't right for you, your doctor may suggest biological therapies for Crohn's disease.

These medicines block particular chemicals involved in the immune response, and that helps reduce inflammation. They're made using living cells in a lab. You can have them as a drip or as an injection. Treatment usually lasts at least 12 months. Your inflammatory bowel disease (IBD) team can talk these through with you.

The common types are adalimumab, infliximab, ustekinumab or vedolizumab.

These medicines may cause side effects, and some of them show up as symptoms such as:

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

If you notice any of these symptoms, seek medical help immediately. Reactions can happen straight after treatment or months later, even after treatment has stopped.

Surgery for Crohn's disease may be an option if:

• you choose to have surgery instead of taking medicines that may cause side effects
• medicines don't control your symptoms
• your quality of life is severely affected by your condition
• you have serious complications of Crohn's disease

The operation might widen narrow parts of your bowel, or remove parts of it (this is called resection). In a resection, the doctor takes out the inflamed area of the intestine.

After a resection, the healthy sections of bowel might be joined back together. Or the end of your small bowel might be joined to the skin of your tummy (an ileostomy, also called a stoma). If that happens, poo comes out through the opening on your tummy and is collected in special bags that you wear. An ileostomy might be temporary, to give your bowel time to heal, or it might be permanent.

Your IBD team will tell you which surgery they recommend and what to expect.

No one has found evidence that a particular diet causes Crohn's disease flare-ups or triggers them. Still, alongside your medicines, some changes to what you eat may help control symptoms for some people.

• eat 5 to 6 small meals rather than 3 main meals
• try to eat a healthy, varied diet with many different kinds of fruit, vegetables, nuts, seeds, proteins and wholegrains
• drink plenty of water

Don't make major changes to your diet without talking to your IBD team, and make sure you are still getting all the nutrients you need. You can speak to your IBD team about:

• keeping a food diary to find out if any particular foods affect your symptoms
• removing trigger foods from your diet
• taking a food supplement if you are struggling to get enough nutrients from your diet
• being referred to a dietitian

If you smoke, you are advised to make every effort to stop, especially if you need to have surgery.

Smoking can make Crohn's disease worse, so it matters a great deal that you make every effort to stop.

Crohn's disease doesn't usually affect a woman's chance of becoming pregnant. Surgery for Crohn's disease, though, might affect your fertility.

Most women with Crohn's disease have a normal pregnancy and a healthy baby. Still, if you're pregnant or planning a pregnancy, talk to your IBD team about it, because they may need to change your medicine.

If you're having a flare-up of Crohn's disease, you may also be advised to avoid getting pregnant until it's under control.

Over many years, the inflammation in Crohn's disease can damage parts of the digestive system. That damage can lead to complications such as:

• narrowing of the bowel (stricture)
• a channel developing between your bowel and your skin, another section of bowel or a body organ (fistula)

These problems usually need surgical treatment.