Crohn’s disease

Crohn’s disease (Crohn’s for short) is a chronic inflammation of the mucosal lining of the digestive tract. Symptom-free phases alternate with periods when abdominal pain and diarrhea may become so severe that they prevent people from living a normal life.

At a glance

  • Crohn’s disease is a chronic inflammation of the mucosa, i.e. the mucosal lining of the digestive tract. Crohn’s often affects segments of the bowel, i.e. the small and large intestine.
  • The disease usually occurs for the first time in young adults.
  • Symptom-free phases alternate with periods of cramping abdominal pain and diarrhea.
  • The precise causes of Crohn’s disease remain unknown. It is likely that genetic factors, environmental influences, and auto-immune disorders play a role.
  • The disease can severely impact a person’s quality of life.
  • There are many types of medication that alleviate the symptoms, though there is no cure.

Note: The information in this article cannot and should not replace a medical consultation and must not be used for self-diagnosis or treatment.

A woman sits bent forward on the toilet, holding a roll of toilet paper in her hand.

What is Crohn’s disease?

Crohn’s disease is a chronic inflammatory disease of the digestive system. In contrast to ulcerative colitis (another chronic inflammatory bowel disease or IBD), Crohn’s disease can affect any part of the digestive tract from the mouth to the anus. It can affect multiple, non-adjacent segments of the digestive tract.

However, the inflammation most commonly occurs in the final segment of the small intestine and in the adjoining segment of the large intestine. Crohn’s disease affects not only the uppermost layer of the mucosa but also deeper layers of the lining of the gut.

What symptoms are caused by Crohn’s disease?

Crohn’s disease can have various symptoms that occur either in isolation or in combination with one another. These include:

  • cramping abdominal pain
  • chronic diarrhea lasting at least 4 weeks – the stool may contain blood, mucus, or both
  • weight loss
  • fatigue
  • high temperature (fever)
Symptoms of Crohn’s disease include: cramping pains in the abdomen, chronic diarrhea, weight loss, fatigue, and high temperature (fever).

More rarely, the disease may cause stenoses, i.e. narrowing of the bowel, or fistulas, i.e. abnormal tunnels that develop between the anal canal and the skin around the anus.

Crohn’s disease may also cause symptoms in parts of the body outside of the digestive tract, e.g. inflammation of the eyes, joints, and skin.

What causes Crohn’s disease?

The symptoms of Crohn’s disease are caused by an inflammation of the intestinal mucosa that lines the digestive tract.

The body’s immune system attacks its own mucosa. It is not yet known what triggers this inappropriate immune system response.

However, research indicates that certain genetic changes increase the risk of developing Crohn’s disease. Auto-immune disorders, environmental influences, and imbalances in intestinal flora are also regarded as possible triggers.

What factors increase the risk of developing Crohn’s disease?

People who have close family members with an inflammatory bowel disease are also at an increased risk of developing Crohn’s disease.

Other inflammatory diseases or auto-immune disorders, as well as smoking and taking antibiotics are also considered risk factors.

How common is Crohn’s disease?

It is estimated that Crohn’s disease affects between 100 and 200 out of every 100,000 people in Germany. Every year, an average of around 7 out of every 100,000 people develop Crohn’s disease.

The disease usually begins in early adulthood between the ages of 20 and 30 approximately.

What is the outlook for Crohn’s disease?

Crohn’s disease is a chronic condition, which means that it cannot be cured.

However, very few people with the disease suffer from inflamed mucosal tissue on a continuous basis. Instead, they typically have recurring flare-ups that alternate with phases of being either symptom-free or having only mild symptoms. The inflammation clears up during these dormant phases.

However, if symptoms persist over a long period, they can lead to malnutrition, anemia, and, in some cases, life-threatening complications.

In addition, people with Crohn’s disease have an increased risk of developing bowel cancer (colorectal cancer). Doctors therefore recommend regular colonoscopies for early detection.

How is Crohn’s disease diagnosed?

Inflammation of the intestinal mucosa may have a range of causes. For example, it may be due to other chronic inflammatory diseases, such as ulcerative colitis, an acute infection, or a food intolerance.

Doctors can run various tests to exclude these possible causes and diagnose Crohn’s disease.

Doctors begin by taking a detailed medical history to pinpoint what type of symptoms are being experienced and when they began. They will also find out:

  • whether the patient has a known food intolerance
  • whether the patient is taking medication and, if so, which type
  • whether they smoke
  • whether they have family members with Crohn’s
  • whether they traveled abroad recently

Next, a blood test is performed to detect anemia, an elevated platelet count, as well as certain inflammatory markers that point to Crohn’s disease. A stool sample is also tested to exclude infections with intestinal bacteria.

If Crohn’s disease is suspected, doctors usually suggest an endoscopic examination of the colon (colonoscopy) and, in some cases, of the stomach (endoscopy/gastroscopy). A sample of mucosal tissue can be taken during this procedure.

Under certain circumstances, additional investigations, such as an ultrasound or magnetic resonance imaging (MRI) scan are required to determine the nature and severity of the disease.

How is Crohn’s disease treated?

The treatment of Crohn’s disease depends on its severity in each case, i.e. whether it causes mild or severe symptoms, as well as on the part of the body that is affected.

Crohn’s disease cannot be cured but it can be managed effectively with medication.

Crohn’s disease can often be managed effectively with medication. There have been significant advances in treatment options over recent years.

An operation may also be required in particularly severe cases or if complications arise. The surgery may involve opening segments of the bowel that have become narrowed or removing individual parts of the bowel.

How do people with Crohn’s disease cope with everyday life?

By adapting their diet, people with Crohn’s disease can improve their quality of life. Severe diarrhea often causes the body to lose vitamins, minerals, and trace elements. This, in turn, can lead to a deficiency in potassium, calcium, iron, or zinc. To prevent this, it is useful for patients to discuss a nutritional plan with their doctor.

It is advisable to avoid or quit smoking, as it can lead to a more severe progression of the disease.

Psychological support may help patients deal better with stressanxiety, or depression.

Important: As the immune system is often suppressed as part of treatment for Crohn’s disease, it is important to avoid infections as far as possible. People with Crohn’s disease should therefore check their vaccination status on a regular basis.

Where can I find more information about Crohn’s disease?

There are many services offering support for people with Crohn’s disease in Germany. These include self-help groups and advice centers.

You can find self-help groups through the database provided on the website of the National Contact and Information Point for Encouraging and Supporting Self-Help Groups (NAKOS).

In cooperation with the Institute for Quality and Efficiency in Health Care (Institut für Qualität und Wirtschaftlichkeit im Gesundheitswesen – IQWiG). As at:

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