Crohn’s disease is a chronic inflammatory bowel disease that may affect the entire digestive tract. In a typical case, the last part of the small intestine, the ‘terminal ileum’, is affected. Abdominal pain and diarrhoea are among the most frequent symptoms of Crohn’s disease. Although Crohn’s disease cannot be cured, in most cases, the correct treatment can effectively control symptoms and improve quality of life.

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Crohn’s disease is a form of chronic inflammatory bowel disease (IBD) that usually ends up as a lifelong challenge for those affected. The symptoms of Crohn’s disease often occur in episodes and include abdominal pain, diarrhoea and occasionally fever. Although most cases of Crohn’s disease cannot be cured, with adequate treatment and careful monitoring there is usually only a slight reduction in life expectancy. Crohn’s disease may affect the entire digestive tract from the mouth to the anus, with typical cases involving the last section of the small intestine, the terminal ileum. The inflammation extends not only into the uppermost layer of the mucous membrane, but can also affect the entire intestinal wall. This means that the inflammation can also break through the intestinal wall and form abscesses or fistulas.

In contrast to Crohn’s disease, another chronic inflammatory bowel disease called ulcerative colitis affects only the large intestine and only the top layer of the intestinal wall, the intestinal mucosa. 

Risk factors

What exactly causes Crohn’s disease is still largely unknown. It is assumed that Crohn’s disease is caused by a complex interaction of several factors, including genetic predisposition, environmental factors, impairment of the intestinal barrier and smoking.

Genetic predisposition

Genetics play a part in Crohn’s disease, as the illness is more common in some families. Known gene mutations such as NOD2/CARD15 are only some of over 150 genetic risk factors that can increase the risk of Crohn’s disease.

Environmental factors

Certain environmental factors such as diet, hygiene, lifestyle and exposure to certain bacteria or viruses can have an effect on the risk of developing the disease.

Impairment of intestinal barrier

The penetration of bacteria into the intestinal wall can lead to severe immune reactions. If the function of the intestinal barrier is impaired, the body activates inflammatory cells to defend itself, even if the bacteria are not dangerous, which can ultimately cause intestinal inflammation.


Smoking is known to be a significant risk factor in Crohn’s disease and can have a lasting impact on the course of the disease. Studies have shown that smoking not only increases the risk of developing Crohn’s disease, but can also lead to a more severe course of the disease. It is suspected that the chemicals in tobacco smoke may increase inflammatory reactions in the intestine and impair the effectiveness of certain treatments. 

It is important to note that the presence of these risk factors may increase the risk of developing the disease, but does not necessarily lead to Crohn’s disease. The development of the disease is often the result of complex interaction between genetic, environmental and immunological factors.

Course of the disease

Crohn’s disease can manifest itself either chronically or acutely (intermittently). If the course of the disease is chronic, the symptoms last for at least six months. Most commonly, however, the disease occurs in episodes, alternating between phases with symptoms and symptom-free periods (remission). The severity, length and frequency of relapses vary greatly between those affected. This different courses that the disease may take make the treatment of Crohn’s disease an individual challenge in each case.


A variety of symptoms can be attributed to Crohn’s disease, the most common symptoms of Crohn’s disease are:

  • Abdominal pain
  • (Bloody) diarrhoea
  • Fever

Inflammation of the small intestine also often interferes with food intake and the diarrhoea leads to the loss of electrolytes, nutrients and fluids. This can lead to complications, including the following:

  • Anaemia
  • Tiredness
  • Shortness of breath
  • Loss of appetite
  • Weight loss
  • Other symptoms of deficiencies


The diagnosis of Crohn’s disease is usually performed by a specialist (gastroenterologist) and can be divided into the following steps: 

  1. Anamnesis (recording the medical history)
  2. Abdominal palpation for inflammation-related tenderness
  3. Analysis of the stool sample for inflammation values (calprotectin)
  4. Analysis of blood values for C-reactive protein (CRP) and nutrient deficiency
  5. Colonoscopy to examine the inside of the bowel and take a tissue sample if necessary
  6. Ultrasound (Ultrasound) of the lower abdomen to detect thickening of the intestinal walls
  7. Additional examinations such as a gastroscopy or magnetic resonance imaging (MRI)


The treatment of Crohn’s disease depends on the section of the digestive tract affected and the severity of the course of the disease. For mild cases, symptomatic treatment to relieve diarrhoea, cramps or pain may be sufficient. In severe cases of Crohn’s disease, cortisone or other medication is often used to suppress the autoimmune reaction.

Surgical interventions such as small intestine surgery or colon surgery are necessary in case of complications such as intestinal perforations, abscesses or the formation of fistulas. As a result of the increased risk of bowel cancer in Crohn’s disease, regular check-ups are essential.


As a result of the exact causes of Crohn’s disease are not yet fully understood, there are no specific preventive measures that would be able to prevent the disease completely. There are, however, some recommendations that could reduce the risk of developing the disease:

  • No smoking
  • A healthy diet
  • Stress management
  •  Avoidance of non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen or aspirin
  • Practice good hygiene


Nutrition plays a crucial role in Crohn’s disease and can vary depending on whether the patient is in remission or in the acute phase:

Remission phase (phase with no symptoms)

In the remission phase, an anti-inflammatory diet is crucial to strengthen the intestinal immune system. Wholesome nutrition with a sufficient amount of fibre and probiotics is recommended. In addition, a balanced diet should be maintained to provide the body with all of the necessary nutrients.

Acute phase

In the acute phase, high-fibre foods such as wholegrain products, raw vegetables and fruit should be avoided and easily digestible foods such as bananas, rice and cooked vegetables should be preferred. This can reduce the strain on the digestive tract and alleviate symptoms. 

An personalised dietary recommendation for Crohn’s disease can be provided in a nutritional consultation. In the case of Crohn’s disease, this is covered by basic insurance if prescribed by a doctor.

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