Digestive Disorders > IBD

What is Chronic Inflammatory Bowel Disease (IBD)?

Dr. med. Andre Sommer

Dr. med. Andre Sommer

The abbreviation “IBD” stands for inflammatory bowel disease and is an umbrella term mainly used for two conditions: Crohn’s disease and ulcerative colitis. Symptoms usually recur over time, so IBD is considered a long-term, or chronic disease. All forms of IBD affect the intestine and can be accompanied by similar symptoms, but in many cases other parts of the body are affected in addition to the intestine.

What diseases are considered inflammatory bowel diseases?

Crohn's disease and ulcerative colitis are the two main inflammatory bowel diseases. If inflammation in the large intestine cannot be clearly assigned to either of these diseases, the condition is referred to as “inflammatory bowel disease unclassified” (IBD-U), previously known as indeterminate colitis.

Chronic inflammation of the intestinal mucosa is present in both ulcerative colitis and Crohn's disease, but the exact location of the inflammation and the distribution pattern differ between the two diseases. Chronic inflammatory bowel diseases are not contagious.

What are the symptoms of IBD?

Chronic or relapsing diarrhea can be an indication of IBD. Diarrhea containing blood and mucus often occurs with ulcerative colitis, but this is rare with Crohn's disease. Diarrhea is often accompanied by severe abdominal pain in Crohn's disease. In some cases, constipation can alternate with diarrhea. Additional symptoms like cramps and abdominal tenderness may be present also.

How common is IBD?

About 1.3 percent of the American population, or about 3 million people, live with inflammatory bowel disease. Worldwide, 6 to 8 million people live with IBD.

The number of new cases of IBD in Western industrialized nations is steadily increasing. Although the exact origins of IBD are still unclear, IBD is seen as a so-called “disease of civilization,” which refers to diseases that are seen mostly in industrialized nations.

What should I do if I think I have IBD?

IBD does not usually begin with an acute episode, or a single episode with severe symptoms. As a rule, symptoms of IBD show themselves slowly.

Persistent, recurring diarrhea, like that seen in IBD,should be followed up by a healthcare provider. There are many causes of diarrhea. In addition to food intolerance, allergies, or acute gastrointestinal infections, irritable bowel syndrome (IBS) or IBD can also be present. Therefore, a comprehensive diagnostic examination with a gastroenterologist may be advisable if symptoms persist.

A healthcare provider will carry out various examinations to rule out or confirm IBD. The first steps can be taken by a primary care provider (PCP). If IBD is still suspected, people with IBD symptoms will be referred to a gastroenterologist, a physician specializing in conditions of the digestive system. In children, these examinations should be carried out in a specialized center with trained children's gastroenterologists, since the metabolism of a child differs from that of an adult.

A first visit for symptoms of IBD might consist of the following:

  1. Examination by a primary care provider:
  2. Detailed medical history
  3. Physical examination
  4. Blood and stool tests
  5. Examination by a gastroenterologist:
  6. Endoscopy—Examination of the inner lining of the intestine using a camera
  7. Biopsy—Tissue removal of small portions the inner intestinal lining or mucosa for tissue examination from various locations like the end of the small intestine or (ileum, the large intestine or colon, and the rectum or final portion of the large intestine)
  8. Ultrasound (sonography), X-ray, possibly magnetic resonance imaging (MRI) of the small intestine

Can children get IBD?

Crohn’s disease occurs most commonly between the ages of 15 and 35, while ulcerative colitis occurs most commonly between the ages of 20 and 40. While these are the average ages, it is still possible to develop a chronic inflammatory bowel disease even in infancy. The incidence of illness among children under the age of 10 is increasing.

When should a child be examined for IBD?

Children and adolescents should be examined if IBD is suspected. A clue here is if the child complains about the symptoms listed below for at least four weeks in a row or several times over the course of six months (two episodes or more).

Symptoms that might indicate IBD in children include:

  • Abdominal pain
  • Diarrhea
  • Weight loss
  • Malnutrition
  • Lack of appetite
  • Blood in stool (rectal bleeding)
  • Fatigue and pallor due to anemia (lack of red blood cells, e.g. when there is a lack of iron)
  • Fatigue (decrease in physical performance)
  • Fever
  • Delayed onset of puberty
  • Signs of bone demineralization
  • Fissures (tears) and fistulas (tube-like connections to other organs or to the body surface) in the area of the anus (opening where the digestive tract ends to the outside of the body)

The symptoms mentioned are particularly likely to occur with Crohn's disease. Ulcerative colitis is often only accompanied by bloody diarrhea.

It is important to note:


Only about a quarter of children with IBD show the classic symptoms of abdominal pain, diarrhea, and weight loss.


What causes IBD?

The causes of IBD are currently undetermined, but there are some factors that increase a person’s risk for IBD. First-degree relatives of people with IBD, like children or parents, have a four to eight-fold increased risk of also developing an IBD.

Some altered or mutated genes have been identified as associated with Crohn's disease. Experts believe that with these gene mutations, called the NOD2 gene, the immune system cannot effectively fight against invading bacteria. This allows the bacteria to stay in the intestine and penetrate the intestinal wall. When this occurs, the immune response is exaggerated and the intestinal inner lining becomes inflamed, causing abdominal pain and diarrhea.

During the course of IBD, pus accumulations or abscesses and fistulas can form due to the excessive inflammatory reaction. In the long term, IBD increases the risk of pathological vascular deposits called arteriosclerosis and events in the arteries. Chronic systemic inflammation is believed to be the cause.


Cigarette smoking increases the risk of cardiovascular and pulmonary (heart, vessels, and lung) diseases, and of several cancers. Smoking is also a risk factor for Crohn's disease and increases the severity of the disease. Nicotine may be considered a protective factor for people with ulcerative colitis.


Which parts of the body are affected by IBD?

IBD can also lead to inflammation and pain outside the intestine. These extraintestinal symptoms are various and common. If IBD results in painful joint inflammation, it is referred to as enteropathic arthritis or enteroarthritis (EA or EnA). A distinction is made between two types:

Enteroarthritis Type 1

  • Affects fewer than 5 joints – affects particularly knees, wrists and ankles
  • Occurs acutely as a flare-up
  • Is associated with IBD relapse and the presence of other extraintestinal symptoms
  • In 80 to 90 percent of people, the pain disappears within six months (also called spontaneous remission)

Enteroarthritis Type 2

  • Affects 5 joints or more – both large or small joints
  • May occur at any time during the course of IBD or before
  • Chronic course (months or even years) with frequent relapses
  • Multiple finger joints are more commonly affected by the painful inflammation

Symptoms affecting the joints may precede the IBD symptoms. In addition to the joints, extraintestinal symptoms of IBD are found primarily with the skin, eyes, and bile duct.

Does diet impact IBD?

The role of diet in the development and treatment of IBD is a controversial topic. It is clear that the risk of malnutrition is increased in IBD patients and that this worsens the prognosis. Because of this, malnutrition should always be addressed in people with IBD.

In addition to specific nutritional counseling, supplements of micronutrients can be used if necessary, like calcium, vitamin D, folic acid, vitamin B12, iron, and zinc.

Some studies suggest the use of probiotics can support ulcerative colitis during the remission phase (this is the phase with little or no disease activity). Probiotics are microorganisms with health-promoting bacterial cultures. The effectiveness of probiotics to maintain remission remains unclear and further trials comparing probiotics to standard medication used in the treatment of ulcerative colitis are necessary. There appears to be no additional positive effect of probiotics in Crohn's disease.

People with IBD often have intolerances to certain foods. Food intolerances and allergies may be tested and ruled out since they may be causing or worsening symptoms. Since the influence of eating habits on IBD has not yet been sufficiently clarified, there are no special dietary recommendations.

During an acute IBD episode, a diet that is particularly gentle on the intestines and low in fiber is recommended. In the symptom-free phase, substances such as psyllium and foods high in fiber should be included in the diet.

What foods are linked to IBD?

The tolerance of different foods is very individual with people impacted by IBD. You can find out which foods are causing you symptoms by keeping a food and symptom diary.

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Daily tracking of food and symptoms can help you determine patterns and relationships between certain foods and symptoms over time.

How is IBD treated?

There is unfortunately no cure for Crohn's disease or ulcerative colitis. One exception is the surgical removal of the colon in cases of severe ulcerative colitis. This extreme treatment is reserved for severe cases when there is no alternative treatment, and is not recommended for most people because it is an extensive operation that has significant side effects.

With both diseases, drug therapy aims to reduce inflammatory activity during flares or relapses, and depends on the severity of the inflammatory reaction. During the symptom-free phase (remission), an attempt is made to stabilize the disease with medication. The aim is to improve the quality of life and to maintain bowel function.

IBD is a lifelong disease, but its symptoms may come and go throughout the lifetime. IBD treatment usually involves medication and lifestyle therapy to keep the symptoms manageable and promote quality of life.

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Dr. med. Andre Sommer

Dr. med. Andre Sommer

I’m André, a medical doctor from Berlin. Together with a team of medical doctors, nutritionists and data scientists we empower people to understand digestive issues with our app Cara Care.

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