Digestive Disorders > IBD > Crohn's Disease

Crohn's disease: The need-to-know symptoms

Dr. med. Andre Sommer

Dr. med. Andre Sommer

Crohn's disease is a chronic inflammatory bowel disease often preceded by an odyssey of doctor visits and examinations before it can be diagnosed and treated. The reason for this is that the symptoms are often not very meaningful and can easily be confused with other diseases of the gastrointestinal tract. The symptoms also vary greatly from patient to patient and can quickly be misinterpreted. Crohn's disease is mostly associated with diarrhea, but there are many other symptoms as well. As with all chronic inflammatory diseases of the intestinal tract (IBD), timely diagnosis is crucial to prevent long-term damage.

What are the most common symptoms in Crohn's disease?

The form and intensity of the symptoms that appear depends on how severely the digestive tract is affected. In the early stages of the disease, those affected often initially just feel uncomfortable: They have bloating and diarrhea. The more pronounced the disease, the stronger the symptoms.

The most common symptoms of Crohn's disease at a glance:
●   Diarrhea
●   Severe abdominal pain and cramps
●   Blood in the stool
●   Fatigue
●   Weight loss
Sometimes, all symptoms occur at the same time.

What symptoms are experienced in the gastrointestinal tract?

The first signs of Crohn's disease (known as cardinal symptoms) are the same in most patients. These include:

  • Mashy to liquid diarrhea
  • Stomach pains, including cramps
  • Bloating

**Important! **Due to this constellation of symptoms, further problems such as being underweight and malnutrition often arise.

These symptoms are not very specific and leave a lot of room for interpretation. Everyday, people with similar complaints see a doctor. In many cases, the doctor initially assumes that the symptoms are rather harmless and suspects an infection or virus. However, Crohn's disease patients suffer longer from their symptoms than healthy people.

Important! Long and severe inflammatory reactions also increase the risk of degeneration over time. The result is a malignant cancer, which mainly affects the colon.


Recurring diarrhea is one of the most important symptoms. It is usually watery to slimy and is accompanied by cramping abdominal pain. In contrast to ulcerative colitis, Crohn’s-related diarrhea is less frequently bloody.

Crohn's disease patients report the persistent, extremely painful feeling of constant urge to use the restroom. Doctors describe this phenomenon as so-called tenesmen (from the Greek teinesmós = "constipation").

Stenoses and bowel obstruction

Depending on the duration and extent, complications that require surgery can arise in the course of the disease. These include, for example, so-called stenoses, because these constrictions or restrictions can cause intestinal obstructions and thus prevent the intestinal contents from being transported.

Fistulas and fissures

If one has Crohn's disease for years, the inflammation has a damaging effect on the mucous membranes and stomach walls. Fistulas or fissures can result. Fissures are skin cracks, which arise primarily in the area of the anus. By contrast, fistulas are the ducts between the intestinal sections or between the intestine and skin.

Severe Crohn’s disease complications

In the long term, chronic inflammation affects the intestinal mucosa. If Crohn's disease has existed for years, it can severely damage the mucous membranes. The consequences include:

  • Inflammatory cracks in the skin (fissures), especially in the area of the anus
  • Cavities filled with pus (abscesses)
  • Connections between two intestinal loops, the intestine and the abdominal wall or to other organs such as the bladder (fistulae)
  • Holes in the intestinal wall (perforations) through which the contents of the intestine enter the abdominal cavity and can cause a serious infection (peritonitis). Intestinal perforations require immediate medical attention.
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What symptoms appear outside the digestive tract?

Crohn's symptoms are not only manifested in gastrointestinal complaints. Evidence for the disease can also be found outside the digestive tract. Some examples of this are:

  • Joint pain and inflammation (arthritis)
  • Inflammation and reddening of the eyes
  • Liver and gallbladder problems
  • Fever
  • Skin cracks and inflammation (often on the legs and in the mouth)
  • Fatigue
Organ Symptom
Skin Open spots in the oral mucosa (aphthae) in about 10 percent of those affected, red painful nodules on the skin (erythema nodosum), large skin ulcers (pyoderma gangraenosum)
Eyes Redness, inflammation
Joints Inflammation of the joints (arthritis) in over 10 percent of those affected,
Liver and gallbladder Inflammation of the liver (primarily sclerosing cholangitis), fatty liver

Fig. 1. Crohn's symptoms outside the digestive tract.

In principle, any region of the body can become inflamed. The other symptoms of Crohn's disease are therefore diffuse and sometimes insufficiently understood.

Symptoms in the mouth area

Anatomically, the mouth area still belongs to the digestive tract, but these symptoms of Crohn's disease are understood as being outside the gastrointestinal tract. In addition to the oral mucosa, the gums and lips can also be affected. Here patients experience painful symptoms like

  • Redness
  • Swelling
  • Small blisters
  • Inflammatory areas with a whitish coating (aphthae)

Skin symptoms

The skin can also become inflamed with Crohn's disease. The legs are mostly affected, particularly the lower legs. Depending on the type of inflammation, doctors make a distinction:

  • Inflammation of the subcutaneous fatty tissue with reddish papules (erythema nodosum)
  • Inflammatory and extremely painful ulcers with blisters, pustules, black discoloration and dead skin areas (necrosis) - So-called pyoderma gangrenosum occurs only rarely in the context of Crohn's disease and is somewhat more common in ulcerative colitis

Joint symptoms

The joints (enteropathic arthritis) are often affected by inflammation. Many patients even report pain in the joints (arthralgia) and spine before problems in the gastrointestinal tract.

The complex structure of our eyes does not protect them from being affected by inflammation as part of Crohn's disease. Depending on which areas of the eye are affected, one speaks of different types of inflammation.

  • Inflammation of the middle eye skin (uveitis) includes the choroid (choroid), the radiation body (corpus ciliare) and the iris (iris)
  • Inflammation of the iris alone (iritis)
  • Inflammation of the external dermis (scleritis)

Symptoms of the bile and liver

Inflammation of the liver and bile ducts is a rare variant of Crohn's disease and is more common in ulcerative colitis. If the biliary tract becomes chronic and shows scarred hardening and narrowing over time, this is called primary sclerosing cholangitis.

What influence does the disease have on the psyche?

Crohn's disease can have a negative impact on general well-being and the psyche. Many of those affected feel severely restricted in their lives due to the illness—in their partnerships, at work, and in their free time.

The frequent urge to use the restroom during an active flare-up means that those affected always have to be near the restroom. For most people, travel, sport, or other leisure activities are not possible during a flare-up. Many patients therefore reduce their social interactions and withdraw.

How does Crohn's disease present in children?

Children and infants can also be affected by Crohn's disease. Unlike adults, the disease in adolescents is also associated with considerable developmental delays. The causes of this are frequently occurring diarrhea and loss of appetite. Inflammation of the digestive organs also leads to poor nutrient absorption. This leads to feelings of exhaustion and delays in development. Affected children therefore often grow more slowly. Puberty also begins later.

As with adults, Crohn's disease in children doesn't just affect the digestive system. Other organs are also affected and changes to the eyes, skin or joints are not uncommon.

How common are Crohn's symptoms?

Crohn’s disease occurs intermittently. This means that those affected do not continuously suffer from the corresponding symptoms. Between the flare-ups, most patients live completely symptom-free without loss of quality of life. In principle, when, how often and the degree to which flare-ups occur varies from person to person. Some sufferers experience Crohn's symptoms for only a few days. Others over several weeks.

How is Crohn's disease diagnosed?

The course of Crohn's disease also varies from patient to patient. Since the disease begins slowly, the symptoms cannot always be correctly interpreted and classified immediately.

There is no specific value for the detection of the disease, but blood tests and stool tests provide important information. In order to diagnose Crohn's disease, the person concerned must describe the symptoms to the doctor in detail and indicate possible intestinal diseases in the family. Examinations of the abdomen and anus help identify hardening and other changes that indicate Crohn's disease.

What are signs of malnutrition with Crohn's disease?

Our intestine is not only responsible for thickening food and processing it into stool, it also draws out the liquid and the important nutrients that we ingest with food. If the intestinal wall is constantly inflamed, the absorption of nutrients will no longer work properly. The body then reacts to this lack of nutrients in different ways. Some especially characteristic symptoms include:

  • Weight loss
  • Loss of appetite
  • Fatigue
  • Stunted growth in children
  • Anemia due to chronic inflammation, the loss of iron due to bleeding in the intestine, and the lack of vitamin B12 (cobalamin), which is important for the regular formation of red blood cells (erythrocytes)
  • Faulty resumption of bile acids and associated diarrhea, greasy bowel movements, lack of fat-soluble vitamins, gallstones, and urinary stones
  • Skin detachments on the hands, feet, and in the genital area caused by zinc deficiency, which resemble the so-called acrodermatitis enteropathica

The symptoms of Crohn's disease are as varied as their treatment is complex. Therapy aims to improve the quality of life and also to prevent the disease from progressing. For this purpose, the doctor works out an individual therapy plan with the patient, which contains aspects of a change in diet, medicinal, and possibly also operative therapy.

How can Crohn's symptoms be relieved?

Crohn’s disease is not curable. However, a medical treatment tailored to the patient and an adaptation of the patient's lifestyle can contribute both to extending intervals between flare-ups and to alleviating the symptoms that occur.

**Tips for Crohn’s disease patients**
  • Regular visits to the doctor and monitoring of blood values help with the right choice of therapy and with the early detection of any complications.
  • A nutrient-rich diet with lots of vitamins and trace elements reduces deficiency symptoms.
  • It is very helpful to quit smoking: The flare-ups occur less often and the risk of a severe course of the disease decreases.
  • Relaxation exercises, self-help groups, and conversation therapies help patients to deal with the psychological stress

If previously unknown symptoms appear or a new attack occurs, those affected should contact a doctor as soon as possible to adjust the therapy and medication accordingly.

Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften. AWMF – Leitlinien. Langfassung der Leitlinie. Diagnostik und Therapie des M. Crohn. Register Nr. 021-004. Downloaded online on 22/05/2018 from http://www.awmf.org/uploads/txszleitlinien/021-004lS3MorbusCrohnDiagnostikTherapie_2014-09.pdf.

Conrad S., Muche-Borowski. C., Raspe H. (2009): Evidenzbasierte und interdisziplinär konsentierte Versorgungspfade für Patientinnen und Patienten mit Morbus Crohn oder Colitis ulcerosa, online downloaded from https://www.thieme-connect.com/products/ejournals/abstract/10.1055/s-0028-1109323#AZfG-0107-1.

Seminar F. (2015): Stenose bei Morbus Crohn: Dilatation oder Operation?, CME, Volume 12, pp 34. Downloaded online on 22/05/2018 from https://link.springer.com/article/10.1007/s11298-015-1529-9.

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.

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