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Crohn's disease: symptoms, treatment & living with IBD
At a glance
FrequencyOne of the most common inflammatory bowel diseases (IBD); in Germany, estimates suggest several hundred thousand people are affected by an IBD
Age of onsetOften first between the ages of 15 and 35; a second peak can occur at an older age
CurableNot curable according to current knowledge — but usually very treatable; the goal is the longest possible remission
Pattern of involvementCan affect the entire digestive tract, most commonly the lower end of the small intestine (terminal ileum) and the large intestine
MedicationsCorticosteroids (flare), immunosuppressants (azathioprine, MTX), biologics (adalimumab, infliximab, ustekinumab, risankizumab and others), JAK inhibitor (upadacitinib)
Crohn's disease (in German "Morbus Crohn") is an inflammatory bowel disease (IBD). Unlike ulcerative colitis, which usually affects only the large intestine, Crohn's disease can affect the entire digestive tract — from the mouth to the anus. Most commonly, the lower end of the small intestine (terminal ileum) and the large intestine are affected.¹
A typical feature of Crohn's disease is that the inflammation can affect all the wall layers of the bowel (so-called transmural inflammation) and usually runs in flares: phases of active disease alternate with phases free of, or low in, symptoms (remission). Between the inflamed segments there can be healthy sections of bowel (so-called segmental involvement).¹
Crohn's disease vs. ulcerative colitis
Crohn's disease
Entire digestive tract possible
All wall layers (transmural)
Segmental involvement ("skip lesions")
Fistulas and strictures common
Surgery not curative
Ulcerative colitis
Large intestine only
Mucosa only
Continuous involvement
Visible blood in the stool typical
Colectomy potentially curative
In common
Chronic courses in flares
Misdirected immune reaction
Treatment partly overlaps
Extra-intestinal symptoms
Lifelong management
Not curable — but very treatable
With modern, individually adapted treatment, most of those affected can achieve a good quality of life over the long term. The treatment options have expanded considerably in recent years.¹,³
2. Symptoms
The symptoms depend on which section of bowel is affected, how strong the inflammation is and whether there are complications. Many symptoms are non-specific and at first are often misinterpreted as irritable bowel syndrome or a stress reaction.¹
Common bowel symptoms
Chronic diarrhoea — often over weeks, sometimes at night too; unlike ulcerative colitis, usually without visible blood
Abdominal pain — often in the lower right abdomen (with ileal involvement), can be cramping
Nausea, loss of appetite, weight loss
Bloating and a feeling of fullness
Fever — especially in acute flares
Complications in the bowel
Fistulas — abnormal connecting channels between the bowel and the skin, other organs or the anal area; affects a relevant share of those affected over the course of the disease
Strictures (narrowings) — through scar formation after repeated inflammation; can lead to bowel obstruction
Abscesses — collections of pus, often in the anal area
Symptoms outside the bowel (extra-intestinal)
Joint pain — the most common extra-intestinal manifestation
Tiredness and exhaustion (fatigue) — common even in remission
Iron deficiency and anaemia — through chronic inflammation and/or malabsorption
Increased risk of osteoporosis — especially with longer corticosteroid therapy
3. Causes and risk factors
The exact cause of Crohn's disease is not fully understood according to current knowledge. It is assumed to be an interplay of several factors.¹
Genetics: familial clustering. First-degree relatives of those affected have a markedly increased risk of disease. Several genes have been identified (including NOD2/CARD15) — but Crohn's disease is not a classic hereditary disease.
Immune system: reacts incorrectly to the body's own gut flora and components of the bowel wall. The result is a chronic inflammatory reaction that does not settle down on its own.
Gut microbiome: the composition of the gut flora is often altered in people with Crohn's disease (dysbiosis). Whether this is a cause or a consequence of the disease is still being researched.
Smoking: the most important modifiable risk factor. It increases the risk of Crohn's disease, worsens the course, increases the flare rate and the risk of surgery. Stopping smoking is one of the most effective measures.¹
Other factors: early antibiotic treatments in childhood, dietary factors (e.g. highly processed foods) and stress are discussed as possible influencing factors — the evidence here is not yet conclusive.
4. Diagnosis
A single examination is usually not enough for the diagnosis. Typically a combination of medical history, laboratory tests, imaging and endoscopy is used.¹
Ileocolonoscopy with biopsies: the most important examination. The large intestine and the lower end of the small intestine are assessed endoscopically and tissue samples are taken. Typical findings: segmental inflammation, a cobblestone appearance, longitudinal ulcerations, granulomas on histology.
Laboratory: CRP and the erythrocyte sedimentation rate (ESR) are usually elevated with active inflammation. Faecal calprotectin is a sensitive marker of the inflammatory activity in the bowel and is also suitable for monitoring the course. Blood count (anaemia?), iron, ferritin, vitamin B12, folic acid and vitamin D are usually measured as well.¹
MRI of the small intestine (MR enterography): the imaging of choice for the small intestine, which cannot be fully seen endoscopically. It shows wall thickening, strictures, fistulas and abscesses. It is done without radiation.
Abdominal ultrasound: can non-invasively show wall thickening, strictures and abscesses. It is often used as the first imaging and for monitoring the course.
In addition: a stool test for infections (especially Clostridioides difficile) to rule out an infectious cause. Capsule endoscopy if small-intestine involvement is suspected that was not seen on the MR enterography.
Treatment depends on disease activity, the pattern of involvement, the previous course and individual factors. The current S3 guideline of the DGVS (2024) recommends early, effective treatment with the goal of a steroid-free remission and, where possible, mucosal healing (endoscopic remission). The decision is usually made by the treating gastroenterology.¹,³
FlareCorticosteroid flare therapy
Budesonide
A locally acting corticosteroid preparation, often used as first choice for mild to moderately active Crohn's disease with ileal involvement. Fewer systemic side effects than conventional corticosteroids.
Systemic corticosteroids (e.g. prednisolone)
For a more severe flare or failure of budesonide. They work quickly but should usually be used for as short a time as possible — corticosteroids are not a long-term medication in IBD. More: Stopping corticosteroids.
MaintenanceImmunosuppressants
Azathioprine / 6-mercaptopurine
Often used for maintaining remission. The onset of effect usually takes a few months. Regular laboratory checks (blood count, liver values) are necessary.
Methotrexate (MTX)
An alternative, especially when azathioprine is not tolerated. More: Methotrexate.
BiologicsAnti-TNF, anti-IL, anti-integrin
Anti-TNF: infliximab, adalimumab
The longest-established biologics in Crohn's disease. They inhibit the inflammatory messenger TNF-alpha. They are usually used for moderate to severe disease or when immunosuppressants fail. Also effective for fistulas. Biosimilars are available and usually equivalent.¹,³
Anti-IL-12/23: ustekinumab
Inhibits interleukins 12 and 23. Often used when anti-TNF does not work well enough or is not tolerated.
Anti-IL-23: risankizumab
A newer biologic that specifically inhibits IL-23. It was added to the updated 2024 guideline and shows good efficacy in Crohn's disease in studies.³
Integrin inhibitor: vedolizumab
Acts selectively in the gut by inhibiting the migration of inflammatory cells into the bowel wall. Advantage: less systemic immunosuppression.
New 2023/24JAK inhibitor (oral)
Upadacitinib
An orally taken medication (a tablet instead of an injection/infusion). It was approved for Crohn's disease in 2023 and added to the guideline in 2024. It inhibits the Janus kinases (JAK), which are involved in transmitting the inflammatory signal.³
Corticosteroids are not a long-term medication
A so-called steroid-free remission is the treatment goal. If corticosteroids are needed repeatedly or over a longer period, a treatment escalation (e.g. to biologics) should usually be discussed.
6. Surgery
A relevant share of those affected need at least one operation over the course of the disease — often because of strictures, fistulas or abscesses that cannot be controlled adequately with medication. Surgery is usually carried out as sparingly as possible (bowel-sparing resection) in order to preserve as much healthy bowel tissue as possible.¹
After an operation, relapses (recurrences) often occur at the site of the anastomosis. Drug-based relapse prophylaxis after surgery is therefore usually recommended. Stopping smoking significantly lowers the risk of recurrence after surgery.
7. Nutrition
There is no single dietary form that can cure or reliably control Crohn's disease. Nevertheless, nutrition plays a relevant role.¹
In an acute flare: easily digestible food; with a severe flare, temporary enteral nutrition (drinkable nutrition) can be useful — in children, exclusive enteral nutrition is even an equivalent alternative to corticosteroids
In remission: a balanced, ideally minimally processed diet is generally recommended; a strict diet is usually not necessary
Identify individual intolerances: many of those affected do not tolerate certain foods — a food diary can help
Correcting deficiencies: iron, vitamin B12, folic acid, vitamin D, zinc and calcium should be checked regularly and supplemented if needed — especially with small-intestine involvement or after bowel resections
Psychological support (e.g. behavioural therapy, stress management) can considerably improve quality of life and is part of guideline-based care. The German Crohn's Disease / Ulcerative Colitis Association (DCCV e. V.) offers counselling and self-help groups.
9. Everyday life with Crohn's disease
Medications: regular and punctual intake is crucial — even in remission. Immunosuppressants and biologics protect against the next flare. Stopping them on your own increases the risk of a flare. More: Stopping medications.
Smoking: stopping smoking is the most important single measure those affected can take themselves. Smoking worsens the course, increases the flare rate and the risk of surgery.
Prevention/screening: regular colonoscopy checks are recommended with long-standing Crohn's disease involving the large intestine — the risk of bowel cancer is slightly increased over the long term. Have your bone density checked (osteoporosis risk with corticosteroids). Check your vaccination status — special vaccination recommendations apply under immunosuppression.
Work and travel: most of those affected can do a normal job with well-adjusted treatment. When travelling: take enough medications with you, observe the need to keep biologics cool.
Severe disability status and rehabilitation: with a severe course, a degree of disability (in Germany "Grad der Behinderung", GdB) can be applied for. Rehabilitation measures are a recognized benefit with IBD and can help in coping better with everyday life.
How brite helps you with Crohn's disease
Tapering corticosteroids, azathioprine daily, a biologic every few weeks — and in between, calprotectin checks, vitamin levels and the nutrition plan. IBD treatment is set up over years and needs a reliable routine. That is exactly what brite is built for.
Medication reminder — immunosuppressants daily, biologic appointments every few weeks, a corticosteroid tapering schedule in stepwise doses: brite reminds you on time. Especially with corticosteroid tapering, the right dose on the right day is crucial. Set up a reminder
Interaction check — azathioprine plus allopurinol (can raise the level dangerously)? MTX plus ibuprofen or trimethoprim? A biologic plus a live vaccine? brite shows the critical combinations in IBD treatment. Check now
Health history — document flare activity, calprotectin, CRP, stool frequency, weight and accompanying symptoms (fatigue, joints) over time. At your next gastroenterology appointment, show what really happened. Track your history
Digital medication plan — all your IBD medications clearly laid out for gastroenterology, your family doctor and the emergency department. In an emergency, those treating you immediately see which immunosuppressants and biologics you are taking — important for example with acute infections. Go to medication plan
Both are inflammatory bowel diseases (IBD). Crohn's disease can affect the entire digestive tract and involves all the wall layers; ulcerative colitis is usually limited to the large intestine and the mucosa. The treatment partly overlaps but differs in important details — for example, a surgical cure is only possible with ulcerative colitis (colectomy).¹
Not according to current knowledge. The goal of treatment is the longest possible remission — that is, a phase without symptoms or with minimal symptoms and, ideally, a healing of the bowel lining. Many of those affected achieve a good quality of life with modern treatment.¹,³
No — in Crohn's disease, corticosteroids are usually a flare medication and not a long-term medication. If corticosteroids are needed repeatedly or for longer than a few months, a treatment escalation (e.g. to biologics or immunosuppressants) should usually be discussed. A steroid-free remission is the treatment goal.¹
Biologics are biotechnologically produced medications that specifically block certain inflammatory messengers. In Crohn's disease, those approved include infliximab, adalimumab (anti-TNF), ustekinumab (anti-IL-12/23), risankizumab (anti-IL-23) and vedolizumab (integrin inhibitor). They are usually given as an infusion or injection.¹,³
A JAK inhibitor that is taken as a tablet — not a biologic in the narrower sense but a so-called small molecule. It was approved for Crohn's disease in 2023 and added to the German guideline in 2024. It inhibits the Janus kinases, which are involved in the inflammatory reaction.³
There is no single Crohn's disease diet. In a flare, easily digestible food is usually recommended; in remission, a balanced, ideally minimally processed diet. Individual intolerances should be identified (food diary). Deficiencies (iron, B12, vitamin D) should be checked regularly and supplemented if needed.¹
Stress does not cause Crohn's disease — but it can promote flares and intensify the perception of symptoms. Stress management (e.g. behavioural therapy, relaxation techniques, regular exercise) is recommended as a supplement to drug treatment.
Yes — with well-adjusted treatment, most of those affected can do a normal job. With a severe course or frequent flares, a degree of disability (in Germany "Grad der Behinderung", GdB) can be applied for, which offers employment-law protections and compensation for disadvantages.
Medical disclaimer: This article is for general information and does not replace medical advice, diagnosis or treatment. IBD medications should usually not be stopped on your own or have their dose changed. If there are signs of a severe flare (severe abdominal pain, high fever, bloody diarrhoea, signs of a bowel obstruction), seek medical help immediately. The choice of medication and dosing is always determined individually by the treating gastroenterology. Last updated: April 2026.
