Crohn's Disease

Overview

Crohn's disease is a long-term condition that causes inflammation (swelling and irritation) in the digestive system. It can affect any part from the mouth to the anus, but most often affects the small intestine or the beginning of the large intestine. The inflammation can cause pain, diarrhea, and make it hard for the body to absorb nutrients.

Crohn's disease is not rare, but it is also not very common. In the UK, it affects about 1 in every 650 people. It is becoming more common, especially in developed countries.

Crohn's disease can affect people of any age, but it is most often diagnosed in people between the ages of 15 and 35. It also runs in some families and is more common in people of Ashkenazi Jewish heritage.

Symptoms

Common symptoms

• Persistent diarrhea (sometimes with blood)
• Stomach pain and cramping, often in the lower right area
• Feeling very tired (fatigue)
• Unintended weight loss
• Loss of appetite
• Fever
• Mouth ulcers

Symptoms in children

• Delayed growth or puberty (because of poor nutrient absorption)
• Stomach pain that may not be clearly described
• Diarrhea that may be mistaken for a stomach bug
• Mood changes or irritability
• Anemia (low iron causing tiredness and pale skin)

Symptoms in older adults

• Joint pain or swelling
• Skin rashes (like tender red bumps on the legs)
• Fatigue that is more persistent
• Diarrhea that may be less severe than in younger people
• Weight loss that can be harder to notice

Causes

Main causes

• The exact cause is not known, but it is thought to be a combination of genetics, an abnormal immune response, and environmental triggers.
• In people with Crohn's, the immune system mistakenly attacks healthy bacteria in the digestive tract, causing chronic inflammation.
• Smoking is a strong trigger and makes Crohn's worse.

Risk factors

• Family history: having a close relative (parent, sibling, child) with Crohn's increases your risk.
• Age: most common in younger adults, but can occur at any age.
• Smoking: greatly increases risk and also makes the disease more severe.
• Ethnicity: people of Ashkenazi Jewish descent are at higher risk.
• Use of certain medications like nonsteroidal anti-inflammatory drugs (NSAIDs) (e.g., ibuprofen, naproxen) can trigger flare-ups.

When to see a doctor

See a doctor urgently if:

• Severe abdominal pain that makes you double over
• Bleeding from your bottom that is heavy or with clots
• Inability to eat or drink anything for more than 24 hours
• High fever (over 38.5°C / 101.3°F) that does not come down with paracetamol

Book a routine appointment if:

• Any symptom that lasts more than a few weeks, like diarrhea, stomach pain, or feeling very tired
• Unexplained weight loss
• Blood in your stool that is small amounts but happens more than once
• If you have a family history of Crohn's and you develop digestive symptoms

Diagnosis

Doctors diagnose Crohn's disease by reviewing your symptoms, doing a physical exam, and running tests to rule out other conditions and confirm inflammation. There is no single test; it is a process.

Tests that may be done

• Blood tests: to check for anemia, infection, or signs of inflammation (like C-reactive protein).
• Stool tests: to check for blood or infection.
• Colonoscopy: a camera on a thin tube passed into your bowel to look at the lining and take small tissue samples (biopsy).
• Magnetic resonance imaging (MRI) or CT scan: to get detailed images of your digestive tract.
• Capsule endoscopy: swallowing a tiny camera in a pill to take pictures of the small bowel.

What to expect at your appointment

Diagnosis can take time because symptoms can be similar to other conditions like irritable bowel syndrome (IBS). Your doctor will refer you to a gastroenterologist (a specialist in digestive diseases). You may need to have tests at a hospital or clinic, but most are done as an outpatient. The process may feel frustrating, but getting a clear diagnosis is the first step to treatment.

Treatment

Treatment for Crohn's disease aims to reduce inflammation, control symptoms, and prevent flare-ups. Because each person is different, your care team will tailor a plan for you. Treatment often includes a combination of medication, lifestyle changes, and sometimes surgery.

Self-care at home

• Quit smoking: this is the single most important thing you can do to improve your Crohn's.
• Keep a food diary to identify triggers like dairy, spicy foods, or high-fiber foods (but eat a balanced diet overall).
• Manage stress with relaxation techniques, exercise, or talking to a counsellor.
• Stay hydrated by drinking plenty of water, especially if you have diarrhea.

Medical treatments

Medications are used to reduce inflammation and control the immune system. Doctors may prescribe aminosalicylates to treat mild to moderate symptoms, corticosteroids for short-term flare-ups, immunomodulators to suppress the immune response, and biologic therapies that target specific proteins causing inflammation. Antibiotics may be used for infections. Always follow your doctor's advice and never change or stop medications without consulting them.

When is surgery considered?

Surgery may be needed if medications are not controlling the disease, or if there are complications like a blockage, fistula (an abnormal connection between the bowel and other organs), or abscess (a pocket of infection). Surgery usually involves removing the damaged part of the intestine and joining the healthy ends back together. Many people who need surgery feel much better afterwards, but the disease can come back in other areas.

Living with this condition

Living with Crohn's means managing symptoms day by day. You may have 'good days' and 'bad days'. It is important to take your medications as prescribed, keep regular appointments with your healthcare team, and learn to recognize early signs of a flare-up. Planning ahead — like knowing where the nearest toilet is — can help reduce anxiety.

Lifestyle tips

• Try to eat small, frequent meals instead of large ones.
• Keep a food diary to see what foods trigger your symptoms — but don't cut out too many foods without talking to a dietitian.
• Exercise regularly but listen to your body and rest when you need to.
• Get enough sleep: fatigue is common, and rest is part of management.
• Avoid smoking and limit alcohol, as both can make symptoms worse.

Diet and exercise

There is no one-size-fits-all diet for Crohn's, but many people find that eating low-fiber foods during flare-ups (like white bread, bananas, cooked vegetables) helps. A dietitian can help you avoid deficiencies. Gentle exercise like walking, swimming, or yoga can help with stress and overall health, but avoid heavy exercise during a flare.

Mental health and emotional wellbeing

Living with a chronic illness like Crohn's can be stressful and sometimes lead to anxiety or depression. The unpredictability of symptoms can affect social life, work, and relationships. It is normal to feel frustrated or worried. Talking to a mental health professional, joining a support group, or sharing with trusted friends can help. Remember to take care of your emotional health as well as your physical health.

Prevention

There is no known way to prevent Crohn's disease because the exact cause is not clear. However, if you have risk factors like a family history, you can reduce the chance of flare-ups by not smoking, managing stress, and eating a healthy diet. Once diagnosed, treatment and lifestyle changes can help keep the disease under control.

Vaccines

If you have Crohn's disease, it is especially important to stay up to date with vaccines, including the flu shot and pneumonia vaccine. Some vaccines that contain live viruses may not be safe if you are taking certain medications that suppress the immune system. Discuss vaccination with your doctor.

Screening programmes

People with Crohn's disease involving the large intestine have a higher risk of colorectal cancer. Your doctor may recommend colonoscopy screenings every 1 to 2 years after you have had the disease for 8 to 10 years. This helps detect any changes early.

Complications

If left untreated

• Intestinal blockage: when inflammation narrows the bowel passage.
• Fistulas: abnormal tunnels that form between the bowel and other organs or the skin.
• Abscesses: infected pockets of pus that can form near the bowel.
• Malnutrition: because the inflamed bowel cannot absorb nutrients properly.
• Anemia: from chronic blood loss or poor iron absorption.
• Increased risk of colon cancer if the disease affects the colon for many years.

Long-term outlook

While Crohn's disease is a lifelong condition, most people can achieve good control with treatment and live full, active lives. Flare-ups can be managed, and periods of remission can last years. Advances in treatment, especially biologic therapies, have greatly improved outcomes. Working closely with your healthcare team and making healthy lifestyle choices can make a big difference. There is hope for a good quality of life.

Find support

International organisations

• Crohn's & Colitis Foundation ↗
• European Crohn's and Colitis Organisation (ECCO) ↗

Local organisations

• Crohn's & Colitis UK ↗ · United Kingdom
• Crohn's and Colitis Canada ↗ · Canada
• Crohn's & Colitis Australia ↗ · Australia

Helplines

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