Health Hub

Crohn's Disease

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Crohn's Disease

In this Health Hub article, we explore the signs & symptoms, causes, diagnosis, and treatments of Crohn's disease.


Crohn's disease is one of the most common inflammatory bowel diseases (IBD). It is a long-term condition which can affect any part of the gastrointestinal tract from the mouth to the anus. Ulcerative Colitis (UC) is another IBD which is restricted to the large intestine.  Crohn’s Disease results from an inflammatory response leading to swollen, inflamed and ulcerated intestines. It not only causes inflammation of the lining of the intestine but also inflammation deeper into the tissue which can lead to perforation of the bowl in severe cases. Crohn's Disease is described as having a “cobble stone”  or “skip lesion” appearance, while UC appears as continuous inflammation.

Facts & Figures

  • In Ireland in 2011 there were 5.9 new cases of Crohn's disease recorded per 100,000 people, making Crohn’s disease a rare condition.
  • Males and females are affected equally.
  • First signs develop in between 16 and 30 years of age, although the condition can affect people of all ages.

Signs & Symptoms of Crohn's

  • recurring diarrhea
  • abdominal pain and cramping which is usually worse after eating
  • blood and mucus in stools
  • fatigue
  • weight loss
  • growth retardation in children

What Causes Crohn's ?

The cause of Crohn’s disease is unknown, however, there are a number of factors which research shows could contribute to the condition. Factors include:

  • Genetics – if you have a first degree relative to the condition you are 5-10% more likely to develop the condition.
  • The immune system: the digestive system is made up of both good and bad bacteria. It appears that in Crohn's disease the immune system is disrupted resulting in a specific antibody known as tumour necrosis factor (TNF) being released and kill both the good and bad bacteria. It is this TNF antibody that causes the inflammation seen in Crohn’s disease.
  • Previous infection: a previous bacterial or viral infection may trigger an abnormal response from the immune system.
  • Environmental factors: the fact that Crohn's disease is most common in westernised countries, such as Ireland, and least common in poorer parts of the world, such as Africa, may be due to environmental factors e.g. increased hygiene and the use of refrigerators.


There are a combination of tests and procedures used to help diagnosed Crohn’s disease and to rule out other possible conditions. There is no one test to diagnose Crohn's disease.

Blood Tests:

  • Tests for anemia or infection - Your doctor may suggest blood tests to check for anemia (low red blood cell count) or signs of infection.
  • Fecal occult blood test – this will require you to supply a stool sample to test for hidden blood in your stool.


  • Colonoscopy - This is a when a small, lighted tube with an attached camera is used to view the entire colon. It allows the doctor to see any signs of inflammation, ulceration and to take tissues samples if necessary.
  • Computerized Tomography (CT) and Magnetic resonance imaging (MRI) – these are scans which collect in-depth images of the entire bowel as well as the tissues outside the bowel.
  • Capsule endoscopy – this involves swallowing a capsule that has a camera in it. As the capsule passes through the intestine it takes pictures of the intestine. The images can be downloaded to a computer and examined for signs of Crohn’s disease.
  • Balloon-assisted enteroscopy - a scope is used in conjunction with a device called an overtube. This enables the doctor to look further into the small bowel where standard endoscopes cannot reach.

Crohn's Treatments

There is currently no cure for Crohn’s disease. The aim of treatment is to reduce inflammation that triggers your signs and symptoms.  Therapies include:

  • Medication
  • Nutrition therapy
  • Surgery


Nutrition Therapy: 

Your doctor may recommend a special diet given via a feeding tube (enteral nutrition) or nutrients injected into a vein (parenteral nutrition). This can help with nutrition and allow the bowel to rest. Bowel rest can reduce inflammation in the short term.


Surgery may be required if the symptoms of Crohn's disease cannot be controlled using medication alone. Surgery cannot cure Crohn's disease, but it can provide periods of remission. During surgery, the inflamed section of the digestive system is removed and the remaining part is reattached.

Common Side Effects of Crohn's Medications

  • A sore throat
  • A cough
  • Dizziness
  • Nausea
  • Vomiting
  • Bleeding and bruising
  • Increased risk of infection
  • Fever

Advice From The Pharmacist

  • Liver function should be monitored while on immunosuppressants.
  • If you develop a sore throat or fever speak with your GP as soon as possible.
  • Eat small meals regularly.
  • Try to identify foods that trigger your symptoms and avoid them.
  • Drink plenty of water.
  • Speak with a dietitian.
  • Smoking can trigger symptoms of Crohn’s disease – quitting can improve your symptoms.

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