Crohn’s disease usually occurs in the last part of the small intestine and the beginning of the colon. Sometimes it can show up in patches anywhere in the intestines though. If the irritation goes on for too long, it can cause damage. This damage can be scar which narrows the bowel. Also, the body can form a tunnel going from inside the bowel out to the surface. This is called a fistula and can attach the bowels to other body parts like the skin or bladder. When this happens, other problems can occur.

What are the signs and symptoms of Crohn’s disease?

Signs and symptoms can be mild or severe and can be different. It depends on the part of the digestive tract involved. Symptoms usually build over time but also can happen suddenly.

The most common symptoms of Crohn’s disease are:

• Diarrhea

  
  

• Pain and cramping in the abdomen (belly)

  
  

• Feeling tired

  
  

• Feeling the need to have a bowel movement

  
  

• Fever

  
  

• Weight loss

Other symptoms may include:

• Blood in the stool

  
  

• Drainage around the anus

  
  

• Joint pain

  
  

• Lack of hunger

  
  

• Nausea and vomiting

  
  

• Pain, redness, or swelling in the eyes

  
  

• Rashes

What are the risk factors for Crohn’s disease?

• Age: Most people get it are in their twenties, but it can happen at any age.

  
  

• Family history: If you have one parent with Crohn’s disease, odds of getting it are 7 to 10 percent. If both parents have it, the odds go up to 35 percent.

  
  

• Nonsteroidal anti-inflammatory drugs (NSAIDs): While medicines such as aspirin, ibuprofen and naproxen do not cause Crohn’s disease, they can worsen inflammation and make the disease worse.

  
  

• Race and ethnicity: White people and people of Eastern European Jewish (Ashkenazi Jewish) descent are at the highest risk.

  
  

• Smoking: Tobacco use doubles the risk of Crohn’s disease. It also increases the chances of having a more severe form that needs surgery.

  
  

• Location: People who live in more developed countries and cities are also at higher risk.

  
  

• Antibiotics: These can change the healthy bacteria living in the colon. These play a part in how the immune system is working in the intestines.

How is Crohn’s disease diagnosed?

Your doctor will hear your symptoms, medical history and risk factors. They will also do an exam looking for any signs. No one test for Crohn’s disease exists, but a mixture of tests can rule out other problems and make the diagnosis.

Tests that you may need:

• Blood tests: Look for signs of infection, anemia (low blood count), low vitamin levels and abnormal liver tests.

  
  

• Stool samples: Check for blood, inflammation or infections in the stool.

  
  

• CT scans or MRI imaging: X-rays that see parts of the digestive tract in more detail. Can also see other parts of the body too.

  
  

Barium x-rays: Also an x-ray that shows how the bowel is shaped and looks. Can be done by drinking a liquid or having it put inside your bowel with an enema.

Doctors may also use diagnostic procedures such as:

• Colonoscopy or flexible sigmoidoscopy: Using a thin, flexible tube with a lighted camera, your doctor looks at the inside lining of the colon. They can possibly see the lower end of the small intestine as well.

  
  

• Biopsy: Your doctor may perform this during a colonoscopy. A small tissue sample is taken and looked at under a microscope.

  
  

• Upper endoscopy: Also called an esophagogastroduodenoscopy (EGD), this procedure examines the upper part of the digestive tract.

  
  

• Capsule endoscopy: You swallow a pill containing a tiny camera. This takes pictures of the digestive tract. It then sends the pictures to a computer for your doctor to look at.

What are the Possible Complications?

Over time, Crohn’s disease may lead to serious complications, including:

Digestive Tract Complications:

• Anemia (due to iron, B12 deficiency, or chronic inflammation)

  
  

• Bone problems (osteopenia or osteoporosis, especially from steroid use)

  
  

• Growth issues in children (poor weight gain, delayed puberty, short stature)

  
  

• Malnutrition (lack of essential nutrients)

  
  

• Intestinal obstruction (blockage in the intestines)

  
  

• Fistulas (abnormal tunnels between organs or skin)

  
  

• Abscesses (painful, infected pus-filled pockets)

  
  

• Anal fissures (small, painful tears in the anus)

  
  

• Ulcers (sores in the mouth, intestine, or anal area)

Complications Outside the Digestive Tract:

• Joint inflammation (arthritis)

  
  

• Skin rashes

  
  

• Eye irritation

  
  

• Liver and bile duct conditions, such as primary sclerosing cholangitis (PSC)

  
  

• Kidney stones

  
  

• Lung inflammation

Crohn’s disease is also linked to increased levels of stress, anxiety, and depression, which can worsen symptoms by affecting the gut microbiome.

Risk of Cancer

Colorectal Cancer:

• People with Crohn’s disease in the large intestine have a higher risk of colorectal cancer, especially with long-term disease or family history.

  
  

• Colonoscopy screenings are typically recommended 8–10 years after diagnosis, and then every 1–5 years.

  
  

• If you also have PSC, screening may begin at the time of diagnosis and continue annually.

Small Intestine Cancer:

• Those with Crohn’s in the small intestine may have a slightly higher risk, though it remains very rare.

Important Reminder: This information is intended only to provide general guidance. It does not provide definitive medical advice. It is very important that you consult your doctor about your specific condition.

Crohn's Disease - American College of Gastroenterology