IBD Services: Crohn's Disease

Crohn's disease, which affects an estimated 500,000 to 700,000 Americans, is an inflammatory bowel disease (IBD) that causes swelling and irritation of the small intestine, usually the lower part known as the ileum. However, it can affect any part of the digestive tract.

Crohn's is a chronic disease characterized by periods of remission and flare-ups accompanied by extreme abdominal pain and diarrhea. In severe cases, it can lead to intestinal blockage and ulcerations that may require surgical intervention.

It differs from ulcerative colitis in that the inflammation can extend deep into the lining of the entire digestive tract. In ulcerative colitis, only the colon, or large intestine, is affected.

For more information about Crohn's disease or to schedule a consultation, please call us at 888-717-4463 or complete our online appointment request form › 

Risk factors

Although the causes of Crohn's disease are not well understood, recent research suggests that several factors may contribute to the disease and the worsening of symptoms, including:

  • Age
Crohn's disease affects men and women equally, and usually occurs in adolescents and adults between the ages of 15 and 35, with a second peak between the ages of 50 and 70.
  • Genetics
Crohn's tends to run in families.
  • Smoking
Smoking raises your risk of developing the condition. If you do develop it, smoking can make symptoms worse.
  • Environmental factors
Crohn's is more common in developed countries, urban areas and northern climates.
  • Stress
Stress does not directly cause Crohn's disease, but it can make symptoms worse or trigger flare-ups.
  • Diet

Diet does not cause Crohn's, but limiting dairy, fat and fiber can help ease your symptoms.


Symptoms of Crohn's disease vary, as does the severity, which makes it difficult to diagnose. Inflammation of the ileum, known as ileitis, can be caused by a variety of other diseases.

The most common symptoms of Crohn's disease are abdominal pain, primarily on the lower right side, and diarrhea. Other symptoms may include:
  • Anemia, caused by bleeding
  • Fatigue
  • Fever
  • Mouth sores
  • Rectal bleeding
  • Weight loss

People with Crohn’s disease often have problems with their immune systems, but it is not known whether that is a cause or a result of the disease. Other complications can include:
  • Abscesses
  • Anal fissures
  • Arthritis
  • Bowel obstructions
  • Fistulas
  • Kidney stones
  • Malnutrition
  • Eye inflammation
  • Osteoporosis
  • Skin rashes
  • Ulcers


UC Irvine Health is home to the only comprehensive IBD program in the region. Our physicians are the experts in diagnosing and treating Crohn's disease. As a university medical center, we have access to state-of-the-art diagnostic equipment and techniques, as well as the latest research.

To ensure an accurate diagnosis, our physicians perform a series of physical exams and tests, including:
  • Blood test
  • Colonoscopy
  • Endoscopy
  • Radiologic imaging
  • Stool test

Learn more about how our IBD specialists diagnose Crohn's disease and ulcerative colitis ›


The treatment of Crohn's disease depends on the location of the disease and its severity. There is no cure, but treatment can help manage the symptoms and make recurrences less frequent.

Treatments may include:

  • Medications

These include a variety of medications aimed at reducing and eliminating inflammation.

  • Surgery
When symptoms do not respond to medications or when further complications of the disease occur, surgery may be necessary. Complications of Crohn's that may require surgery include blockages, bleeding and perforations of the digestive tract.

View our Crohn's disease FAQ ›

If you or a loved one think you may have an inflammatory bowel disease, our IBD team can help. To make an appointment with one of our gastrointestinal specialists, call 888-717-4463.