Crohn’s Causes

While its exact causes are unknown, what is known is that Crohn’s disease is a chronic, or ongoing, inflammatory bowel disease (IBD) that primarily affects the digestive or gastrointestinal (GI) tractCollectively referring to the mouth, esophagus, stomach, small and large intestines, and anus.. Crohn’s inflammation can develop anywhere from the mouth to the anus, and symptoms may vary depending on what part of the GI tract is inflamed. You may experience symptoms that occur outside the GI tract, affecting the eyes, skin and joints. Crohn’s is not contagious, nor is it caused by something you may have done or eaten.

Crohn’s appears to be a result of an interaction of factors

  • Heredity: You may inherit genes that make you more susceptible to developing Crohn’s
  • The immune system: When triggered, it affects the gastrointestinal tract, causing inflammation that contributes to symptoms
  • Environmental factors: Bacteria, a virus, or some unidentified factor in the environment that triggers an abnormal immune response

Foreign substances (antigens) in the environment may also be a cause of inflammation, or they may stimulate the body’s defenses to produce inflammation that continues without control.

Crohn’s disease appears to be a result of different factors: Heredity, the immune system, and environmental factors

Crohn’s is believed to be an overreaction of the immune system.

Researchers believe people with Crohn’s experience an overactive immune response. As a result, the intestines become raw and inflamed (red and swollen)—chronically. This continuous, damaging inflammation occurs in the digestive tract and leads to Crohn’s symptoms.

How your immune system works

  • The immune system is a complex network of cells that interact with each other to defend the body against foreign invaders
  • Circulating white blood cells patrol for foreign invaders, such as bacteria or viruses, “non-self” cells, which are considered dangerous
  • When the white blood cells find these invaders, they trigger an immune response called “inflammation” that results in the destruction and removal of the foreign substances

Inflammation: Your immune system’s weapon

  • Inflammation is your body’s weapon against foreign invaders, such as bacteria and viruses. White blood cells release molecules called “cytokines”—chemical messengers that promote inflammation
  • Inflammation helps the body limit the effects of the invader so it does not spread. Once the foreign invader is destroyed, inflammation goes away
  • Redness, swelling, and pain are all signs that inflammation is occurring in your body—and in Crohn’s disease, this inflammation is chronic (ongoing) unless controlled with an effective treatment plan

Whom does Crohn’s disease affect?

While Crohn’s disease most often starts between the ages of 15 and 35, it can affect people of any age.

Crohn’s disease affects men and women equally, and it appears to be more common in people in developed countries and among the Ashkenazi Jewish population.

Crohn’s disease affects men and women equally

Understand Your Inflammation

Learn how it can play a role in your symptoms.

See Inside Inflammation

Crohn’s Tests and Diagnosis

Find out what tests are used to get diagnosed as well as for ongoing follow-ups.

Learn More

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