Crohn’s Disease Symptoms

Medically reviewed by Kenneth R. Hirsch, MD on June 19, 2014Written by Anthony Watt

Symptoms of Crohn's Disease Overview

Crohn's disease causes a variety of symptoms that can vary from mild to severe. Most symptoms are the result of inflammation in the gastrointestinal tract, most commonly in the lower part of the small intestine (the ileum) or parts of the large intestine (the colon).

Inflammation is an immune response. It’s one way to destroy an infecting virus or bacteria, or other foreign object perceived as not self. In the case of autoimmune diseases—such as in Crohn’s—the immune system either overreacts or mistakenly reacts and attacks normal components of a person’s body.

The cause of Crohn's is not known for certain. Experts believe the immune system may be overreacting either to a real threat from an unidentified virus or bacteria or to a part of the benign bacteria that exist in everyone's gastrointestinal system. It’s also possible that the body perceives the food it’s digesting as a threat and is mistakenly attempting to protect itself.

Common Symptoms of Crohn’s Disease

The symptoms of Crohn’s disease may be mild or severe. They may come on gradually or appear suddenly. The most common symptoms are:

  • bloody stools
  • diarrhea
  • loss of appetite
  • abdominal pain and cramping
  • unwanted weight loss
  • fever

About 33 percent of patients have fissures and fistulas (tears and tunnels) around the anus. This may be the first or most noticeable symptom.

In children, the first symptoms might be:

  • arthritis
  • fever of unknown origin
  • anemia
  • delayed growth

Other Symptoms of Crohn’s Disease

If you have Crohn’s disease you may experience:

  • vomiting
  • rash
  • eye inflammation
  • arthritis
  • mouth sores
  • fatigue
  • anemia

Symptoms Associated With Different Types of Crohn’s Disease

Crohn’s disease is classified into types depending on where it occurs. Symptoms may vary depending on what part of the GI tract is affected.


Ileocolitis is the most common form of Crohn’s disease. Approximately 45 percent of Crohn’s cases are Ileocolitis (Merck). It affects the ileum (the end of the small intestine) and the colon (the large intestine). The symptoms are:

  • diarrhea
  • pain or cramping in the middle or lower right abdomen
  • severe weight loss


Ileitis affects only the ileum. This is about 35 percent of cases (Merck). Symptoms include:

  • diarrhea
  • pain or cramping in the middle or lower right abdomen
  • in severe cases—fistulas (holes) or inflammatory abscess (infection) in the lower right abdomen

Crohn’s Granulomatous Colitis

This type of colitis affects only the colon. This form makes up about 20 percent of Crohn’s cases (Merck). Skin lesions and joint pain are more common with this type of Crohn’s disease. Other symptoms include:

  • diarrhea
  • rectal bleeding
  • abscesses, fistulas, and ulcers around the anus

Gastroduodenal Crohn’s Disease

This form of the disease affects the stomach and the beginning of the small intestine (the duodenum). This is rare. Symptoms include:

  • gastric outlet obstruction
  • loss of appetite
  • weight loss
  • nausea
  • vomiting


Jejunoileitis affects the upper half of the small intestine (the jejunum) and the ileum. This form occurs only occasionally. The symptoms include:

  • abdominal pain and cramps after meals
  • diarrhea
  • fistulas (in severe cases)
CMS Id: 15146