Question: What is Crohn’s disease?
Answer: Crohn’s disease is a chronic disease in which abnormal reactions of the immune system cause inflammation in your digestive tract. Most commonly, Crohn’s disease affects your small intestine and the beginning of your large intestine. However, the disease may affect any part of your digestive tract, from your mouth to your anus.

Crohn’s disease is an inflammatory bowel disease (IBD). Ulcerative colitis and microscopic colitis are other common types of IBD.

Crohn’s disease most often begins slowly and may get worse over time. Symptoms can range from mild to severe. When people have symptoms, it’s called a flare. In between flares, most people have periods of remission—times when symptoms disappear. Periods of remission can last for weeks or years. The goal of treatment is to keep people in remission long term.
Question: How common is Crohn’s disease?
Answer: Researchers estimate that 1 million people in the United States have Crohn’s disease.1 Studies show that Crohn’s disease has become more common in the United States and other parts of the world. Experts do not know the reason for this increase.
Question: Who is more likely to develop Crohn’s disease?
Answer: Crohn’s disease can develop in people of any age or race, but is more likely to develop in people who

are between the ages of 20 and 292
have a family member, most often a sibling or parent, with IBD
are of Jewish descent2
smoke cigarettes
Question: What are the complications of Crohn’s disease?
Answer: Crohn’s disease may lead to complications that develop over time. Complications may include

anemia, a condition in which you have fewer red blood cells than normal. Crohn’s disease may lead to more than one type of anemia, includingiron-deficiency anemia,anemia of inflammation or chronic disease, orvitamin B12 deficiency anemia.
bone problems. Crohn’s disease andcorticosteroidsused to treat the disease may lead tolow bone mass, known as osteopenia orosteoporosis.
problems with growth and development in children. Problems may include gaining less weight than normal, slowed growth, short stature, or delayedpuberty.
malnutrition, a condition in which you don’t get enough of the vitamins, minerals, and other nutrients you need to be healthy.

The inflammation of Crohn’s disease may lead to serious complications, which could require being treated at a hospital or surgery. Serious complications include

intestinal obstruction, a partial or total blockage of the movement of food, fluid, air, orstoolthrough your intestines.
fistulas, which are abnormal passages or tunnels between two organs, or between an organ and the outside of your body. Fistulas may become infected.
abscesses, which are painful, swollen, pus-filled pockets of infection.
anal fissures, which are small tears in your anus. Anal fissures may cause itching, pain, or bleeding.
ulcers, or open sores in your mouth, intestines, anus, orperineum.

Health problems affecting other parts of the body

Some people with Crohn’s disease also have inflammation in parts of the body other than the digestive tract, including the

joints, causing certain types of arthritis
skin, such as a rash that can be painful
eyes, including irritation
liverandbile ducts, causing conditions such asprimary sclerosing cholangitis (PSC)
kidneys, including development ofkidney stones
lungs, which if severe can lead to difficulty breathing

People with Crohn’s disease also commonly report stress, depression, and anxiety. Stress may change the microbiome in the digestive tract, which can worsen the symptoms of Crohn’s disease.

Colorectal and small intestine cancer

If you have Crohn’s disease in your large intestine, you are more likely to develop colorectal cancer. Your risk is higher if you’ve had Crohn’s disease for a longer time. Your risk is also higher if you have PSC or a family history of colorectal cancer.

Your doctor may recommend a colonoscopy to screen for colorectal cancer. Screening is testing for diseases when you have no symptoms. Screening can check for colorectal cancer or precancerous cells, known as dysplasia. Diagnosing cancer early can improve chances for recovery.

For people with Crohn’s disease in the large intestine, doctors most often recommend starting colorectal cancer screening 8 to 10 years after diagnosis. Doctors may recommend repeat screening every 1 to 5 years.3,4 If you have Crohn’s disease and PSC, your doctor may recommend screening every year, starting at diagnosis.2

If you have Crohn’s disease in your small intestine, you may be more likely to develop small intestine cancer, but the risk is very low.