CD is one of a group of disorders collectively referred to as inflammatory bowel disease (IBD). CD causes painful inflammation in your digestive tract and usually occurs in the lower part of the small intestine or colon.
While the direct cause of CD is unknown, here's what we do know: First, you may be more likely to experience CD if it's part of your family's medical history. Second, CD symptoms  begin when your immune system attacks healthy cells in your body , for reasons we do not yet understand.
Normally, the immune system (the body's natural defense system), protects your body from bacteria, viruses and other foreign agents. When you have CD, your immune system incorrectly targets your gastrointestinal tract. This causes inflammation—leading to the symptoms and flares usually experienced with CD.
Approximately 500,000 Americans have CD, which affects men and women equally.
What's more, CD:
Hear from these actual patients with moderately to severely active CD who didn't respond well to other therapies and were treated with REMICADE®. Individual results may vary.
Symptoms may range from mild to severe. They tend to show up after meals, with pain usually centered at or below the navel, often in the lower right section of the abdomen.
People with CD have periodic disease flares (when the disease is active) followed by periods of remission (times when there are few or no symptoms).
The most common symptoms of CD include:
Other symptoms may include:
Fistulas are another common symptom. Fistulas occur when the inflammation and ulcers caused by CD break through the intestinal wall and form an abscess (or a tunnel) outside of it.
Designed by experts at McMaster University, the SIBDQ does more than simply ask about your physical symptoms—it measures the impact of those symptoms on your social and emotional well-being.
Answering the SIBDQ can help you and your doctor determine how your symptoms affect your daily life. You should fill out the SIBDQ every 2 months or each time you visit your doctor so he or she can determine whether your current medication is controlling your symptoms, and, if necessary, recommend other treatment options.
Although there is no cure for CD, the sooner CD is diagnosed, the sooner you may be able to gain control of your symptoms  and possibly induce remission.
To confirm a diagnosis—and to rule out other conditions that can cause similar symptoms—your physician will probably perform a complete physical exam and order medical tests. There is no single test that can confirm the diagnosis of CD.
Diagnostic tests may include:
It's important to discuss all your symptoms with your doctor to determine the appropriate tests.
CD and ulcerative colitis (UC) are classified as types of IBD, a term used to describe inflammatory conditions affecting the digestive (or gastrointestinal [GI]) tract.
While CD and UC are both IBDs and have similar symptoms, there are a few distinct differences between the 2 conditions:
Despite these differences, in approximately 10% of cases, doctors are unable to confirm a diagnosis of either CD or UC. These cases are called indeterminate colitis.
Only your doctor can recommend a course of treatment after checking your health condition. REMICADE® (infliximab) can cause serious side effects such as lowering your ability to fight infections. Some patients, especially those 65 years and older, have had serious infections caused by viruses, fungi or bacteria that have spread throughout the body, including tuberculosis (TB) and histoplasmosis. Some of these infections have been fatal. Your doctor should monitor you closely for signs and symptoms of TB during treatment with REMICADE®.
Unusual cancers have been reported in children and teenage patients taking TNF-blocker medicines. Hepatosplenic T-cell lymphoma, a rare form of fatal lymphoma, has occurred mostly in teenage or young adult males with Crohn’s disease or ulcerative colitis who were taking REMICADE® and azathioprine or 6-mercaptopurine. For children and adults taking TNF blockers, including REMICADE®, the chances of getting lymphoma or other cancers may increase.
You should discuss any concerns about your health and medical care with your doctor.
What should I tell my doctor before I take REMICADE®?
You should let your doctor know if you have or ever had any of the following:
Also tell your doctor if you:
What should I watch for and talk to my doctor about before or while taking REMICADE®?
The following serious (sometimes fatal) side effects have been reported in people taking REMICADE®.
You should tell your doctor right away if you have any of the signs listed below:
You are encouraged to report negative side effects of prescription drugs to the FDA.
Visit www.fda.gov/medwatch, or call 1-800-FDA-1088.