Complications

Crohn's disease may lead to one or more of the following complications:

• Bowel obstruction. Crohn's disease can affect the entire thickness of the intestinal wall. Over time, parts of the bowel can scar and narrow, which may block the flow of digestive contents. You may require surgery to remove the diseased portion of your bowel.
• Ulcers. Chronic inflammation can lead to open sores (ulcers) anywhere in your digestive tract, including your mouth and anus, and in the genital area (perineum).

• Fistulas. Sometimes ulcers can extend completely through the intestinal wall, creating a fistula — an abnormal connection between different body parts. Fistulas can develop between your intestine and your skin, or between your intestine and another organ. Fistulas near or around the anal area (perianal) are the most common kind.

  When fistulas develop in the abdomen, food may bypass areas of the bowel that are necessary for absorption. Fistulas may form between loops of bowel, in the bladder or vagina, or through the skin, causing continuous drainage of bowel contents to your skin.

  In some cases, a fistula may become infected and form an abscess, which can be life-threatening if not treated.

• Anal fissure. This is a small tear in the tissue that lines the anus or in the skin around the anus where infections can occur. It's often associated with painful bowel movements and may lead to a perianal fistula.
• Malnutrition. Diarrhea, abdominal pain and cramping may make it difficult for you to eat or for your intestine to absorb enough nutrients to keep you nourished. It's also common to develop anemia due to low iron or vitamin B-12 caused by the disease.
• Colon cancer. Having Crohn's disease that affects your colon increases your risk of colon cancer. General colon cancer screening guidelines for people without Crohn's disease call for a colonoscopy every 10 years beginning at age 50. Ask your doctor whether you need to have this test done sooner and more frequently.
• Other health problems. Crohn's disease can cause problems in other parts of the body. Among these problems are anemia, skin disorders, osteoporosis, arthritis, and gallbladder or liver disease.

• Medication risks. Certain Crohn's disease drugs that act by blocking functions of the immune system are associated with a small risk of developing cancers such as lymphoma and skin cancers. They also increase risk of infection.

  Corticosteroids can be associated with a risk of osteoporosis, bone fractures, cataracts, glaucoma, diabetes and high blood pressure, among other conditions. Work with your doctor to determine risks and benefits of medications.

• Blood clots. Crohn's disease increases the risk of blood clots in veins and arteries.