Crohn’s Disease

Crohn’s disease is a chronic inflammatory condition of the digestive tract.

Overview

Crohn’s disease is a chronic condition in which abnormal reactions of the immune system cause inflammation in the digestive tract. It most commonly affects the small intestine and the beginning of the large intestine. However, the disease may affect any part of the digestive tract, from the mouth to the anus.

Studies show that Crohn’s disease has become more common in the United States and other parts of the world, though experts do not know the reason for this increase. When given proper medical care, many people who have Crohn’s disease are able to lead long and productive lives.

Signs and Symptoms

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 is called a flare. In between flares, most people have periods of remission when symptoms disappear. Periods of remission can last for weeks or years.

The most common symptoms of Crohn’s disease are diarrhea, cramping and pain in the abdomen, and weight loss. Symptoms may vary depending on the location and severity of the inflammation.

Other symptoms include:

  • Eye redness or pain
  • Feeling tired
  • Fever
  • Joint pain or soreness
  • Nausea, loss of appetite, or vomiting
  • Skin changes, such as red, tender bumps under the skin or a rash
  • Rectal bleeding

Related Health Effects

Crohn’s disease may lead to complications that develop over time. These include:

  • Anemia: Crohn’s disease may lead to more than one type of anemia, including iron-deficiency anemia, anemia of inflammation or chronic disease, or vitamin B12 deficiency anemia.
  • Bone problems: Crohn’s disease and corticosteroids used to treat it may lead to low bone mass, known as osteopenia or osteoporosis.
  • Growth and development problems in children: Problems may include gaining less weight than normal, slowed growth, short stature, or delayed puberty.
  • Malnutrition: This is a condition in which you do not get enough vitamins, minerals, and other nutrients needed to be healthy.

Other serious complications that may require hospitalization or surgery include:

  • Intestinal obstruction: A partial or total blockage of the movement of food, fluid, air, or stool through the intestines
  • Fistulas: Abnormal passages or tunnels between two organs, or between an organ and the outside of the body, which may become infected
  • Abscesses: Painful, swollen, pus-filled pockets of infection
  • Anal fissures: Small tears in the anus that may cause itching, pain, or bleeding
  • Ulcers: Open sores in the mouth, intestines, anus, or perineum.

Inflammation outside the digestive tract can cause:

  • Certain types of arthritis in joints
  • A form of liver disease called primary sclerosing cholangitis (PSC)
  • Kidney stones

People with Crohn’s disease also commonly report stress, depression, and anxiety.

Cancer Risk

People with Crohn’s disease may develop cancer of the small bowel or large intestine. The risk is higher with longer duration of disease, a personal history of PSC, or a family history of colorectal cancer. People with Crohn’s disease in the small intestine may be more likely to develop small intestine cancer, but the risk is low.

Causes and Risk Factors

Doctors are not sure what causes Crohn’s disease. Experts think the following factors may play a role.

Abnormal Immune Reaction

One possible cause is an abnormal reaction of the body’s immune system, which happens when the immune system attacks bacteria that tend to live in the intestines without normally causing harm. This immune system response causes inflammation in the digestive tract. Abnormal immune reactions can be triggered by the environment, genes, or by changes in the microbes that live in the digestive tract, known as the gut microbiome.

Microbiome

The microbiome is the microbes in the digestive tract, including bacteria, viruses, and fungi. These microbes are not normally harmful to the body, but rather help with digestion. Studies have found differences between the microbiomes of people who have inflammatory bowel disease and those who don’t. Researchers are still studying the relationship between the microbiome and inflammatory bowel disease.

Environment and Lifestyle

Experts think your environment and daily habits may play a role in Crohn’s disease. For example, research has shown smoking may double your chance of developing the illness.

Genes

Crohn’s disease sometimes runs in families. Research has shown that having a parent or sibling with Crohn’s disease may increase the likelihood of developing the disease.

Demographics

Crohn’s disease can develop in people of any age or race, but is more likely to develop in people of Jewish descent.

Prevention Guidance

Researchers have not found that specific foods cause or worsen Crohn’s disease symptoms. However, studies suggest that consuming healthy foods and drinks may lower the risk of developing inflammatory bowel disease.

Diagnosis

Crohn’s disease is frequently diagnosed in people between the ages of 18 and 30, but it may be diagnosed at any age. To diagnose Crohn’s disease, doctors review medical and family history, perform a physical exam, and order medical tests. Tests help confirm the diagnosis, find out how severe the inflammation is, where it is located, and rule out other health problems that may cause similar symptoms, such as infections, irritable bowel syndrome, or ulcerative colitis.

Medical and Family History

Your doctor will ask about your symptoms, your medical history, and any medicines you take. Your doctor will also ask about lifestyle factors, such as smoking, and about your family history.

Physical Exam

During a physical exam, a doctor most often:

  • Checks for bloating in the abdomen
  • Listens to sounds within the abdomen using a stethoscope
  • Presses on the abdomen to feel for tenderness or masses
  • Performs a full-body exam to check for weight loss and inflammation in other parts of the body

Lab Tests

Blood tests may check for:

  • Fewer than normal red blood cells, which may indicate anemia
  • Higher than normal white blood cell count, which may indicate inflammation or infection
  • Elevated c-reactive protein levels, which may indicate inflammation

Stool tests look for inflammation and rule out certain infections.

Endoscopy

Endoscopy tests are the most accurate way to diagnose Crohn’s disease and rule out other health problems. During an endoscopy, doctors use a long, flexible, narrow tube with a light and tiny camera on one end, called an endoscope, to view inside the gastrointestinal (GI) tract. Doctors may take biopsies during endoscopy tests to help diagnose Crohn’s disease.

Endoscopy tests include:

  • Colonoscopy, which doctors use to see inside the rectum, colon, and ileum
  • Enteroscopy, which doctors use to see inside the small intestine
  • Upper GI endoscopy, which doctors use to see inside the esophagus, stomach, and duodenum

Imaging Tests

Doctors may order imaging tests, including:

  • Computed tomography (CT) scans, which use a combination of x-rays and computer technology to create images
  • Magnetic resonance imaging (MRI), which takes pictures of the body’s internal organs and soft tissues without using x-rays
  • Upper small bowel with follow through series, which uses x-rays and a contrast material to view the upper GI tract, including the small intestine

Treatment and Management

There is currently no cure for Crohn’s disease. Doctors treat Crohn’s disease with medicines and surgery. The goals of treatment are to lower inflammation in the intestines, prevent flares of symptoms, and keep people in remission.

Medicines

Many people with Crohn’s disease need medicines. Which medicines a doctor prescribes depends on symptoms, where Crohn’s disease is causing inflammation, and other factors.

Crohn’s disease medicines include:

  • Corticosteroids
  • Immunosuppressants
  • Biologics
  • Kinase inhibitors, which doctors may prescribe for Crohn’s disease when it doesn’t respond to other medicines

Doctors may also recommend the following to manage symptoms and complications:

  • Acetaminophen for mild pain
  • Antibiotics to prevent or treat complications that involve infection, such as abscesses and fistulas
  • Loperamide to help slow or stop severe diarrhea, though only for short periods and not when intestinal inflammation is high, because it may increase the chance of developing megacolon
  • Medicines to treat inflammation in joints, eyes, or skin
  • Calcium and vitamin D supplements or medicines to prevent or slow bone loss and osteoporosis
  • Warm baths and ointments to treat anal fissures

Avoid taking nonsteroidal anti-inflammatory drugs (NSAIDs) to treat pain because they can make symptoms worse. For safety reasons, talk with your doctor before using dietary supplements or any complementary or alternative medicines or practices.

Bowel Rest

If hospitalized with complications from Crohn’s disease, you may need to rest the bowel for a few days to several weeks. Bowel rest may involve drinking only certain liquids or not eating or drinking anything. During bowel rest, a doctor may provide nutrients through a liquid drink, a feeding tube inserted into the stomach or small intestine, or a special tube inserted into a vein in the arm. In most cases, the intestines will heal during bowel rest.

Surgery

Even with medicines, many people will need surgery to treat their Crohn’s disease. Between 30% and 55% of people with Crohn’s disease will require surgery within 10 years after diagnosis. Surgery will not cure Crohn’s disease, but it can treat complications and improve symptoms.

Doctors most often recommend surgery to treat:

  • Fistulas
  • Abscesses
  • Cancer
  • Dysplasia, or precancerous cells that increase the risk for developing colorectal cancer
  • Life-threatening bleeding
  • Intestinal obstructions caused by scarring
  • Inflammation and symptoms that don’t improve or stop after treatment with medicines

Types of surgery include:

  • Small bowel resection: Surgery to remove part of the small intestine, which may be needed for an intestinal obstruction or severe Crohn’s disease in the small intestine
  • Strictureplasty: Surgery to bypass obstructions caused by scarring
  • Large bowel resection: Surgery to remove part of the large intestine, which may be needed for an intestinal obstruction, a fistula, or severe Crohn’s disease in the large intestine
  • Proctocolectomy and ileostomy: Surgery to remove the entire colon and rectum. In an ileostomy, surgeons bring the final section of the small intestine, called the ileum, through the abdominal wall and create a stoma, a surgical connection between an internal organ and the skin on the outside of the body. After an ileostomy, waste passes through the stoma, and the person wears a removable ostomy pouch to collect the waste. This stoma is permanent.

Living With Crohn’s Disease

Nutrition

Crohn’s disease can affect nutrition in several ways. Symptoms may cause some people to lose their appetite and eat less. Inflammation in the small intestine may cause the body to absorb fewer nutrients. Certain medicines and surgery used to treat Crohn’s disease may also cause the body to absorb fewer nutrients.

Depending on your symptoms and the medicines you take, your doctor may recommend changes to what you eat and drink. Your doctor may also recommend dietary supplements if your body does not absorb enough nutrients. Getting the right amount of nutrients may help prevent complications such as malnutrition and problems with growth and development in children

Nutrition supplements may be recommended especially for children whose growth has slowed. For some people, nutrition is given intravenously through a small tube in the arm.

Talk with your doctor about any foods that seem related to your symptoms. 2Your doctor may suggest keeping a food diary to help identify foods that seem to make symptoms worse. And since the microbiome is believed to be involved in Crohn’s disease, doctors may recommend eating more fruits and vegetables to promote the growth of healthy bacteria in the gut.

Managing Cancer Risk

Due to the increased risk of certain cancers in people with Crohn’s disease, doctors may recommend starting colorectal cancer screening 8 to 10 years after diagnosis, with repeat screening every 1 to 5 years. People with Crohn’s disease and PSC may need screening every year, starting at diagnosis.

Find Clinical Trials

Clinical trials uncover better ways to prevent, diagnose, treat, and understand diseases and conditions. To ensure results apply to everyone, volunteers of all ages, sexes, and backgrounds, including both healthy individuals and those with specific medical conditions, are needed. Find clinical trials on Crohn’s disease.

Community Support

The following resources offer information and support for people with Crohn’s disease and their families:

Note: This resource list is for informational purposes only. It is not comprehensive, and an organization’s inclusion does not constitute an endorsement by NIH.  

Research Information

The National Institutes of Health (NIH) is the largest public funder of biomedical research in the world. NIH invests most of its budget in medical research seeking to enhance life and to reduce illness and disability. NIH-funded research has led to breakthroughs and new treatments helping people live longer, healthier lives, and building the research foundation that drives discovery.  

NIH conducts and supports clinical trials in many diseases and conditions, including digestive diseases. These trials look to find new ways to prevent, detect, or treat disease and improve quality of life.

NIH-supported researchers are studying many aspects of Crohn’s disease and other types of inflammatory bowel disease, such as

  • Diet and the microbiome’s effect on Crohn’s disease
  • Genes associated with inflammatory bowel disease in African Americans
  • The immune system and how it controls inflammation in the digestive tract in people with inflammatory bowel disease
  • New treatments for Crohn’s disease

NIH-supported research efforts include the IBD Genetics Consortium (IBDGC), established in 2002 to identify genes that make some people more likely to develop IBD. The IBDGC, in collaboration with the International IBD Genetics Consortium, has enrolled thousands of people with inflammatory bowel disease and identified about 200 regions of the human genome associated with the risk of inflammatory bowel disease. NIH has also supported studies through the NIH Integrative Human Microbiome Project, which have examined the relationship between the microbiome and inflammatory bowel disease.

Find NIH-funded research projects using NIH RePORTER, a searchable database of current and past research projects supported by NIH and other federal agencies.