In this article, we explore Crohn's disease and its causes, risk factors, and prevalence.
We also describe the differences between Crohn's, ulcerative colitis, and irritable bowel syndrome (IBS). We then look into the complications, diagnosis, treatment, and costs of treating Crohn's disease.
What is Crohn's disease?
Crohn's disease is a condition that requires lifelong management.
Crohn's is a type of inflammatory bowel disease (IBD).
Symptoms of Crohn's disease can vary considerably among people, but they typically include diarrhea and abdominal pain and cramping.
Other symptoms can include:
- weight loss
- a loss of appetite or nausea
- blood in stools
- red, sore eyes
- joint pain
- red patches of tender skin
Symptoms of Crohn's disease can come and go and may sometimes disappear for weeks or even months.
Doctors describe periods of few or no symptoms as remission. When symptoms return or suddenly get worse, they refer to it as a flare-up or relapse.
There is no cure for Crohn's disease. The aim of treatment is to relieve symptoms, achieving and maintaining remission.
Causes and risk factors
Doctors have not yet identified a specific cause of Crohn's disease. The general consensus among researchers is that the disease results from a malfunctioning immune system.
According to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), bacteria in the digestive tract may trigger the immune system to attack healthy tissues, which leads to inflammation.
Crohn's disease can also run in families and appears to be more common in people who have a close relative with the condition.
Research into risk factors for Crohn's disease is ongoing. Some experts think a diet high in dairy, sugar, and processed food may increase a person's risk. Depression and anxiety may also play a role in developing the condition.
NIDDK states that "Stress and eating certain foods do not cause Crohn's disease." However, they also point to research that suggests that stress and certain foods may trigger or worsen symptoms in some people.
Research indicates that other risk factors include:
- smoking cigarettes
- having an appendectomy
- frequent use of certain medications, such as nonsteroidal anti-inflammatory drugs, antibiotics, and the birth control pill
According to research from 2013, more than 1.17 million adults in the United States had IBD. Of this group, around 565,000 had Crohn's disease and 593,000 had ulcerative colitis, which is another type of IBD.
Crohn's disease appears to be becoming more common in the U.S. and other parts of the world, according to NIDDK.
The Centers for Disease Control and Prevention (CDC) report that doctors diagnose 3.1–14.6 new cases of Crohn's per 100,000 person-years. They also note that IBD is more common in developed countries.
Anyone can develop Crohn's disease, but it is more common in younger people, particularly those between the ages of 20 and 29 years.
Crohn's disease vs. ulcerative colitis
Crohn's disease and ulcerative colitis both affect the digestive system.
Crohn's disease and ulcerative colitis are both types of IBD, and they share many symptoms and risk factors. Treatment options for the two conditions can also be similar.
However, there are also some important differences, for example:
- Crohn's disease can affect any part of the digestive tract, but ulcerative colitis only develops in the colon and rectum.
- Crohn's disease tends to cause patches of inflammation with areas of healthy tissue in between, whereas ulcerative colitis causes uninterrupted inflammation along the colon.
- Crohn's disease can affect all the layers of the bowel wall, but ulcerative colitis only occurs in the inner lining of the colon.
Some research suggests that ulcerative colitis is slightly more common than Crohn's disease in North America.
IBD vs. IBS
IBD and IBS both affect the digestive system, and they can cause similar symptoms, such as diarrhea and abdominal discomfort.
However, they are different conditions with different causes and treatments.
While IBD can cause lasting damage to the intestines, IBS does not cause inflammation or any visible signs of intestinal injury.
Some key differences between IBD and IBS include:
- IBD is an autoimmune condition, whereas IBS results from changes in the way that the intestines contract and relax.
- The symptoms and complications of IBD tend to be more severe than those of IBS.
- Treatment of IBS typically focuses on lifestyle and dietary changes, whereas people with IBD often need to take medications that help reduce inflammation in the digestive tract.
It is possible to have both IBD and IBS.
Crohn's disease can lead to a number of serious complications, particularly in people who do not receive treatment or if treatment is unsuccessful.
Potential complications of Crohn's disease can include:
- Abscesses. Infection in the digestive tract can lead to swollen, painful, and pus-filled areas called abscesses.
- Anal fissures. These are small tears or rips at the end of the anal canal, near the rectum. They can cause itching, bleeding, and pain.
- Intestinal obstruction. Severe inflammation can lead to partial or complete blockages that prevent the movement of food and waste through the intestines. These obstructions can be life-threatening and require immediate medical attention.
- Fistulas. If inflammation goes through the intestinal wall, abnormal tunnel-like structures (fistulas) can form between parts of intestines or between the intestines and other parts of the body.
- External inflammation. Beyond the digestive tract, Crohn's disease can cause inflammation in joints, the eyes, and the skin.
- Malnutrition. Diarrhea, a loss of appetite, and other symptoms of Crohn's can mean that a person is not eating and absorbing enough of the nutrients that they need to stay healthy.
- Ulcers. Open sores can develop anywhere along the digestive tract.
To diagnose Crohn's disease, a doctor typically asks about symptoms, medical history, and family history. They may then examine the abdomen to check for bloating and swelling.
Doctors often need to order more tests to help with their diagnosis. These tests may include:
- Blood tests. A healthcare professional will take a small sample of blood and analyze it for signs of inflammation, anemia, and other conditions.
- Stool tests. These require a person to provide a sample of their stool in a special container. Doctors use these samples to check for other conditions that can cause digestive issues.
- Endoscopy. An endoscope is a thin, flexible tube with a light and a camera on the end. A doctor uses this tool to check the inside of the digestive tract for signs of inflammation, either by inserting it down a person's throat or up through their anus.
- Imaging tests. These create pictures of the inside of a person's body and can include X-rays, MRI scans, and CT scans. A doctor can use the images to pinpoint and evaluate the severity of inflammation within the digestive tract.
A person can work with their doctor to develop a treatment plan for Crohn's disease.
There is currently no cure for people with Crohn's disease or IBD. However, a number of treatments can help:
- promote and sustain remission
- reduce inflammation
- prevent damage to the intestines
- stop flare-ups before they happen
The medications that a doctor prescribes depend on the type and severity of a person's symptoms and how well their Crohn's disease responds to other treatments.
Medications for Crohn's disease can include:
- steroid medications
- biologic therapies
These drugs can help reduce inflammation, limit the immune response, relieve symptoms, and treat infections.
Doctors may also suggest dietary changes and nutritional supplements to help relieve or prevent symptoms.
When complications occur or symptoms do not respond to medications, a person may require surgery.
According to NIDDK, research suggests that nearly 60 percent of people will need surgery within 20 years of a Crohn's disease diagnosis.
Costs of treatment
The cost of treating Crohn's disease can vary considerably, depending on symptoms, complications, and the type of treatment.
In general, treatment can be expensive. One study found that care for Crohn's disease in the U.S. can cost $25,282–$26,192 per year, per person.
The big cost-drivers of Crohn's treatment are surgery, biologic therapies, and hospitalization.
People with more severe inflammation and complications tend to pay the most for treatment. Research suggests that 2 percent of individuals with the highest costs account for around 34 percent of overall Crohn's disease treatment costs in the U.S.
Crohn's disease is a type of IBD that can cause digestive issues, such as diarrhea and a wide range of other symptoms.
Although it is a lifelong condition with no cure, successful treatment can help people achieve and maintain remission for years.
An important aspect of managing Crohn's disease is understanding the condition, what causes it, and how to handle symptoms.
For example, a person's diet does not cause their Crohn's disease, but eating more healthfully and avoiding certain foods can help reduce flare-ups. Keeping a food journal can help a person determine which foods soothe or trigger their symptoms.