Inflammatory bowel disease is an umbrella term for a number of long-term conditions that involve inflammation of the digestive tract, or the gut.

According to the Crohn's and Colitis Foundation, inflammatory bowel disease (IBD) affects up to 1.6 million Americans. The majority of these people are diagnosed before age 30.

IBD is often confused with irritable bowel syndrome (IBS) but the two conditions are different. IBD is a more serious condition, which may lead to a number of complications including damage to the bowel and malnutrition.

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Ulcerative colitis and Crohn's disease combined affect up to 1.6 million Americans.

The two main types of IBD are ulcerative colitis and Crohn's disease.

Ulcerative colitis

This condition, which may affect up to 907,000 American people, causes inflammation of the large intestine (colon). There are different classes of ulcerative colitis depending on its location and severity:

  • Ulcerative proctitis: Inflammation is confined to the rectum. This tends to be the mildest form of ulcerative colitis.
  • Universal colitis or pancolitis: Inflammation affects the entire colon.
  • Proctosigmoiditis: Inflammation affects the rectum and lower end of the colon.
  • Distal colitis: Inflammation extends from the rectum and up the left colon.
  • Acute severe ulcerative colitis: A rare form that affects the entire colon and causes severe symptoms and pain.

Crohn's disease

Crohn's disease can affect any part of the digestive tract - from mouth to anus - although the most commonly affected areas are the final section of the small intestine and the colon.

Crohn's disease may affect up to 780,000 Americans. The disease can occur at any age, but it is most common in those aged 15 to 35.

While ulcerative colitis and Crohn's disease are the two major forms of classic IBD, other types include lymphocytic colitis and collagenous colitis. If doctors are unable to distinguish between the two main types of IBD, the condition is classed as indeterminate colitis.

It is not known what causes IBD, but many experts believe several factors may play a role:

  • Immune function: IBD may result when an abnormal immune system response to bacteria, viruses, or food particles, triggers an inflammatory reaction in the gut.
  • Genetics: Links have been discovered between IBD and certain gene mutations. Up to 20 percent of those with ulcerative colitis have a close relative with IBD, but no specific pattern to heredity has been established.
  • Bacteria or viruses: Research has linked both E.coli and enteroviruses to Crohn's disease.
  • Environmental: Factors such as smoking, oral contraceptives, diet, breastfeeding, vaccinations, antibiotics, and others have been investigated as potential causes.

Risk factors

A number of risk factors have also been identified in the onset of IBD, including:

  • Age: most people are diagnosed before age 30.
  • Ethnicity: Caucasians and Ashkenazi Jews are at higher risk than others.
  • Genetics: People with a close relative with IBD are at higher risk.
  • Location: People living in urban areas and in industrialized countries are more likely to be diagnosed with IBD.
  • Medications: Use of certain medications, such as isotretinoin or nonsteroidal anti-inflammatory medications may increase the risk.
  • Smoking: Smokers are at higher risk of developing Crohn's disease, although ulcerative colitis mainly affects nonsmokers.

an infographics showing the effects on the body of IBD

Symptoms vary according to the location and severity of the disease, as well as the type of disease. The following symptoms are common to both types of IBD:

  • blood in the stool
  • diarrhea
  • fatigue
  • fever
  • lack of appetite
  • nausea
  • painful or difficult bowel movements
  • a feeling that the bowels are not empty after a bowel movement
  • pus or mucus in the stool
  • stomach pain and cramps
  • vomiting
  • night sweats
  • weight loss

IBD may also be associated with symptoms that do not appear to be related to the digestive system, such as:

  • joint pain
  • canker sores in the mouth
  • inflammation of the eyes
  • skin disorders
  • irregular periods in females

Children with IBD can also experience impaired growth.

Those with IBD can experience periods where symptoms worsen - called flares or relapses - and periods with little or no symptoms, known as remission. Flares vary in their number, intensity, and duration.

The goal of treatment is to bring IBD into remission, and keep it there for as long as possible.


A number of complications are associated with IBD - some of which can be life-threatening. Possible complications of Crohn's disease include:

  • bowel obstruction
  • colon cancer
  • fistulas, abnormal tunnels in the gut
  • malnutrition

Possible complications of ulcerative colitis include:

  • colon cancer
  • fulminant colitis, where normal contractions of the intestinal wall stop temporarily
  • a hole or tear in the colon
  • strictures or narrowing of the colon
  • toxic megacolon, where swelling and trapped gas can lead to colon rupture, septicemia, and shock

In order to diagnose IBD, a doctor will take a full medical history before ordering one or more diagnostic tests. Types of tests used include:

  • stool sample
  • blood tests to test for anemia or infection
  • X-rays, if a serious complication is suspected
  • CT scan
  • MRI scans, to detect fistulas in the small intestine or anal area

Endoscopic procedures may also be used. A flexible probe with a camera attached is inserted through the anus. These procedures help uncover intestinal damage and allow the doctor to take a small sample of tissue to examine. Types of endoscopic procedures typically used include:

  • colonoscopy - to examine the entire colon
  • flexible sigmoidoscopy - to examine the last section of the colon
  • upper endoscopy - to examine the food pipe, stomach, and first part of small intestine

A capsule endoscopy is another option. This procedure requires a person to swallow a capsule that has a camera inside, which allows a doctor to examine the small intestine.

There is no cure for IBD. The goal of treatment is to reduce symptoms, achieve and maintain remission, and avoid associated complications. The most common available treatments are medications and surgery.


Doctors may prescribe drugs, beginning with the milder ones first and working up to more aggressive treatments.

  • Anti-inflammatory drugs: 5-ASA medications are typically the first line of defense against IBD symptoms. They reduce inflammation in the gut, and may help achieve and maintain remission.
  • Corticosteroids: Fast-acting anti-inflammatory steroids that may be prescribed if the milder class of anti-inflammatories aren't effective. They are only used to treat flares and should not be used long-term.
  • Immune suppressors: These work by preventing the immune system from attacking the bowel cells, leading to a reduction in inflammation. They can take up to 3 months to take effect, and cause a number of side effects such as increased susceptibility to infection.
  • Biologic therapies: Antibodies that target certain substances responsible for inflammation in the body.

In addition, other medications recommended for those with IBD can include:

  • antibiotics
  • antidiarrheal drugs
  • laxatives
  • vitamin and mineral supplements, for cases of nutritional deficiency associated with IBD


In some cases, surgery may be necessary to treat IBD symptoms and complications. Surgery may be recommended to widen a narrow bowel or remove fistulas.

People who have ulcerative colitis, may undergo surgery to remove the colon and rectum. Those with Crohn's disease may have surgery to remove certain portions of the intestines.


Certain dietary and lifestyle factors are thought to make IBD symptoms worse. Making positive changes in these areas can help manage symptoms, reduce flares, and even maintain remission.


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Keeping a daily food log can help identify which foods cause IBD symptoms.

Dietary measures that may be beneficial for those with IBD include:

  • keeping a food diary to track if certain symptoms are associated with certain foods
  • limiting the intake of dairy products
  • limiting the intake of high-fat foods
  • limiting or avoiding spicy foods, caffeine, and alcohol
  • limiting high-fiber foods, particularly if narrowing of the bowel is an issue
  • eating frequent small meals rather than several large ones
  • drinking plenty of water
  • taking vitamin and mineral supplements to prevent deficiencies


Many people with IBD say they experience more severe symptoms during stressful periods. Learning to manage stress may help reduce the number and severity of these types of flare-ups.

Stress management techniques include exercise, meditation, breathing exercises, progressive muscle relaxation, and engaging in hobbies and other enjoyable activities.


Smoking has been shown to negatively affect those with Crohn's disease. Not only is smoking a risk factor for developing the disease, but it also makes symptoms worse.

Some research has suggested that smoking may actually benefit those with ulcerative colitis but the health risks associated with smoking far outweigh any benefits.

Emotional support

IBD can have an emotional effect on those with the condition, especially in severe cases. Therefore, it is important to have a good network of supports among family and friends.

People with IBD might consider joining an IBD support group or attending counseling sessions, which they may find beneficial.


Because the exact cause of IBD is not yet known, it is difficult to know how best to prevent it.

The genetic factors associated with IBD are beyond a person's control but it is possible to reduce the risk by eating a healthful diet, quitting smoking, and exercising regularly.


Although there is no cure for IBD, it can be managed with medical interventions and lifestyle changes.

With effective treatment, approximately 50 percent of those with Crohn's disease will be in remission or only have mild symptoms in the next 5 years. Around 45 percent of people in remission won't experience a relapse in the next year.

In any given year, 48 percent of those with ulcerative colitis are in remission, and 30 percent have mild symptoms. The longer someone remains in remission, the less likely they are to experience a flare in the following year.

Death due to IBD or its complications is uncommon. People with Crohn's disease have only a slightly higher overall mortality rate than the general population. Those with mild-to-moderate ulcerative colitis do not have a higher risk.

If people experience any persistent changes in bowel habits or any other symptoms of IBD, they should consult their doctor.