What is Crohn’s disease?

Crohn’s disease is a type of inflammatory bowel disease (IBD). If you have Crohn’s disease it means that you have inflammation of the lining of your digestive or gastrointestinal (GI) tract. This inflammation can affect any part of your GI tract, which includes your esophagus, stomach, the large intestine (also called the colon) and the small intestine.

The primary purpose of the GI tract is to move food through your system so that your body can absorb the fluids and nutrients it needs for healthy functioning before eliminating the waste. The inflammation that accompanies Crohn’s disease disrupts the healthy absorption of fluid and nutrients. Over time, this inflammation causes swelling of the intestinal passages. The swelling can slow the movement of food through the intestines resulting in pain, cramps and frequent emptying of the bowel.

What Causes Crohn’s Disease?

We don’t know for certain what causes the disease but researchers believe there is both a genetic and environmental link. Genetically, Crohn’s disease tends to run in families. Those with a first-degree relative with the disease are at higher risk for getting the disease. Researchers are still working to understand the exact genetic link.

There also appears to be an environmental component to the disease that creates an abnormal immune response. Typically, your immune system identifies harmful agents like unhealthy bacteria and viruses and destroys them. But, in Crohn’s disease, the immune system appears to attack beneficial bacteria causing an excess of white blood cells to accumulate in the lining of the intestines. This autoimmune response causes chronic inflammation of the intestines. Researchers believe that the autoimmune response might be triggered by environmental factors that are still under study.

Though certain foods and stress may worsen Crohn’s disease symptoms, neither are believed to be the cause of the disease.

Is There a Cure for Crohn’s Disease?

Because we haven’t clearly determined the cause of Crohn’s disease there is currently no cure. The basic goal of treatment is to decrease the inflammation of the GI tract, which then helps to control and manage the symptoms. Doctors typically use medications and nutrition to relieve symptoms and can even achieve a state of remission in some people. Sometimes surgery is also needed.

Though the disease is considered a chronic or life-long condition, proper treatment allows many to go long periods without symptoms or flare-ups. And it is possible to live a full and productive life with Crohn’s Disease.

Who Is Likely to Get Crohn’s Disease?

Crohn’s disease affects people of all ages though first symptoms usually begin between the ages of 13 and 30. Both men and women are affected by it and many have a biological relative with the disease. All ethnic groups are susceptible to the disease but Caucasians and those from Eastern European Jewish heritage are at greater risk, as are those who smoke.

Crohn’s Symptoms

Every person experiences Crohn’s disease differently. Some people have frequent occurrence of symptoms while others may have few, if any, symptoms. The symptoms of Crohn’s disease can range from mild to severe and may develop gradually or come on suddenly with no warning.

Most Common Symptoms Associated with Crohn’s Disease

  • Diarrhea. The more inflamed the intestinal wall becomes, the harder it is for the intestine to absorb water. The excess fluid that can’t be absorbed travels through the intestine and leads to a loose stool and diarrhea. The diarrhea may also contain blood. See Anemia and fatigue below.
  • Abdominal pain. The abdominal pain and cramping is caused by the swelling of the intestinal passageways making it difficult for food to move through the intestines. In mild cases of Crohn’s disease the abdominal discomfort ranges between slight and moderate. In more severe cases the cramping and discomfort may also cause nausea and vomiting.
  • Loss of appetite and weight loss. As a result of the cramping and abdominal pain, there is often a loss of appetite. Due to fewer meals and calories consumed, some people may experience weight loss. The inflammation of the intestines also makes it more difficult for your body to digest and absorb food.
  • Anemia and fatigue. Rectal bleeding may also occur. As food moves through your inflamed digestive track it may cause tissue to bleed. This blood loss may possibly lead to anemia, which is a condition where there are not enough red blood cells. Anemia causes fatigue.
  • Ulcers. Ulcers, which are small sores, can form on the surface of your intestines. Over time these eventually become larger and penetrate into the intestinal walls leading to more discomfort.
  • Fistulas. The inflammation that accompanies Crohn’s disease may also cause a fistula to develop. A fistula is an abnormal connection between an organ, vessel, or intestine and another structure. In Crohn’s disease, a fistula typically will develop as a tunnel from one loop of intestine to another and most commonly occurs around the anal area. This might cause drainage of mucus or stool from the anal opening.

Additional Symptoms of Crohn’s Disease May Include

  • Fever
  • Constipation
  • Swollen gums
  • Joint pain or swelling
  • Skin lumps or sores
  • Mouth or canker sores
  • Sores or drainage around the anus
  • Inflammation of the liver or bile duct
  • Eye inflammation or vision change in one or both eyes
  • Delayed growth or sexual development in children

Crohn’s Diagnosis

Diagnosing Crohn’s disease can be challenging. Since there is no single test that can make a definitive diagnosis of Crohn’s, your doctor will typically gather information from several sources. This process may begin with a physical exam and a health history and be followed up with lab tests and scans. Here are some of the most common ways doctors go about diagnosing Crohn’s disease.

Stool sample
The first lab test a doctor may perform might be to collect a stool sample to detect blood in the feces and find out if a protein called calproctectin might be present in the stool. Calprotectin is a major protein found in inflammatory cells and if detected in the sample, may indicate a need for further testing. Stools tests may also be ordered to look for signs of infection.

Blood test
A blood test may be ordered to see if you have anemia (a condition where there are not enough red blood cells) and to look for signs of infection and inflammation of the intestine.

This test enables your doctor to look inside your colon (large intestine) using a thin, flexible, lighted tube equipped with a tiny camera. A colonoscopy reveals any inflammation or ulcers in the intestine that might be caused by Crohn’s disease. During this procedure, small sample of tissue from the intestine might be taken (called a biopsy) and sent to the lab for analysis to help confirm the diagnosis.

Computerized tomography (CT) or Magnetic resonance imaging (MRI)
These tests allows your doctor to see the entire bowel (large and small intestines) and the tissues outside the bowel that can’t be seen with other tests. This helps your doctor better understand the location of the inflammation and check for possible complications such as partial blockages, abscesses or fistulas.

Capsule endoscopy
For this test you swallow a capsule that has a tiny camera in it. As the capsule moves through your digestive tract, the camera takes many pictures, which are transmitted to a computer that you wear on your belt. The images are then downloaded to a computer and assessed by your doctor. After the capsule has traveled the length of your digestive system it is easily and painlessly eliminated in your stool.

Small bowel imaging
This test looks specifically at the small bowel area to help locate areas of narrowing or inflammation that are common with Crohn’s disease. To perform the test you first must drink a solution containing barium. The barium coats the lining of the bowel making it visible on an X-ray or CT scan. Images are taken of the small bowel and analyzed by your doctor.

Treatment of Crohn’s Disease

Because there is not yet a cure for Crohn’s disease, the goals of treatment are to:
Reduce the inflammation in the affected areas of your digestive tract.
Prevent these flares and keep you in remission, whereby you are feeling well and have no symptoms.

Doctors typically use drug therapy to achieve relief of symptoms and control of inflammation. Depending on your unique situation, you may receive one or more of the drugs mentioned below. In the best cases, this drug therapy might also help facilitate long-term remission. In more severe cases, surgery may be needed. The type of treatment you will need depends on the location and severity of your inflammation.

Here are the most common drugs currently used to treat Crohn’s disease.

Mild Crohn’s Disease

Antidiarrheal medicines may slow or stop the painful intestinal spasm that cause symptoms. Some of these medicines, such as loperamide (Imodium), are available without a prescription while others, such as diphenoxylate (Lomotil) are available only by prescription. It is important to note that antidiarrheal medicines can be dangerous if you use them when you have moderate or severe inflammation of the colon. They can cause a serious complication called toxic megacolon where the colon swells to many times its normal size.

Probiotics as a treatment for IBD are promising. Unfortunately, probiotics appear to have little benefit in the treatment of Crohn’s disease specifically.

Advanced Crohn’s disease

These drugs are used to treat symptoms of Crohn’s disease that range from mild to moderate:

Anti-inflammatory drugs

  • Mesalazine or mesalamine (Asacol, Rowasa, Pentasa, Salofalk). This anti-inflammatory medication is designed to reduce inflammation. It has a long history of being used in patients with Crohn’s disease but over time clinical research has shown that it is only nominally effective in treating inflammation in the large intestine and not effective in treating inflammation in the small intestine. It can be taken orally or in the form of a enema or suppository.
  • Sulfasalazine (Azulfidine, Salazopyrin). This drug also reduces inflammation but has not shown promising results in treating Crohn’s disease, which can affect the entire gastrointestinal tract. It has shown to be somewhat effective when used for treating inflammation in the colon.

Antibiotic drugs

  • Metronidazole (Flagyl) and ciprofloxacin (Cipro). These drugs are can help reduce harmful intestinal bacteria and suppress the immune system. They can also reduce the amount of drainage and heal fistulas and abscesses that are common in Crohn’s disease.

Steroid drugs

  • Budesonide (Entocort) and prednisone. Budesonide is a steroid used to reduce inflammation . Entocort works faster than traditional steroids (such as prednisone) and appears to have fewer side effects. It has shown to be effective in treating inflammation in the lower small intestine and the first part of the large intestine, typically known as the is ileum. Prednisone is also a steroid but attacks inflammation throughout the body and acts as an immune suppressant. Those taking prednisone typically only stay on it for is several weeks because it is known to have unpleasant side effects.

Immune system suppressor drugs

  • Azathioprine (Imuran) and mercaptopurine (Purinethol). These are two of the most widely used immune system suppressants. Immune suppressants reduce inflammation by making the immune system less active. Though a less robust immune system helps with inflammation, it also puts you at higher risk for infection, so use of these drugs need to be closely monitored by your doctor.
    Methotrexate (Rheumatrex). This drug, which is most often used to treat cancer, psoriasis and rheumatoid arthritis, is sometimes used for those with Crohn’s disease who don’t respond well to other medications.

Biologic drugs

Cannabis is receiving a lot of interest as a treatment for Crohn’s disease. There are no easy answers to questions about how effective it is and how safe it is. But emerging results are intriguing, to say the least.

It’s important to note that common immunosuppressants used to treat Crohn’s disease, such as prednisone and biologics, may put patients in a higher risk group for COVID-19.

Nutrition therapy

In some cases, your doctor may recommend a special type of nutrition therapy that supplies you with the needed nutrients but allows your bowel and digestive system to rest. This type of nutrition is given through a feeding tube inserted through the nose directly into the digestive tract (called enterel nutrition) or it can also be injected into a vein (parenteral nutrition). Giving your bowel a rest can help reduce inflammation. This type of nutrition therapy is often used to help prepare for surgery or control symptoms that aren’t responding to medications.

Surgery for Crohn’s disease

Surgery is most commonly recommended when Crohn’s disease has resulted in an infection, an abscess, when there is a bowel obstruction, when abnormal connections to other organs (fistulae) develop or when the patient is experiencing malnutrition from an inability to properly absorb nutrients.

There are five types of surgical procedures used to treat Crohn’s disease. The type used will depend on the specific complication, the location in the gastrointestinal tract and the severity of the symptoms. These surgical approaches include:

  1. Resection. This surgical procedure removes a part of the intestine and is the most commonly performed procedure. After one or more select sections of the intestine are removed, which are usually identified through pre-operative investigations, the remaining healthy sections are put back together.
  2. Colectomy. If Crohn’s disease affects a significant portion of the colon (large intestine) a colectomy, a partial or complete removal of the colon, may be necessary. If the colon is totally removed, the end of the small intestine can be attached to the rectum.
  3. Proctocolectomy. If both the colon and rectum are diseased, it may be necessary to remove both in a procedure called a proctocolectomy. The surgery can involve bringing the ends of the small intestine through an incision in the lower abdomen (called a stoma) so that waste can empty from the body into an external bag (pouch).
  4. Strictureplasty. In situations where multiple segments of intestine are inflamed or damaged by Crohn’s disease, a special procedure called a strictureplasty can be performed to widen portions of the intestine that have narrowed (or become constricted) due to the buildup of scar tissue over time.
  5. Fistulotomy. This procedure may be necessary if fistulas are present. Fistulas are tunnels that are created when an ulcer tunnels through the intestine and into the surrounding tissue. In a typical fistulotomy, the surgeon cuts the fistula tract, and scrapes out the infected tissue.

Crohn’s Disease Diet

Although there is no substantial evidence that diet alone can treat or cure Crohn’s disease, clinical practice and scientific evidence show that proper nutrition and specific dietary changes may help manage many challenges that come along with the disease. Amongst these challenges are dietary issues associated with Crohn’s disease, including: energy and nutrient deficiencies, weight loss, fatigue, and individual food intolerances that may worsen symptoms. In order to address these major issues, dietary management of Crohn’s disease should be focused on two major areas – meeting energy and nutrient needs, and symptom management.

The dietary strategies that may be used together with drug therapy for symptom management of IBD are to avoid or limit foods that trigger symptoms, and to increase foods of benefit to overall health. Dietary intake may change quite a bit when experiencing a flare compared to remission. During a flare, individuals with Crohn’s disease often find relief by consuming a low-fiber diet. Whereas when in remission, it is recommended that high-fiber foods are gradually added back in for optimal health. Certain foods that may not cause symptoms during remission may trigger them during a flare. These may include:

  • Carbonated, or “fizzy,” drinks
  • High-fiber foods such as popcorn, vegetable skins, and nuts
  • Fatty foods

One of the challenges with Crohn’s disease is that there is not one particular diet that works for everyone with the disease. Foods that worsen symptoms for one individual may be very different than foods that worsen symptoms for the next. It is important that each individual with Crohn’s disease find his/her own specific food intolerances.

Two of the more successful elimination diets that exist to date for individuals are:

  1. The Specific Carbohydrate Diet (SCD). The goal of the diet is to “starve out” harmful bacteria and restore the balance of bacteria in the gut. The diet proposes that complex carbohydrates are not easily digested and therefore feed harmful bacteria in our digestive tract causing them to overgrow producing by-products and inflaming intestine wall.
  2. The Low FODMAP diet. This diet eliminates foods that are high in short-chain carbohydrates in order to decrease symptoms. This diet was developed by gastroenterologist Dr. Peter Gibson and registered dietitian Dr. Sue Shepherd to decrease functional gut symptoms such as gas, bloating, distention and diarrhea and/or constipation.

Types of Crohn’s disease

Though Crohn’s is typically discussed as if it is one disease, there are different types of Crohn’s disease. One could classify it by the location of the inflammation within the digestive tract:

  • Ileocolitis. This is the most common type of Crohn’s disease, accounting for about half of all cases. It affects the lower portion of the small intestine (known as the terminal ileum) and the colon. People who have ileocolitis may experience considerable weight loss, diarrhea, and cramping or pain in the middle or lower right part of the abdomen.
  • Ileitis. This type of Crohn’s disease also affects the ileum. It accounts for about a third of cases. Symptoms are the same as those for ileocolitis.
  • Crohn’s colitis. This type of Crohn’s affects only the colon (large intestine) and accounts for about 20% of cases. Symptoms may include skin lesions, joint pains, diarrhea, rectal bleeding, and the formation of ulcers, fistulas, and abscesses around the anus.
  • Gastroduodenal Crohn’s. This type affects the stomach and duodenum (the first portion of the small intestine). People with this type of Crohn’s disease suffer nausea, weight loss and loss of appetite. In addition, if the narrow segments of bowel are obstructed, the person may experience vomiting.
  • Jejunoileitis. This form of the disease causes areas of inflammation in the jejunum, which is the upper half of the small intestine. Symptoms include cramps after meals, diarrhea, and abdominal pain that can become intense.

In addition to classifying it by the location within the digestive tract, Crohn’s can also be categorized by the different ways it behaves as it progresses. There are three categories that describe the different ways that Crohn’s presents.

  1. Inflammatory behavior. This progression can cause inflammation anywhere in the gastrointestinal tract (which includes your mouth, esophagus, stomach, large intestine and small intestine). Symptoms may range from mild to severe. This inflammation will cause periods in which the disease flares up (is active) and causes symptoms. In between flares, you may experience no symptoms (called remission) that can span months or even years.
  2. Stricturing behavior. This progression of Crohn’s causes narrowing of the intestine that can lead to bowel obstruction (a blockage that keeps food or liquid from passing through your intestines).
  3. Penetrating behavior. The final type of progression creates abnormal passageways (called fistulas) between the intestine and bladder, vagina or skin. Approximately 20-40% of people develop fistulas at some point.

Risk Factors

Patients may have a more severe disease course of Crohn’s disease defined by complications, need for surgery, hospitalizations, chronic active symptoms. Risk factors include:

  • Being diagnosed with Crohn’s disease at an early age. Crohn’s disease diagnosed under age 40 has been associated with a more severe disease course, such as need for corticosteroids and disease flares. Approximately 25% of newly diagnosed cases occur in those under the age of 20 and early onset can be predictive of a more severe course. Pediatric Crohn’s may develop due to a genetic factor. About 30% of children with Crohn’s disease have a close family member who also has the disease. In addition to gastrointestinal symptoms that the disease can cause, some children with Crohn’s experience delayed puberty and some fail to grow at a normal rate. About one-third of children with Crohn’s disease do not reach their final adult height because of the disease.
  • Smoking. Smoking appears to increase the risk of developing Crohn’s disease. It is also associated with more severe disease and an early need for surgery. Those with Crohn’s who also smoke may experience more frequent flares, such as abdominal pain and diarrhea, are more likely to require surgery than non-smokers with Crohn’s, and are more likely to have Crohn’s disease come back after surgery.
  • The presence of perianal or stricturing disease.
    • Perianal disease is inflammation at or near the anus. Inflammation around the anal area can cause fistulas (abnormal passages or tunnels between an organ and the body surface), abscesses (pockets of infection), skin tags, anal fissures (tears or splits in the anal canal).
    • Stricturing disease occurs from inflammation in the intestine that creates scar tissue that narrows the passage (called a stricture) of the intestine, causing bowel obstruction, severe cramps and vomiting. Strictures usually occur in the small intestine but can also occur in the large intestine.
  • Steroid use early in the course of treatment. Early use of corticosteroids (commonly called steroids) in treatment is also a predictor of poor outcome. Corticosteroids are powerful anti-inflammatory drugs used for treating Crohn’s disease in adults. Because they carry significant side effects, steroids are typically reserved for those with moderate-to-severe disease or those who relapse after other therapies. They can be very effective short term therapies, but avoiding long or repeated treatments with corticosteroid is an important goal in treating Crohn’s disease. Other medications can help reduce the need for corticosteroids.
  • Surgery needed within the first year of treatment. The presence of deep ulcers, severe upper gastro-intestinal lesions (Crohn’s involving the stomach or esophagus, for example) or extensive small bowel disease may increase the risk of requiring surgery shortly following diagnosis.

What Is the Difference Between Crohn’s Disease and Other Inflammatory Bowel Diseases (IBDs)?

Crohn’s disease is often assumed to be the same condition as ulcerative colitis, both of which are considered to be inflammatory bowel diseases (IBDs). Though there is some overlap in symptoms between Crohn’s disease and ulcerative colitis, different parts of the body are affected. Crohn’s disease can affect any part of the GI tract, from the mouth to the anus, while ulcerative colitis is limited to the colon.

The inflammation that accompanies Crohn’s disease can affect the entire thickness of the bowel wall. In contrast, only the innermost lining of the colon is affected with ulcerative colitis.

Another difference is that in Crohn’s disease, the inflammation of the intestine can be intermittent with spaces of normal, non-inflamed areas between the affected areas. In ulcerative colitis this spacing of inflammation does not occur.

In only about 10% of cases a person will have symptoms of both Crohn’s disease and ulcerative colitis.


Most women with Crohn’s disease can have a normal pregnancy and a healthy baby. The majority of medications used to treat Crohn’s disease or ulcerative colitis are safe for pregnancy. Because having a flare is associated with potentially serious problems for both the mother and fetus, most doctors feel this it the worst time to ‘take a chance’ by stopping Crohn’s or colitis medications.