What Is Crohn's Disease? Symptoms, Causes, and Treatments

What is Crohn's Disease?

Overview of Inflammatory Bowel Disease

Crohn’s disease is a chronic inflammatory condition that can affect any part of the digestive tract, but it commonly develops in the small intestine and the upper part of the large intestine. It is an inflammatory bowel disease (IBD) that develops due to an exaggerated immune response. Inflammatory bowel diseases such as Crohn’s disease and ulcerative colitis cause inflammation (swelling and irritation) in the gastrointestinal tract.

The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) estimates that approximately 750,000 Americans are living with Crohn’s disease.

People with Crohn’s disease experience symptoms such as fatigue, abdominal pain, chronic/severe diarrhea, nausea, vomiting, and appetite loss, leading to malnutrition and weight loss. There is no cure for the condition, but medications are available to manage Crohn’s disease and prevent complications.

What Does Crohn's Disease Do to the Digestive Tract

Crohn’s disease causes inflammation in the digestive tract, mainly in the small intestine and the upper part of the large intestine. There are 5 types of Crohn’s disease, based on the affected section of the digestive tract:

Gastroduodenal: inflammation of the stomach and upper part of the small intestine called the duodenum.
Jejunitis: inflammation in the upper part of the small intestine called the jejunum.
Ileitis: inflammation in the lining of the small intestine or ileum.
Ileocolitis: inflammation in the lower part of the small intestine and the first part of the large intestine or colon. This is the most common type of Crohn’s disease.
Colitis: inflammation of only the colon or large intestine.

Complications of Crohn’s disease include:

Perianal disease: inflammation, fistulas, and abscesses in the anal area.
Ulcers: these open sores are caused by inflammation, growing outward through the intestine wall.
Growth delay can happen in children with Crohn’s disease

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Symptoms of Crohn's Disease

Common Symptoms

Crohn's disease symptoms range from mild to severe. IBD symptoms typically develop gradually but can occur without warning. The symptoms can go through periods of increased activity and remission. Common symptoms of Crohn’s disease include:

Severe/chronic diarrhea (can be watery or loose)
Abdominal pain
Stomach cramps
Blood in stool or rectal bleeding
Fatigue and feeling generally unwell
Fever
Mouth ulcers
Loss of appetite
Weight loss
Anal fistula symptoms (pain, drainage)

Other Symptoms of Severe Crohn’s Disease

In people with more severe disease, Crohn’s disease can affect other parts of the body outside the digestive tract, such as:

Inflammation in the skin and skin lesions (erythema nodosum, pyoderma gangrenosum), eye inflammation (uveitis, episcleritis), and joint inflammation (peripheral arthritis, axial arthritis, ankylosing spondylitis).
Other gastrointestinal and liver diseases (gallstones, primary sclerosing cholangitis), hepatitis, and fatty liver disease.
Nephrolithiasis (kidney stones), fistulas, amyloidosis (abnormal protein deposits in organ tissues such as the kidneys.
Mineral and vitamin deficiencies, such as iron deficiency anemia.
Osteoporosis, osteopenia since 30% to 60% of IBD patients have lower-than-average bone density due to malnutrition
Delayed growth or sexual development in children.

Complications of Crohn’s Disease: How Serious is Crohn's?

Untreated Crohn's disease can lead to serious complications such as:

Bowel obstruction (blockage in the gastrointestinal tract).
Ulcers (sores) anywhere along the length of the GI tract.
Fistulas (abnormal connections) between different body parts, such as the GI tract and the skin of the anal area (perianal fistula).
Fissures (small tears in the lining of the anus and surrounding tissues).
Infections and abscesses (pus-filled fluid collections).
Malnutrition due to diarrhea and loss of appetite.
Health problems such as anemia, osteoporosis, arthritis, and liver or gallbladder disease.
Increased risk of colon cancer.
Increased risk of blood clots.
Hidradenitis suppurativa, a skin disorder associated with deep nodules and abscesses in the armpits, under the breasts, in the groin, and in the perianal and genital areas.
Increased risk of infections due to the effects of Crohn’s drugs on immune function.
Increased risk of certain cancers like skin cancers and lymphoma due to the effects of Crohn's disease medications on the body’s immune system.
Higher risk of mental health conditions such as anxiety and depression.

Causes: What Are the Triggers for Crohn's Disease?

Immune System

The exact cause is unknown, but research suggests that bacterial or viral infections might trigger Crohn's disease, although no specific triggers have been found. The theory is that when the immune system is activated to fight off certain microorganisms, an abnormal immune response occurs, causing the immune system to mistakenly attack healthy cells in the digestive tract as well.

Genetic Factors

Many people with Crohn's disease do not have family members with the condition. However, there may be a genetic component because 1 in 5 people with a family history of the condition develop Crohn’s disease.

Environmental Factors and Other Risk Factors

Age: Crohn's affects mainly young people in their 20s and 30s. However, people of any age can develop Crohn’s disease.
Ethnicity: Caucasians are at the highest risk of developing Crohn’s disease, especially Ashkenazi Jews of Eastern European descent. But more Black people in the US and UK are being diagnosed with Crohn's disease now, as are people in the Middle East.
Family History: People who have first-degree relatives (parent, sibling, child) with Crohn’s disease are at a higher risk of having it themselves.
Smoking: Cigarette smoking is associated with more severe Crohn’s disease and the need for surgical interventions.
Medications: Nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen (Motrin, Advil), naproxen (Naprosyn, Aleve), diclofenac, and others do not cause Crohn's disease, but can cause inflammation in the gastrointestinal tract and worsen Crohn's disease.

How is Crohn’s Disease Diagnosed?

There is no single test that can give a confirmed diagnosis of Crohn’s disease. Healthcare professionals diagnose Crohn's disease based on symptoms, bowel habits, medical history, physical exam, and diagnostic testing, which may include:

Blood tests, for example, a blood test to look for inflammatory markers or signs of anemia.
Stool tests, such as stool culture or fecal calprotectin, to look for signs of infection-causing microorganisms or inflammatory markers in stool (poop).
Sigmoidoscopy or colonoscopy to view the lining of your colon (large intestine) and terminal ileum (lower part of the small intestine). This test is done by inserting a thin tube with a light and camera attached at its tip. Your doctor can also take a small tissue sample (biopsy) for examination in the laboratory. The presence of inflammatory cell clusters called granulomas is suggestive of a diagnosis of Crohn's.
Imaging tests such as computerized tomography (CT), which are special X-rays, to look at your bowel and surrounding tissues. CT enterography is done using a contrast agent for more detailed images of the small intestine. Pelvic magnetic resonance imaging (MRI) or MR enterography may be done to evaluate an anal fistula or the small intestine.
Capsule endoscopy is a test in which you swallow a small capsule-like divide that contains a camera. It takes pictures of your small intestine and transmits them to a wearable recorder. These images can help your healthcare providers look for signs of Crohn's disease in your digestive system. The capsule is painlessly eliminated in the stool.
Endoscopy, a minimally invasive procedure, that allows your doctors to look at your small bowel. This may be necessary for a Crohn's disease diagnosis if you are not a candidate for capsule endoscopy due to a suspected stricture (narrowing) or obstruction (blockage) in your bowel.
Balloon-assisted enteroscopy, a test that allows your doctors to look at parts of the small intestine that a routine endoscopy does not examine. It may be done if capsule endoscopy shows suspicious areas but the diagnosis remains unclear.

Treatment Options for Crohn's Disease

Medications for Crohn’s Disease

Some of the prescription medications a gastroenterologist might prescribe to manage Crohn’s disease or treat complications of Crohn’s disease include:

Anti-inflammatory drugs, such as corticosteroids (budesonide) to reduce inflammation and achieve short-term improvement in IBD symptoms.
Immunomodulator drugs, such as azathioprine (Imuran, Azasan), mercaptopurine (Purixan, Purinethol), and methotrexate (Trexall) for reducing immune system activity and chronic inflammation.
Biologic agents, such as vedolizumab (Entyvio), infliximab (Remicade), adalimumab (Humira), certolizumab pegol (Cimzia), ustekinumab (Stelara), and risankizumab-rzaa (Skyrizi). These drugs interfere with the immune and inflammatory responses that cause IBD symptoms.
Antibiotics, such as ciprofloxacin (Cipro) and metronidazole (Flagyl), to treat severe infections and draining fistulas and abscesses.
Other medications to relieve symptoms, such as:
- Anti-diarrhea medicines such as loperamide (Imodium A-D).
- Fiber supplements like psyllium (Metamucil) or methylcellulose (Citrucel).
- Pain relievers such as acetaminophen (Tylenol) to manage the symptoms of Crohn’s disease. Note: Common pain relievers called NSAIDs (ibuprofen, naproxen) are not suitable for Crohn’s patients as they can cause worsening symptoms.
- Nutritional supplements to treat deficiencies.

Surgery

If dietary modifications, lifestyle changes, and medications do not control Crohn’s disease, surgery may be necessary to remove the damaged portion of the gastrointestinal tract or to treat complications. Nearly 50% of people with Crohn's disease require surgery at least once during their lifetime. While surgery can provide symptom relief, it is not a cure for Crohn's disease.

Diet Changes

People living with Crohn’s disease may need to eat a special diet by mouth, through a feeding tube, or through intravenous infusion of nutrients. This not only gives the body important nutrients but also allows the bowel to take a break. Doctors have found that a bowel rest often leads to a short-term reduction in inflammation.

If you have a stricture (narrowing in your bowel), your healthcare provider may recommend eating a low-fiber diet (high-fiber foods can increase the risk of intestinal blockage).

Living with Crohn's Disease

Lifestyle changes can help in managing Crohn’s disease symptoms and going longer between flare-ups.

Dietary Modifications

There is no specific diet for Crohn’s disease, but keeping a food diary can help you identify foods and beverages that can trigger inflammation and worsen symptoms of inflammatory bowel disease. Some of the things people with Crohn’s disease find helpful in terms of dietary modifications include:

Limiting intake of dairy products and using enzyme products like Lactacid.
Eating smaller, more frequent meals, rather than 2-3 large meals.
Staying well hydrated with water.
Avoiding alcohol and caffeinated beverages.
Taking multivitamins and other dietary supplements.
Working with a licensed nutritionist or dietitian to identify healthy eating plans.

Smoking Cessation

Smoking tobacco is linked to an increased risk of developing Crohn's disease and worsening symptoms in people who already have inflammatory bowel disease. If you smoke, talk to your healthcare provider about smoking cessation aids that can help you quit smoking.

Stress Management

There is no evidence that stress causes Crohn's disease, but it can make the symptoms worse. Getting regular physical exercise; practicing mind-body relaxation techniques like deep breathing, body scan meditation, progressive muscle relaxation, yoga, and tai-chi; and engaging in stress-reduction techniques like biofeedback can help to control Crohn’s symptoms and flare-ups.

Support, Resources, and Further Reading

Crohn’s and Colitis Foundation (CCF)
American Gastroenterological Association
Living Well with Inflammatory Bowel Disease: A Self-Management Handbook

Common Questions and Concerns

Does Crohn's Ever Go Away?

Crohn’s disease does not ever really go away. However, treatments can help to control the symptoms. However, Crohn’s disease often comes back. Currently, there is no cure for Crohn's disease or single treatment that works for everyone. Your healthcare team will develop a treatment plan for Crohn’s based on the severity of your IBD symptoms. You may need to try different medications and treatments to find the ones that work for you to reduce symptoms and achieve long-term remission.

What is the Life Expectancy of a Person with Crohn's Disease?

Most people with Crohn's disease have a normal life expectancy. The condition is not life-threatening or fatal, but it can affect quality of life. Managing Crohn’s disease by implementing dietary restrictions and stress-reducing activities can help to prevent potentially serious complications that could affect life expectancy.