What I need to know about 

Crohn’s Disease 

NATIONAL INSTITUTES OF HEALTH 

U.S. Department 

of Health and 

Human Services National Digestive Diseases 

Information Clearinghouse

 

What I need to know about 

Crohn’s Disease 

U.S. Department 

of Health and

Human Services

NATIONAL INSTITUTES OF HEALTH 

National Digestive Diseases 

Information Clearinghouse

Contents

What is Crohn’s disease?........................................ 1

Who gets Crohn’s disease?..................................... 3

What causes Crohn’s disease? ............................... 3

What are the symptoms of Crohn’s disease?........ 4

How is Crohn’s disease diagnosed?....................... 5

What are the problems of Crohn’s disease? ....... 10

How is Crohn’s disease treated?.......................... 12

Can smoking make Crohn’s disease worse? ....... 18

Can stress make Crohn’s disease worse? ............ 18

Is pregnancy safe for women with 

Crohn’s disease?.................................................... 19

Points to Remember ............................................. 19

Hope through Research ....................................... 21

Pronunciation Guide............................................. 22

For More Information .......................................... 23

Acknowledgments ................................................. 24

 

 

 

 

 

 

 

What is Crohn’s disease? 

Crohn’s disease is a disease that causes 

inflammation, or swelling, and irritation of 

any part of the digestive tract—also called 

the gastrointestinal (GI) tract. The part most 

commonly affected is the end part of the small 

intestine, called the ileum. 

Normal 

Inflamed 

In Crohn’s disease, parts of the GI tract become inflamed 

and scarred. 

*See page 22 for tips on how to say the words in 

bold type. 

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Crohn’s disease is one of two main forms of 

diseases of the GI tract named inflammatory bowel 

disease (IBD). The other form, called ulcerative 

colitis, affects the large intestine, which includes 

the colon and the rectum—the lower end of the 

large intestine, leading to the anus. 

With Crohn’s disease, chronic—or long lasting— 

inflammation may cause scar tissue to form in the 

lining of the intestine. When scar tissue builds up, 

the passage can become narrow, causing food and 

stool to move through the GI tract more slowly— 

which can lead to pain, cramps, and diarrhea. 

Normal digestive tract Swollen digestive tract 

When scar tissue builds up, the passage can become 

narrow. 

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Who gets Crohn’s disease? 

Both men and women can get Crohn’s disease, 

and it can run in families. People with Crohn’s 

disease may have a blood relative with the disease 

or another type of IBD. Crohn’s disease most 

commonly starts between the ages of 13 and 30. 

What causes Crohn’s disease? 

Researchers are studying the possible causes of 

Crohn’s disease. Your body’s natural defense 

system, called the immune system, protects 

you from infection by fighting against bacteria, 

viruses, and other things that can make you sick. 

Researchers believe that with Crohn’s disease, 

the immune system attacks harmless bacteria and 

viruses. During the attack, white blood cells gather 

in the intestinal lining. The white blood cells cause 

chronic inflammation, which leads to ulcers, or 

sores, and damage to the intestines. 

Other factors associated with Crohn’s disease are 

● genes—the traits passed down from your parents 

● unknown triggers caused by the environment 

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What are the symptoms of Crohn’s 

disease?

Crohn’s disease symptoms can be different for each 

person. The most common symptoms of Crohn’s 

disease are 

●	 abdominal pain—often in the lower right area of 

the abdomen 

●	 diarrhea 

●	 bleeding in the rectum, which can be seen in a 

person’s underwear, in the toilet, or in a bowel 

movement; rectal bleeding can be serious and 

may not stop without medical help 

●	 weight loss 

●	 fever 

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How is Crohn’s disease diagnosed? 

A doctor will perform a physical exam and tests to 

diagnose Crohn’s disease. During your visit, the 

doctor will ask about your symptoms and medical 

history. 

The doctor may order blood tests, which involve 

drawing blood at a health care provider’s office or 

commercial facility and sending the sample to a lab 

for analysis. Blood tests can show anemia caused 

by bleeding. Anemia is a condition in which red 

blood cells are fewer or smaller than normal, which 

means less oxygen is carried to the body’s cells. 

Blood tests can also show a high white blood cell 

count, a sign of chronic inflammation. 

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You may also be asked for a stool sample. A stool 

test is commonly used to rule out other causes of 

GI diseases, such as infections. The doctor will 

give you a container for catching and storing the 

stool. The sample is returned to the doctor or a 

commercial facility and sent to a lab for analysis. A 

stool sample can also be used to check if you have 

bleeding or inflammation. 

Other tests may be needed to diagnose Crohn’s 

disease. The following tests are all performed at a 

hospital or outpatient center. 

●	 Colonoscopy. Colonoscopy is the most 

commonly used test to specifically diagnose 

Crohn’s disease. This test is used to look inside 

your rectum, entire colon, and ileum. The 

health care provider will give you written bowel 

prep instructions to follow at home before the 

test. You may need to follow a clear liquid diet 

for 1 to 3 days before the test. You will need to 

take laxatives and enemas the evening before the 

test, and you will likely have one or more enemas 

about 2 hours before the test. A laxative is 

medicine that loosens stool and increases bowel 

movements. An enema involves flushing water, 

laxative, or sometimes a mild soap solution into 

the anus using a special squirt bottle. 

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For the test, you will lie on a table while the 

doctor inserts a flexible tube into your anus. A 

small camera on the tube sends a video image of 

the intestinal lining to a computer screen. The 

doctor can see inflammation, ulcers, or bleeding. 

The doctor may also perform a biopsy. The 

doctor will look at the tissue with a microscope 

to confirm the diagnosis of Crohn’s disease. In 

most cases, you’ll be given a light sedative, and 

possibly pain medicine, to help you relax. You 

will not feel the biopsy. 

Cramping or bloating may occur during the first 

hour after the test. Driving is not permitted 

for 24 hours after the test to allow the sedative 

time to wear off. Before the appointment, you 

should make plans for a ride home. By the next 

day, you should fully recover and go back to your 

normal diet. 

●	 Flexible sigmoidoscopy. This test is used to look 

inside the rectum and lower colon. The health 

care provider will give you written bowel prep 

instructions to follow at home before the test. 

You may need to follow a clear liquid diet for 

1 to 3 days before the test. You may also need a 

laxative or enema the night before the test. And 

you’ll have one or more enemas about 2 hours 

before the procedure. 

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For the test, you will lie on a table while the 

doctor inserts a flexible tube into your anus. You 

will not need a sedative for the test. A small 

camera on the tube sends a video image of the 

intestinal lining to a computer screen. The doctor 

can see inflammation, ulcers, or bleeding. The 

doctor may also perform a biopsy by snipping 

a bit of tissue from the intestinal lining. The 

doctor will look at the tissue with a microscope to 

confirm the diagnosis of Crohn’s disease. You will 

not feel the biopsy. 

You can usually go back to your normal diet 

after the test, though you may have cramping or 

bloating during the first hour after the test. 

●	 Computerized tomography (CT) scan. A CT scan 

uses x rays and computers to create images of the 

inside of the body. For the test, you will lie on a 

table that slides into a tunnel-shaped device where 

the x rays are taken. The technician may give you 

a solution to drink and an injection of a special 

dye through a needle inserted into an arm vein. 

You will not need a sedative for the test. CT scans 

can be used to help diagnose Crohn’s disease. 

●	 Upper GI series (x rays). An upper GI series may 

be done to look at the small intestine. No eating 

or drinking is allowed for 8 hours before the 

procedure. You will not need a sedative for the 

test. During the procedure, you will stand or sit 

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in front of an x-ray machine and drink barium, 

a chalky liquid. The barium coats the small 

intestine, making signs of the disease show up 

more clearly on x rays. 

After the test, you may go back to your normal 

diet, though you may have nausea or bloating for 

a short time. Traces of barium in the GI tract 

cause stools to be white or light colored for a few 

days after the test. 

●	 Lower GI series (x rays). A lower GI series 

may be done to look at the large intestine. The 

health care provider will give you written bowel 

prep instructions to follow at home before the 

test. You will be asked to follow a clear liquid 

diet for 1 to 3 days before the test. A laxative or 

enema is usually used the evening before a lower 

GI series. Enemas are sometimes repeated the 

morning of the test. 

For the test, you will lie on a table while the 

doctor inserts a flexible tube into your anus. 

You will not need a sedative for the test. The 

large intestine is filled with barium, making signs 

of the disease show up more clearly on x rays. 

After the test, you may go back to your normal 

diet, though you may have bloating. You also 

may have some soreness of the anus. Traces of 

barium in the GI tract cause stools to be white or 

light colored for a few days after the test. 

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What are the problems of Crohn’s 

disease?

Intestinal blockage can occur in people with 

Crohn’s disease when scar tissue blocks the 

intestinal passage. A narrow intestinal passage 

is called a stricture. When the passage blocks 

completely, food and stool stop moving, causing 

abdominal cramps and vomiting. If you have these 

symptoms, you should see a health care provider 

right away. 

Ulcers from Crohn’s disease can cause tunnels 

to form through the inflamed areas, or even the 

healthy parts, of the intestine. These tunnels are 

called fistulas. Fistulas are seen most often in the 

areas around the rectum and anus. Sometimes a 

pocket of infection, called an abscess, can form 

in and around the fistulas. Most fistulas can be 

treated with medicines, but sometimes surgery is 

needed. 

People with Crohn’s disease often have anemia, 

which can be caused by the disease itself or by iron 

deficiency. Anemia may make a person feel tired. 

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People with Crohn’s disease, particularly if they 

have been treated with steroid medicines, may have 

weakness of their bones—called osteoporosis or 

osteomalacia. 

People with Crohn’s disease may also have 

arthritis, skin problems, swelling in the eyes 

or mouth, kidney stones, gallstones, and liver 

problems. Some people with Crohn’s disease 

may have restless legs syndrome—extreme 

leg discomfort the person feels while sitting 

or lying down. These problems may go away 

during treatment, but some must be treated with 

medicines. 

People who have Crohn’s disease may not get 

enough nutrition, such as protein, vitamins, or 

calories, because they 

●	 have an upset stomach that keeps them from 

eating enough calories 

●	 may not be able to absorb nutrients in the 

intestine 

Children with Crohn’s disease may fail to grow 

normally and may have low height for their age. 

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How is Crohn’s disease treated? 

Treatment for Crohn’s disease depends on 

● where the disease is located in the GI tract 

● what problems you already have from the 

disease 

●	 what past treatments you have had for the 

disease 

The goals of treatment are to 

●	 decrease the inflammation 

●	 relieve symptoms such as abdominal pain, 

diarrhea, and rectal bleeding 

● correct nutritional problems 

Treatment may include 

●	 medicines 

●	 surgery 

●	 eating, diet, and nutrition 

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Medicines 

One or more of the following medicines may be 

used to treat Crohn’s disease: 

●	 Anti-inflammation medicines may be used first 

to treat your Crohn’s disease. These medicines 

help lower inflammation in the intestine and 

relieve the pain and diarrhea. Sometimes antiinflammation medicines cause side effects, so 

you should talk with your health care provider 

about what to expect. 

●	 Steroids also help lower inflammation. Steroids 

are similar to natural chemicals in the body. 

However, steroids are used only for a short time 

because long-term use can lead to serious side 

effects. 

●	 Immune system suppressors. Azathioprine 

and 6-mercaptopurine work by keeping your 

immune system from attacking harmless foreign 

substances. Immune system suppressors also 

cause side effects, so you should talk with your 

health care provider about what to expect. 

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●	 Biological therapies. Biological therapies are 

medicines that are given by an injection in the 

vein, infliximab (Remicade), or an injection 

in the skin, adalimumab (HUMIRA). Your 

health care provider may treat you with these 

medicines if others are not helping to decrease 

inflammation, or if you have fistulas with 

abscesses. The goals for using these medicines 

are to get you better, keep you better, and avoid 

long-term steroid use. 

●	 Antibiotics. Antibiotics are used to treat 

bacterial overgrowth in the small intestine 

caused by stricture, fistulas, or surgery. For this 

common problem, the doctor may prescribe one 

or more of the following antibiotics: ampicillin, 

sulfonamide, cephalosporin, tetracycline, or 

metronidazole. 

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●	 Anti-diarrheal medicines and fluid replacements. 

Diarrhea and abdominal cramps are often 

relieved when the inflammation improves, but 

more medicine may be needed. Anti-diarrheal 

medicines include diphenoxylate, loperamide, 

and codeine. People with diarrhea should drink 

plenty of fluids to prevent dehydration—loss 

of fluids from the body. If diarrhea does not 

improve, the person should see the doctor 

promptly for possible treatment with fluids given 

through a small tube inserted into an arm vein. 

Surgery 

Some people with Crohn’s disease need surgery 

if medicines are no longer working to control 

blockage, fistulas, abscesses, and bleeding. A 

surgeon performs the procedure in a hospital, 

where you will receive medicine to make you sleep 

during the surgery. 

One or more of the following surgeries may be 

needed: 

●	 Intestinal resection. The surgeon removes the 

diseased section of intestine and puts the ends of 

the intestine back together. 

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●	 Proctocolectomy. Proctocolectomy is surgery 

to remove the rectum and part or all of the 

colon. An ileostomy is performed with a 

proctocolectomy. 

●	 Ileostomy. Ileostomy is an operation to create 

an opening—called a stoma—for the stool to exit 

the body when the ends of the intestine cannot 

be put back together. To create a stoma, an end 

of the intestine is brought out through a small 

opening made on the lower right part of the 

abdomen near the beltline. The stoma is about 

the size of a quarter. An ostomy pouch is worn 

outside the body over the stoma to collect waste, 

and it is emptied several times a day. Your 

health care provider may refer you to an ostomy 

nurse—a specialist who cares for people with an 

ostomy pouch. 

Surgery usually does not cure Crohn’s disease 

forever. Sometimes you need to have more than 

one surgery because the disease returns next to 

where the intestine was removed. Because Crohn’s 

disease can return after surgery, you can talk with 

your health care provider and other patients to 

get as much information as possible before having 

surgery. 

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Eating, Diet, and Nutrition 

Your health care provider may start you on a 

special diet, so you get extra nutrition and calories. 

High-calorie liquid supplements are often used 

to give you the extra calories and right amount of 

vitamins and minerals to keep you healthy. During 

acute phases of the disease, you may need to 

receive intravenous nutrition to give the intestine a 

rest. 

No foods are known to cause injury or 

inflammation to the intestine. But foods such as 

hot spices, alcohol, greasy foods, and milk products 

may make diarrhea and cramping worse. You 

should eat a healthy diet and avoid foods that 

make symptoms worse. Your health care provider 

may refer you to a dietitian to help you with meal 

planning. 

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Can smoking make Crohn’s disease 

worse?

People with Crohn’s disease who smoke may have 

worse symptoms and more problems from the 

disease. If you smoke, you’re more likely to need 

surgery than a person with Crohn’s disease who 

does not smoke. Quitting smoking can help make 

your Crohn’s disease less severe. Ask your health 

care provider if you need help quitting smoking. 

Can stress make Crohn’s disease 

worse?

People with Crohn’s disease sometimes feel more 

stress in their lives, which can make symptoms 

worse. Eating well, getting enough rest, and 

learning to relax may help you through stressful 

times. Support groups may help lower stress for 

people with Crohn’s disease. Ask your health care 

provider for help finding support groups. 

Even though you may need medicines and other 

treatments, you may feel well and be symptom-free 

for long periods of time. Most people with Crohn’s 

disease are able to work, raise families, and live full 

lives. 

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Is pregnancy safe for women with 

Crohn’s disease?

Many women with Crohn’s disease can become 

pregnant and have a baby. However, if you are a 

woman with Crohn’s disease, you should talk with 

your health care provider before getting pregnant. 

Points to Remember 

●	 Crohn’s disease is a disease that causes 

inflammation, or swelling, and irritation of 

any part of the digestive tract—also called the 

gastrointestinal (GI) tract. 

●	 People with Crohn’s disease may have a blood 

relative with the disease or another type of 

inflammatory bowel disease (IBD). 

●	 Symptoms of Crohn’s disease include abdominal 

pain, diarrhea, bleeding, weight loss, and fever. 

●	 A physical exam, blood tests, stool tests, and 

other tests are needed to diagnose Crohn’s 

disease. 

●	 Problems of Crohn’s disease include intestinal 

blockage, fistulas, abscesses, anemia, and slower 

growth in children. 

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●	 Doctors treat Crohn’s disease with medicines, 

surgery, diet, and nutrition. 

●	 People with Crohn’s disease should eat a healthy 

diet and avoid foods that make symptoms worse. 

●	 Quitting smoking can help make Crohn’s disease 

less severe. Ask your health care provider if you 

need help quitting smoking. 

●	 Support groups may help lower stress for people 

with Crohn’s disease. 

●	 Most people with Crohn’s disease are able to 

work, raise families, and live full lives. 

●	 Many women with Crohn’s disease can become 

pregnant and have a baby. You should talk 

with your health care provider before getting 

pregnant. 

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Hope through Research 

The National Institute of Diabetes and Digestive 

and Kidney Diseases’ (NIDDK’s) Division of 

Digestive Diseases and Nutrition supports research 

into digestive conditions, including Crohn’s 

disease. Researchers are working to better 

understand genes and Crohn’s disease. They are 

also studying new medicines and ways to deliver 

medicines that might be more effective than 

current treatments. 

Participants in clinical trials can play a more 

active role in their own health care, gain access to 

new research treatments before they are widely 

available, and help others by contributing to 

medical research. For information about current 

studies, visit www.ClinicalTrials.gov.
 

Pronunciation Guide 

abdominal (ab-DOM-ih-nul)

anus (AY-nuhss)

colonoscopy (KOH-lon-OSS-kuh-pee)

dehydration (DEE-hy-DRAY-shuhn)

fistulas (FISS-tyoo-luhs)

ileostomy (IL-ee-OSS-tuh-mee)

inflammation (IN-fluh-MAY-shuhn)

intestinal resection (in-TESS-tih-nuhl)

(ree-SEK-shuhn) 

osteomalacia (OSS-tee-oh-muh-LAY-shee-uh) 

osteoporosis (OSS-tee-oh-poh-ROH-siss) 

proctocolectomy (PROK-toh-koh-LEK-tuh-mee) 

sigmoidoscopy (SIG-moy-DOSS-kuh-pee) 

stricture (STRIK-choor) 

ulcerative colitis (UHL-sur-uh-tiv) (koh-LY-tiss) 

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For More Information 

Crohn’s & Colitis Foundation of America 

386 Park Avenue South, 17th Floor

New York, NY 10016

Phone: 1–800–932–2423 or 212–685–3440

Email: info@ccfa.org 

Internet: www.ccfa.org

Reach Out for Youth with Ileitis and Colitis, Inc. 

P.O. Box 857 

Bellmore, NY 11710 

Phone: 631–293–3102 

Email: info@reachoutforyouth.org 

Internet: www.reachoutforyouth.org 

United Ostomy Associations of America, Inc. 

P.O. Box 512 

Northfield, MN 55057–0512 

Phone: 1–800–826–0826 

Email: info@ostomy.org 

Internet: www.uoaa.org 

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Acknowledgments 

Publications produced by the Clearinghouse are 

carefully reviewed by both NIDDK scientists 

and outside experts. The original version of this 

publication was reviewed by Marla Dubinsky, 

M.D., Cedars-Sinai Medical Center. 

Thank you also to Jyl Pomeroy, B.S., R.N., at 

the Arlington Free Clinic, Arlington, VA, for 

facilitating field-testing of the original version of 

this publication. 

The U.S. Government does not endorse or favor any specific 

commercial product or company. Trade, proprietary, or 

company names appearing in this document are used only 

because they are considered necessary in the context of 

the information provided. If a product is not mentioned, 

the omission does not mean or imply that the product is 

unsatisfactory. 

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National Digestive Diseases 

Information Clearinghouse 

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Phone: 1–800–891–5389 

TTY: 1–866–569–1162 

Fax: 703–738–4929 

Email: nddic@info.niddk.nih.gov 

Internet: www.digestive.niddk.nih.gov 

The National Digestive Diseases Information Clearinghouse 

(NDDIC) is a service of the National Institute of Diabetes and 

Digestive and Kidney Diseases (NIDDK). The NIDDK is part of 

the National Institutes of Health of the U.S. Department of Health 

and Human Services. Established in 1980, the Clearinghouse 

provides information about digestive diseases to people with 

digestive disorders and to their families, health care professionals, 

and the public. The NDDIC answers inquiries, develops and 

distributes publications, and works closely with professional and 

patient organizations and Government agencies to coordinate 

resources about digestive diseases. 

This publication is not copyrighted. The Clearinghouse 

encourages users of this publication to duplicate and distribute 

as many copies as desired. 

This publication is available at www.digestive.niddk.nih.gov.

This publication may contain information about medications. 

When prepared, this publication included the most current 

information available. For updates or for questions about any 

medications, contact the U.S. Food and Drug Administration 

toll-free at 1–888–INFO–FDA (1–888–463–6332) or visit 

www.fda.gov. Consult your health care provider for more 

information. 
U.S. DEpArTmENT OF HEALTH 

AND HUmAN SErvICES 

National Institutes of Health 

NIH Publication No. 12 5774 

December 2011 

The NIDDK prints on recycled paper with bio based ink.