Inflammatory bowel disease (IBD) involves chronic inflammation of all or part of your digestive tract. IBD primarily includes ulcerative colitis and Crohn’s disease. IBD can be painful and debilitating, and sometimes leads to life-threatening complications.

Ulcerative colitis  is an inflammatory bowel disease that causes long-lasting inflammation in part of your digestive tract. Symptoms usually develop over time, rather than suddenly. Ulcerative colitis usually affects only the innermost lining of your large intestine (colon) and rectum. It occurs only through continuous stretches of your colon.

Crohn’s disease is an inflammatory bowel disease that causes inflammation anywhere along the lining of your digestive tract, and often spreads deep into affected tissues. This can lead to abdominal pain, severe diarrhea and even malnutrition. The inflammation caused by Crohn’s disease can involve different areas of the digestive tract in different people.

Inflammatory bowel disease symptoms vary, depending on the severity of inflammation and where it occurs.

Ulcerative colitis is classified according to its signs and symptoms:

• Ulcerative proctitis. In this form of ulcerative colitis, inflammation is confined to the area closest to the anus (rectum), and for some people, rectal bleeding may be the only sign of the disease. Others may have rectal pain, a feeling of urgency or have frequent, small bowel movements. This form of ulcerative colitis tends to be the mildest.
• This form involves the rectum and the lower end of the colon, known as the sigmoid colon. Bloody diarrhea, abdominal cramps and pain, and an inability to move the bowels in spite of the urge to do so (tenesmus) are common problems associated with this form of the disease.
• Left-sided colitis. As the name suggests, inflammation extends from the rectum up through the sigmoid and descending colon, which are located in the upper left part of the abdomen. Signs and symptoms include bloody diarrhea, abdominal cramping and pain on the left side, and unintended weight loss.
• Affecting more than the left colon and often the entire colon, pancolitis causes bouts of bloody diarrhea that may be severe, abdominal cramps and pain, fatigue, and significant weight loss.
• Fulminant colitis. This rare, life-threatening form of colitis affects the entire colon and causes severe pain, profuse diarrhea and, sometimes, dehydration and shock. People with fulminant colitis are at risk of serious complications, including colon rupture and toxic megacolon, a condition that causes the colon to rapidly expand.

The course of ulcerative colitis varies, with periods of acute illness often alternating with periods of remission. Most people with a milder condition, such as ulcerative proctitis, won’t go on to develop more-severe signs and symptoms.

Inflammation of Crohn’s disease may involve different parts of the digestive tract in different people. The most common areas affected by Crohn’s disease are the last part of the small intestine called the ileum and the colon. Inflammation may be confined to the bowel wall, which can lead to scarring (stenosis), or inflammation may spread through the bowel wall (fistula).

Signs and symptoms of Crohn’s disease can range from mild to severe and may develop gradually or come on suddenly, without warning. Signs and symptoms may include:

• The inflammation that occurs in Crohn’s disease causes cells in the affected areas of your intestine to secrete large amounts of water and salt. Because the colon can’t completely absorb this excess fluid, you develop diarrhea. Intensified intestinal cramping also can contribute to loose stools. Diarrhea is a common problem for people with Crohn’s.
• Abdominal pain and cramping. Inflammation and ulceration may cause the walls of portions of your bowel to swell and eventually thicken with scar tissue. This affects the normal movement of contents through your digestive tract and may lead to pain and cramping. Mild Crohn’s disease usually causes slight to moderate intestinal discomfort, but in more-serious cases, the pain may be severe and include nausea and vomiting.
• Blood in your stool. Food moving through your digestive tract may cause inflamed tissue to bleed, or your bowel may also bleed on its own. You might notice bright red blood in the toilet bowl or darker blood mixed with your stool. You can also have bleeding you don’t see (occult blood).
• Crohn’s disease and ulcerative colitis can cause small sores on the surface of the intestine that eventually become large ulcers that penetrate deep into — and sometimes through — the intestinal walls. You may also have ulcers elsewhere, including in your mouth similar to canker sores.
• Reduced appetite and weight loss. Abdominal pain and cramping and inflammation of your bowel wall can affect both your appetite and your ability to digest and absorb food.

People with severe Crohn’s disease may also experience:

• Fever
• Fatigue
• Arthritis
• Eye inflammation
• Skin disorders
• Inflammation of the liver or bile ducts
• Delayed growth or sexual development, in children

No one is quite sure what triggers inflammatory bowel disease, but there’s a consensus as to what doesn’t. Researchers no longer believe that diet and stress are main causes, although stress can often aggravate symptoms. Instead, current thinking focuses on the:

• Immune system. Some scientists think a virus or bacterium may trigger IBD. The digestive tract becomes inflamed when your immune system tries to fight off the invading microorganism (pathogen). It’s also possible that inflammation may stem from an autoimmune reaction in which your body mounts an immune response even though no pathogen is present.
• Because you’re more likely to develop IBD if you have a parent or sibling with the disease, scientists suspect that genetic makeup may play a role. However, most people who have IBD don’t have a family history of the disorder.

Inflammatory bowel disease affects about the same number of women and men. Risk factors may include:

• Inflammatory bowel disease usually begins before the age of 30. But, it can occur at any age, and some people may not develop the disease until their 50s or 60s.
• Family history. You’re at higher risk if you have a close relative, such as a parent, sibling or child, with the disease.
• Cigarette smoking. Cigarette smoking is the most important controllable risk factor for developing Crohn’s disease. It leads to more-severe symptoms and higher risk of complications.
• Some pain relievers. These medications include ibuprofen and aspirin. These medications have been shown to cause gastrointestinal ulceration and may make existing IBD worse. Acetaminophen does not have this effect.

Inflammatory bowel disease may lead to one or more of the following complications:

• Bowel obstruction.Crohn’s disease affects the entire thickness of the intestinal wall. Over time, parts of the bowel can thicken and narrow, which may block the flow of digestive contents through the affected part of your intestine. Some cases require surgery to remove the diseased portion of your bowel.
• Chronic inflammation can lead to open sores (ulcers) anywhere in your digestive tract, including your mouth and anus, and in the genital area (perineum) and anus. Bleeding may result.
• Sometimes ulcers can extend completely through the intestinal wall, creating a fistula. A fistula is an abnormal connection between different parts of your intestine, between your intestine and skin, or between your intestine and another organ, such as the bladder or vagina. When internal fistulas develop, food may bypass areas of the bowel that are necessary for absorption. An external fistula can cause continuous drainage of bowel contents to your skin, and in some cases, a fistula may become infected and form an abscess, a problem that can be life-threatening if left untreated. Fistulas around the anal area (perianal) are the most common kind of fistula.
• Anal fissure. This is a crack, or cleft, in the anus or in the skin around the anus where infections can occur. It’s often associated with painful bowel movements. This may lead to a perianal fistula.
• Diarrhea, abdominal pain and cramping may make it difficult for you to eat or for your intestine to absorb enough nutrients to keep you nourished. Additionally, anemia is common in people with IBD.
• Colon Having IBD disease that affects your colon increases your risk of colon cancer.
• Other health problems. In addition to inflammation and ulcers in the digestive tract, IBD can cause problems in other parts of the body, such as arthritis, inflammation of the eyes or skin, clubbing of the fingernails, kidney stones, gallstones, and, occasionally, inflammation of the bile ducts. People with long-standing IBD also may develop osteoporosis, a condition that causes weak, brittle bones.

Your doctor will likely diagnose inflammatory bowel disease only after ruling out other possible causes for your signs and symptoms, including ischemic colitis, infection, irritable bowel syndrome (IBS), diverticulitis and colon cancer. To help confirm a diagnosis of IBD, you may have one or more of the following tests and procedures:

• Blood tests.
• Stool sample.
•  This exam allows your doctor to view the inside of your entire colon using a thin, flexible, lighted tube with an attached camera. During the procedure, your doctor can also take small samples of tissue (biopsy) for laboratory analysis. Sometimes a tissue sample can help confirm a diagnosis.
• X-ray. A standard X-ray of your abdominal area may be done to rule out toxic megacolon or a perforation of the colon if these conditions are suspected because of severe symptoms.
• Computerized tomography (CT) scan. A CT scan of your abdomen or pelvis may be performed if your doctor suspects a complication from ulcerative colitis or inflammation of the small intestine that might suggest Crohn’s disease. A CT scan may also reveal how much of the colon is inflamed.
• Magnetic resonance imaging (MRI).
• Capsule endoscopy. If you have signs and symptoms that suggest Crohn’s disease but other diagnostic tests are negative, your doctor may perform capsule endoscopy. For this test you swallow a capsule that has a tiny camera in it. The camera takes pictures as it moves through your digestive tract, and the images are transmitted to a computer that you wear on your belt. Your doctor later downloads the images, which are then displayed on a monitor and checked for signs of Crohn’s disease. Once it’s made the trip through your digestive system, the camera exits your body painlessly in your stool.
• Double-balloon endoscopy. For this test, a longer scope is used to look further into the small bowel where standard endoscopes don’t reach. This technique is useful when capsule endoscopy shows abnormalities but the diagnosis is still in question. It allows for biopsy of the abnormal area. It’s usually performed in specialized endoscopy centers.
• Small bowel imaging. This test looks at the part of the small bowel that can’t be seen by colonoscopy. You drink a solution containing barium, then X-ray, CT or MRI images are taken of your small intestine. The test can help locate areas of narrowing or inflammation in the small bowel that are seen in Crohn’s disease. The test can also help your doctor determine which type of inflammatory bowel disease you have.

The goal of inflammatory bowel disease treatment is to reduce the inflammation that triggers your signs and symptoms. In the best cases, this may lead not only to symptom relief but also to long-term remission. IBD treatment usually involves either drug therapy or surgery.

Anti-inflammatory drugs are often the first step in the treatment of inflammatory bowel disease. They include:

• Mesalamine

These drugs also reduce inflammation, but they target your immune system rather than treating inflammation itself. Because immune suppressors can be effective in treating ulcerative colitis, scientists theorize that damage to digestive tissues is caused by your body’s immune response to an invading virus or bacterium or even to your own tissue. By suppressing this response, inflammation is also reduced. Immune system suppressors are associated with a small risk of developing cancer, such as lymphoma. Immunosuppressant drugs include:

• Azathioprine
• Infliximab . This drug is specifically for those with moderate to severe ulcerative colitis who don’t respond to or can’t tolerate other treatments. It works quickly to bring on remission, especially for people who haven’t responded well to corticosteroids. It works by neutralizing a protein produced by your immune system known as tumor necrosis factor (TNF).

Some people with heart failure, people with multiple sclerosis, and people with cancer or a history of cancer can’t take infliximab. The drug has been linked to an increased risk of infection, especially tuberculosis and reactivation of viral hepatitis, and may increase your risk of blood problems and cancer. You’ll need to have a skin test for tuberculosis, a chest X-ray and a test for hepatitis B before taking infliximab.

• Adalimumab
• Methotrexate

Antibiotics can reduce the amount of drainage and sometimes heal fistulas and abscesses in people with Crohn’s disease. Researchers also believe antibiotics help reduce harmful intestinal bacteria and suppress the intestine’s immune system, which can trigger symptoms. However, there’s no strong evidence that antibiotics are effective for Crohn’s disease. Frequently prescribed antibiotics include:

• Metronidazole
• Ciprofloxacin

In addition to controlling inflammation, some medications may help relieve your signs and symptoms. Depending on the severity of your inflammatory bowel disease, your doctor may recommend one or more of the following:

• Anti-diarrheals.
• Laxatives
• Pain relievers.
• Iron supplements.
• B-12 shots.
• Calcium and vitamin D supplements.

If diet and lifestyle changes, drug therapy, or other treatments don’t relieve your IBD signs and symptoms, your doctor may recommend surgery.

• Surgery for ulcerative colitis. Surgery can often eliminate ulcerative colitis. But that usually means removing your entire colon and rectum (proctocolectomy). In the past, after this surgery you would wear a small bag over an opening in your abdomen (ileostomy) to collect stool. But a procedure called ileoanal anastomosis eliminates the need to wear a bag and is the preferred procedure for most people. Your surgeon constructs a pouch from the end of your small intestine. The pouch is then attached directly to your anus. This allows you to expel waste more normally.
• Surgery for Crohn’s disease. In Crohn’s disease, surgery can provide years of remission at best. At the least, it may provide a temporary improvement in your signs and symptoms. During surgery, your surgeon removes a damaged portion of your digestive tract and then reconnects the healthy sections. In addition, surgery may also be used to close fistulas and drain abscesses. A common procedure for Crohn’s is strictureplasty, which widens a segment of the intestine that has become too narrow.

People who have inflammatory bowel disease have an increased risk of colon cancer. Talk with your doctor about how often you should be screened.

There’s no firm evidence that what you eat causes inflammatory bowel disease. But certain foods and beverages can aggravate your symptoms, especially during a flare-up. It’s a good idea to try eliminating from your diet anything that seems to make your signs and symptoms worse. Here are some suggestions:

• Limit dairy products
• Increase fiber in diet
• Eat small meals. You may find that you feel better eating five or six small meals rather than two or three larger ones.
• Drink plenty of liquids. .
• Consider multivitamins.
• Talk to a dietitian. If you begin to lose weight or your diet has become very limited, talk to a registered dietitian.

Smoking increases your risk of developing Crohn’s disease, and once you have it, smoking can make the condition worse. People with Crohn’s disease who smoke are more likely to have relapses, need medications and repeat surgeries. Quitting smoking can improve the overall health of your digestive tract, as well as provide many other health benefits.

Although stress doesn’t cause inflammatory bowel disease, it can make your signs and symptoms much worse and may trigger flare-ups.