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Inflammatory Bowel Disease

  • Umbrella term for two conditions that cause chronic inflammation in the digestive system: ulcerative colitis and Crohn’s disease
  • Abdominal cramps and pain as well as diarrhea are symptoms of both conditions
  • Medications, bowel rest, and, in some cases, surgery are treatment options
  • Involves Digestive Diseases

Inflammatory Bowel Disease


If you find you are arranging your life around bouts of diarrhea and painful abdominal cramping, you may have inflammatory bowel disease (IBD). The term describes a category of chronic inflammatory diseases that affect the intestines in similar, yet different ways. The specific conditions that cause chronic bouts of these symptoms are ulcerative colitis and Crohn’s disease.  

IBD affects men and women in roughly equal numbers. It most commonly gets diagnosed between ages 15 and 30, although some people are diagnosed later in life, in their 60s or 70s. Between 600,000 and 900,000 Americans have ulcerative colitis, according to research, while slightly fewer Americans—but still more than 500,000—have Crohn’s disease.  

Medication can be helpful in treating and preventing IBD flare-ups. Some people with ulcerative colitis may need surgery (to remove the colon and rectum) after living with the condition for a number of years. Similarly, surgery may also be needed to treat complications from Crohn’s disease. Both conditions may increase the risk of colorectal cancer.  

“To prevent complications from Crohn’s disease or ulcerative colitis, treatment should target an improvement in the person’s symptoms but also target an improvement in intestinal inflammation,” says Jill Gaidos, MD, an IBD specialist. “At the Yale IBD Center, we routinely monitor our patients for symptoms of active inflammation while also monitoring for inflammation using lab tests, endoscopy, or imaging. This is called a “treat to target” approach to IBD management.”  

What is inflammatory bowel disease?

Inflammatory bowel disease is the umbrella term for two conditions that cause chronic inflammation within the digestive system: ulcerative colitis and Crohn’s disease. Both conditions cause diarrhea and abdominal discomfort, and both occur in alternating periods of flare-up (with symptoms) and remission (without symptoms). Importantly, studies have shown that symptoms do not always correlate with active inflammation, so continuing your medications even when you feel well is very important.

Each type of IBD affects the body differently:  

  • Ulcerative colitis. Inflammation causes damage to contiguous areas of the rectum and the inner lining of the colon.
  • Crohn’s disease. This condition may occur anywhere in the digestive tract, from the mouth to the anus, bringing inflammation that damages some patches of tissue while sparing others. Healthy and diseased tissue typically sit side-by-side. 

In both conditions, the inflammation causes congestion in the lining of the intestines, ulcers, and irritation that damages tissue in the digestive system. This is what causes bleeding and leads to diarrhea and other symptoms.  

Both ulcerative colitis and Crohn’s disease occur on a spectrum from mild to moderate to severe, so some people experience fewer symptoms and less damage than others.

What causes inflammatory bowel disease?

The exact causes of ulcerative colitis and Crohn’s disease are unknown, but certain factors make people more likely to develop IBD:  

  • An overactive immune system. The immune system may respond in an exaggerated way to perceived threats, causing it to attack the digestive system unnecessarily. This may cause inflammation within the intestines. If the digestive system is chronically inflamed, IBD may develop.
  • Different gut flora. People with IBD don’t have the same proportion of “helpful” and “harmful” bacteria in the intestines as healthy individuals. This may cause gut inflammation, influencing the development of disease.
  • A family history. Five to 10% of people with IBD have a family history of the condition. Several genes have been identified that are linked to IBD. People who have a first-degree relative (parent, child, sibling) with IBD are 10 to 15 times more likely to develop ulcerative colitis or Crohn’s disease, compared to the general population. The risk, however, is still low overall.

What are the symptoms of inflammatory bowel disease?

Though there are similarities, ulcerative colitis and Crohn’s disease each present with their own constellation of symptoms.  

For ulcerative colitis, the most common symptoms include:

  • Bloody diarrhea
  • A bleeding rectum
  • The frequent urge to have bowel movements
  • Mucus that is passed with bowel movements
  • Abdominal cramps and pain 

Less commonly, those with more severe ulcerative colitis may also experience fatigue, nausea and/or vomiting, fever, and unintended weight loss.  

It’s important to note that people with ulcerative colitis that only involves the rectum may have constipation instead of diarrhea.

For Crohn’s disease, the most common symptoms include:

  • Diarrhea (which may or may not be bloody)
  • Unintended weight loss
  • Abdominal cramps and pain

Those with more severe Crohn’s disease may also experience these less-common side effects:

  • Fatigue
  • Nausea
  • Fever
  • Loss of appetite
  • Anemia
  • Eye pain or redness
  • Joint soreness or pain
  • Sores within the mouth
  • Red sores on the skin

How is inflammatory bowel disease diagnosed?

When you visit your doctor with symptoms that suggest IBD, you’ll be asked very specific questions about your symptoms, including the frequency of diarrhea, whether it’s accompanied by bleeding and if there’s abdominal pain or cramping. The doctor will also ask questions about your personal and family medical history.  

The doctor will also perform a physical exam, checking your abdomen for bloating and pain, then listening to digestive sounds with a stethoscope. Some doctors may perform a digital rectal exam to check for blood in the stool.  

Doctors may also order tests to diagnose IBD, including:

  • A stool sample analysis
  • Bloodwork
  • Endoscopy (colonoscopy, flexible sigmoidoscopy or enteroscopy), which shows the intestines from within 

For Crohn’s disease, doctors may also order an endoscopy, as well as an MRI, CT scan, or an X-ray of the upper gastrointestinal tract.

How is inflammatory bowel disease treated?

Doctors use a variety of approaches to help patients reduce gastrointestinal inflammation and get their IBD symptoms under control. Medication can help put both ulcerative colitis and Crohn’s disease into remission for periods of time, but it’s important to note that some people have better responses to certain medications than others. Talk to your doctor if you don’t feel like your medication is working for you.  


Medications that can be helpful for IBD symptoms include:

  • Anti-diarrheal medication, but only in cases where the patient has no or only mild intestinal inflammation.
  • Anti-spasmodics, which reduce intestinal spasms and can minimize abdominal cramps
  • Antibiotics, which may be used as a short-term treatment to alter the gut flora in a helpful way in some people with Crohn’s disease
  • Aminosalicylates, anti-inflammatory drugs that can help people with mild-to-moderate ulcerative colitis achieve and maintain remission
  • Corticosteroids, which can be used as a short-term treatment for flare-ups of both ulcerative colitis and Crohn’s disease
  • Immunotherapy medications, which suppress the immune system and may help people with IBD achieve and/or maintain remission. This includes a wide range of medications with several different mechanisms of action. 

Bowel rest

For some people with severe Crohn’s disease, bowel rest—only consuming pre-approved clear liquids, or receiving nutrition through a feeding tube or IV—may be helpful. When the intestines are given time away from digesting, they may begin to heal.  


People with ulcerative colitis or Crohn’s disease may need different types of surgery:

  • Crohn’s disease. About half of people with Crohn’s disease require surgery within the first decade of diagnosis. Sometimes, it’s to manage fistulas—abnormal passageways that develop between the intestines and an adjacent organ; other times, it’s to manage abscesses—swollen, pus-filled areas of infection that may develop. Surgery may also be advised when an area of inflammation has healed and become so narrow that it causes an obstruction that blocks the intestines. Patients with prolonged Crohn’s disease may need more than one surgery over their lifetimes.
  • Ulcerative colitis. About 40% of people with severe ulcerative colitis eventually have surgery to remove the colon and rectum, which technically cures the condition because they no longer have a colon. However, most people will still have more frequent bowel movements after surgery then before they were diagnosed with ulcerative colitis. In some of these cases, the surgeon is able to create a passageway from the small intestine to the anus, enabling the patient to have normal bowel movements. Others will require ostomy bags to collect their waste. The process to remove the colon and create an ileoanal anastomosis (or a J-pouch) is typically a 2- or 3-stage surgery that requires a temporary ileostomy. In some cases, patients are not candidates for the J-pouch and do require a permanent ileostomy.     

An unusual but very serious (and potentially fatal) complication that can arise from ulcerative colitis is called “toxic megacolon.” This happens when the colon stops working and expands in size significantly, to the point where it may rupture if left untreated. If initial treatments aren’t helpful, emergency surgery is recommended. 

What is the outlook for people with inflammatory bowel disease?

Because of the nature of its symptoms and the fact that people with the condition often eventually require one or more surgeries, people with IBD may experience a poorer quality of life than their healthier peers.    

As far as life expectancy, this varies depending on which condition a person has. Those with Crohn’s disease may have a somewhat shorter lifespan, due to complications from the disease. People with ulcerative colitis may have a normal life expectancy, in part because of advancements in treatment in recent years.

What stands out about Yale Medicine’s approach to IBD treatment?

“At the Yale IBD Center, we work closely with the colorectal surgeons and take a multidisciplinary approach to caring for our IBD patients. We are dedicated to changing the natural history of IBD. We are working to diagnose IBD as early as possible and to ensure that our IBD medications are not only treating symptoms but also intestinal inflammation, which is the cause of so many complications that we see with IBD,” says Dr. Gaidos. “We not only stay up-to-date on all new IBD therapies, but we also have an active clinical trials program for both ulcerative colitis and Crohn’s disease so that our patients have access to potential treatment options that are otherwise unavailable.”