Why Diagnosing IBS Can Take Time

Irritable bowel syndrome (IBS) is a common condition that affects your large intestine (colon). It can cause cramping, bloating, pain, gas, constipation, diarrhea, and other changes that involve your bowel.

Your doctor can help you figure out if IBS is behind your issues. But it may take a while to know for sure.

You must have had symptoms for several months.

For your doctor to think you might have IBS, you have to have had at least one of these for at least 6 months:

  • Belly pain or discomfort
  • Bloating
  • A change in your bowel habits, like diarrhea or constipation, loose stools, or having to use the bathroom more often than usual           

If your symptoms have only been around a few weeks, your doctor may want to "watch and wait" to see if you still have them after 6 months.

Your doctor may ask you to keep a "symptom diary" for a while.

Your doctor will want to know if you feel better after a bowel movement. This is one sign of IBS. Another is belly pain or stool issues at the same time your stool changes shape or form or you have to go to the bathroom more often or less often.

It can be hard to remember all your symptoms. Your doctor may ask you to write down what you notice on a calendar or in a notebook.

Your doctor may ask you to change your diet to see if that helps.

Some people can't digest lactose, a natural sugar found in dairy products. This is called lactose intolerance. It can cause many of the same things IBS does, like belly pain, gas, and diarrhea.

Your doctor might want you to stay away from dairy for a while to see if you feel better.

He also might recommend something called a low FODMAP diet. It cuts down on carbs that are hard to digest, like wheat and beans, along with certain fruits and vegetables. It also limits dairy, including cheese, milk, yogurt, and sour cream.

You may need several tests to rule out other health problems.

If you've lost weight without trying or you have blood in your rectum or stool, your doctor may want to do some tests. These help rule out conditions like celiac disease. They're helpful too if you have a family history of inflammatory bowel disease or certain cancers. 

Some tests your doctor may recommend include a blood test, a stool test, and a colonoscopy (your doctor uses a long, flexible tube to look inside your rectum and colon to check for irritated tissue, polyps, cancerous tumors, and other problems).

WebMD Medical Reference Reviewed by Minesh Khatri, MD on July 07, 2019

Sources

SOURCES:

Cleveland Clinic: "Irritable Bowel Syndrome."

NHS (U.K.): "Irritable Bowel Syndrome (IBS)."

National Institute of Diabtes and Digestive and Kidney Diseases: "Diagnosis of Irritable Bowel Syndrome."

Arun Swaminath, MD, director of the inflammatory bowel disease program at Lenox Hill Hospital in New York City.

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