Types Of IBS

There are 3 types of irritable bowel syndrome (IBS). Each type is based on different patterns or changes in bowel movements.1

Doctors use what is called the Rome IV criteria to decide which type of IBS you have.1 It looks at the percentage of time a person experiences very hard or very loose stools. This is a significant change because many people can go long periods of time without an abnormal bowel movement.1

Diagnosing IBS

A diagnosis of IBS is made based on a report of bowel habits that start at least 6 months prior to diagnosis. The diagnosis considers recurrent stomach pain for at least 1 day per week during the 3 months before diagnosis combined with at least 2 of the following:1

  • Pain can increase or be unchanged related to a bowel movement
  • Associated with a change in stool frequency
  • Associated with a change in stool form or appearance

IBS subtypes

Doctors at one time thought of IBS as very separate types. Now they recognize that a person's IBS may change from mostly IBS with constipation to IBS with diarrhea, and back again. Rome IV updates recognize that these disorders exist as a continuum rather than as simple subtypes.1

IBS with constipation (IBS-C)

IBS-C is characterized by:3

  • Hard stools more than 25 percent of the time and loose stools less than 25 percent of the time
  • Account for up to 33 percent of all IBS cases

Approximately 25 percent of people with IBS-C reported bothersome symptoms as abdominal pain, straining, infrequent stools, bloating and/or gas. Pain, gas, and bloating, were reported by constipation sufferers as occurring on average of over 200 times a year.1

IBS with diarrhea (IBS-D)

IBS-D is characterized by:3

  • Loose stools more than 25 percent of the time and hard stools less than 25 percent of the time
  • Account for up to 33 percent of all IBS cases

Forty-three percent of IBS-D sufferers report that the most bothersome symptom they experience is abdominal pain or discomfort. Thirty-seven percent reported sudden urges to have bowel movements. People with IBS-D have symptoms of gas and frequent stools over 200 times a year.4

IBS with mixed bowel habits (IBS-M)

IBS-M is characterized by:1,3

  • Both hard and soft stools more than 25 percent of the time
  • Account for 33 to 50 percent of all IBS cases

This type of IBS can be used to describe people’s IBS symptoms at a specific point in time. For this group, bowel habits often vary.1

IBS unclassified (IBS-U)

IBS-U is characterized by people who meet the diagnostic criteria of IBS but whose bowel habits do not fit one of the other subtypes.1

Post-infectious IBS

Symptoms of IBS may occur after an intestinal infection. This type of IBS is usually triggered by something else.3

Post-diverticulitis IBS

Symptoms of diverticulitis may come and go, often for short periods of time.3 The symptoms include:3

  • Left-sided abdominal pain
  • Fever
  • Tender inflammatory mass in the left lower portion of the abdominal area

Post-diverticulitis IBS occurs after symptoms of diverticulitis. Therefore, diverticulitis may increase the risk for IBS.3

Other names for IBS

IBS is sometimes called IBS colitis, mucous colitis, spastic colon, nervous (irritable) colon, and spastic bowel.2,5

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Written by: Linda Saxl Minton | Last reviewed: April 2020