Functional diarrhea is chronic diarrhea without any clear cause. It is afunctionalgastrointestinaldisorder(FGD), meaning that it occurs without any other known signs of disease, injury, or structural problem.
Even if the cause of your functional diarrhea is unknown, your symptoms are real and should be treated. Over time, functional diarrhea can cause negative health effects, and you may benefit from lifestyle modifications or medical treatment.
This article explains what functional diarrhea is, how it is diagnosed, and how it is treated.
Functional Diarrhea Criteria
The Rome IV diagnostic criteria categorize FGD, including functional diarrhea, according to specific definitions.
Functional diarrhea criteria are:
Functional Diarrhea and Irritable Bowel Syndrome
Irritable bowel syndrome(IBS) is a type of FGD. When chronic diarrhea is the predominant symptom of IBS,diarrhea-predominant irritable bowel syndrome(IBS-D) may be diagnosed.
Both disorders involve frequent loose stools and may also involve such symptoms as gas, bloating,mucus in the stool, and feelings of urgency orincomplete evacuation, in which it feels like you have to use the toilet even if you just went.
Functional diarrhea is often considered a subtype of IBS-D.
Diagnosis
Functional diarrhea is diagnosed through a process of exclusion. This means that you can be diagnosed with functional diarrhea only after other digestive disorders or health problems have been ruled out.
Typically, your healthcare provider will take your health history, do a physical examination, and may order diagnostic lab tests, such as blood work and a stool sample analysis.
Other possible tests can include imaging examinations, such as abdominalcomputed tomography (CT), ultrasound, ormagnetic resonance imaging (MRI). Invasive tests such as acolonoscopyor anendoscopycan also help identify a cause.
Differential Diagnoses
Possible causes of diarrhea that need to be ruled out before a diagnosis of functional diarrhea is made include:
You may also be at higher risk of developing functional diarrheaafter having your gallbladder removed.
Treatment for Functional Diarrhea
Treatment for functional diarrhea typically aims to reduce symptoms through dietary changes. For example, this may include eliminating food triggers and slowly increasing fiber intake. If stress appears to be a possible contributing factor, stress-management strategies might be helpful.
Your healthcare provider may give you a prescription or recommendation for one of the following medications to reduce your diarrhea:
Does Diarrhea Cause Weight Loss?
5 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Schmulson MJ, Drossman DA.What is new in Rome IV.J Neurogastroenterol Motil. 2017;23(2):151-163. doi:10.5056/jnm16214Saha L.Irritable bowel syndrome: Pathogenesis, diagnosis, treatment, and evidence-based medicine.World J Gastroenterol. 2014;20(22):6759-73. doi:10.3748/wjg.v20.i22.6759Bul V, Sleesman B, Boulay B.Celiac disease presenting as profound diarrhea and weight loss - a celiac crisis.Am J Case Rep. 2016;17:559-61. doi:10.12659/AJCR.898004Deng Y, Misselwitz B, Dai N, Fox M.Lactose intolerance in adults: Biological mechanism and dietary management.Nutrients. 2015;7(9):8020-35. doi:10.3390/nu7095380Hong KS, Kim JS.Rifaximin for the treatment of acute infectious diarrhea.Therap Adv Gastroenterol. 2011;4(4):227-35. doi:10.1177/1756283X11398734Additional ReadingClevers E, Whitehead WE, Palsson OS, et al.Factor Analysis Defines Distinct Upper and Lower Gastrointestinal Symptom Groups Compatible With Rome IV Criteria in a Population-based Study. Clin Gastroenterol Hepatol. 2018 Aug;16(8):1252-1259.e5. doi: 10.1016/j.cgh.2018.02.042. Epub 2018 Mar 3.
5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Schmulson MJ, Drossman DA.What is new in Rome IV.J Neurogastroenterol Motil. 2017;23(2):151-163. doi:10.5056/jnm16214Saha L.Irritable bowel syndrome: Pathogenesis, diagnosis, treatment, and evidence-based medicine.World J Gastroenterol. 2014;20(22):6759-73. doi:10.3748/wjg.v20.i22.6759Bul V, Sleesman B, Boulay B.Celiac disease presenting as profound diarrhea and weight loss - a celiac crisis.Am J Case Rep. 2016;17:559-61. doi:10.12659/AJCR.898004Deng Y, Misselwitz B, Dai N, Fox M.Lactose intolerance in adults: Biological mechanism and dietary management.Nutrients. 2015;7(9):8020-35. doi:10.3390/nu7095380Hong KS, Kim JS.Rifaximin for the treatment of acute infectious diarrhea.Therap Adv Gastroenterol. 2011;4(4):227-35. doi:10.1177/1756283X11398734Additional ReadingClevers E, Whitehead WE, Palsson OS, et al.Factor Analysis Defines Distinct Upper and Lower Gastrointestinal Symptom Groups Compatible With Rome IV Criteria in a Population-based Study. Clin Gastroenterol Hepatol. 2018 Aug;16(8):1252-1259.e5. doi: 10.1016/j.cgh.2018.02.042. Epub 2018 Mar 3.
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Schmulson MJ, Drossman DA.What is new in Rome IV.J Neurogastroenterol Motil. 2017;23(2):151-163. doi:10.5056/jnm16214Saha L.Irritable bowel syndrome: Pathogenesis, diagnosis, treatment, and evidence-based medicine.World J Gastroenterol. 2014;20(22):6759-73. doi:10.3748/wjg.v20.i22.6759Bul V, Sleesman B, Boulay B.Celiac disease presenting as profound diarrhea and weight loss - a celiac crisis.Am J Case Rep. 2016;17:559-61. doi:10.12659/AJCR.898004Deng Y, Misselwitz B, Dai N, Fox M.Lactose intolerance in adults: Biological mechanism and dietary management.Nutrients. 2015;7(9):8020-35. doi:10.3390/nu7095380Hong KS, Kim JS.Rifaximin for the treatment of acute infectious diarrhea.Therap Adv Gastroenterol. 2011;4(4):227-35. doi:10.1177/1756283X11398734
Schmulson MJ, Drossman DA.What is new in Rome IV.J Neurogastroenterol Motil. 2017;23(2):151-163. doi:10.5056/jnm16214
Saha L.Irritable bowel syndrome: Pathogenesis, diagnosis, treatment, and evidence-based medicine.World J Gastroenterol. 2014;20(22):6759-73. doi:10.3748/wjg.v20.i22.6759
Bul V, Sleesman B, Boulay B.Celiac disease presenting as profound diarrhea and weight loss - a celiac crisis.Am J Case Rep. 2016;17:559-61. doi:10.12659/AJCR.898004
Deng Y, Misselwitz B, Dai N, Fox M.Lactose intolerance in adults: Biological mechanism and dietary management.Nutrients. 2015;7(9):8020-35. doi:10.3390/nu7095380
Hong KS, Kim JS.Rifaximin for the treatment of acute infectious diarrhea.Therap Adv Gastroenterol. 2011;4(4):227-35. doi:10.1177/1756283X11398734
Clevers E, Whitehead WE, Palsson OS, et al.Factor Analysis Defines Distinct Upper and Lower Gastrointestinal Symptom Groups Compatible With Rome IV Criteria in a Population-based Study. Clin Gastroenterol Hepatol. 2018 Aug;16(8):1252-1259.e5. doi: 10.1016/j.cgh.2018.02.042. Epub 2018 Mar 3.
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