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Diarrheal Diseases – Acute and Chronic
Diarrheal Diseases Overview
Symptoms
- What are the symptoms of diarrhea?
Diarrheal stools are those that are loose, watery, and take shape of the container. Some people consider diarrhea to be an increase in the number of stools, but stool consistency is really most important. Associated symptoms can include cramping, abdominal pain, fever, nausea, vomiting, fatigue, urgent stools, or incontinence (losing control of stools). Diarrhea can also lead to weight loss and difficulty absorbing nutrition from food, among other symptoms.
If you have weight loss, diarrhea that wakes you up at night, or blood in the stools, these can be serious signs. It’s very important that you see a healthcare provider. You should also tell your provider if you experience bulky, greasy or very foul smelling stools.
- What is the difference between acute and chronic diarrhea?
Acute diarrhea is very common in the United States – only colds happen more often. Worldwide, it is one of the most common reasons that young children under 4 years old become seriously sick, especially in developing countries.
- Acute diarrhea: lasts less than 2 weeks.
- Persistent diarrhea: lasts 2 to 4 weeks.
- Chronic diarrhea: lasts more than 4 weeks.
If you have severe acute diarrhea, persistent diarrhea, or chronic diarrhea, it’s very important to talk to a doctor.
Causes
- What causes acute diarrhea?
Most acute diarrhea is caused by viruses (viral gastroenteritis). This is often a watery diarrhea. In children, rotavirus is the most common cause. In adults, norovirus is most common. Bacteria are a common cause of traveler’s diarrhea.
- What causes chronic diarrhea?
Chronic diarrhea is classified into 3 main types: watery, fatty (malabsorptive), or inflammatory. These categories are based on stool appearance and underlying cause of the diarrhea.
- Watery diarrhea: Can be divided into secretory, osmotic, and functional diarrhea. Causes include microscopic colitis, carbohydrate malabsorption (lactose, sorbitol, or fructose malabsorption), bile salt malabsorption, endocrine problems (such as diabetes), medications (antibiotics are a common cause), laxative use, and irritable bowel syndrome.
- Fatty (malabsorptive) diarrhea: Fat in the stools with stools that may look greasy. Digestion of fats is interrupted due to small bowel disease or low pancreatic enzyme levels. Common causes include celiac disease, pancreatic insufficiency from chronic pancreatitis, eosinophilic gastrointestinal disease, and giardia infection.
- Inflammatory diarrhea Blood and mucus in the stool. This can be caused by inflammatory bowel disease (Crohn’s disease or ulcerative colitis), certain types of infections, colon cancer, radiation therapy, or ischemia (colon does not receive enough blood flow).
Risk Factors
- What are the risk factors for diarrhea?
Acute diarrhea is often caused by exposure to infections. Hand washing and hygiene are important to prevent infection. Washing with soap and water is best, as some alcohol-based hand sanitizers may not kill viruses or some bacteria. If soap and water are not available, use hand sanitizer containing at least 60% alcohol.
Acute bloody diarrhea is often caused by bacteria. The best way to prevent this is to avoid eating and drinking contaminated or raw foods and beverages. When traveling, avoid untreated tap water, ice, unpasteurized dairy products, and raw or undercooked meats.
Medications such as antibiotics and drugs that contain magnesium products are a common cause of diarrhea. Changes in diet may also lead to diarrhea. Consider coffee, tea, colas, diet foods, gums or mints that contain poorly absorbed sugars as possible causes.
Screening/Diagnosis
- How is diarrhea diagnosed?
Most episodes of acute diarrhea resolve quickly without antibiotic therapy and with simple dietary modifications. See a doctor if you feel ill or experience bloody diarrhea, severe abdominal pain or diarrhea lasting greater than 48 hours. With mild acute diarrhea, no laboratory evaluation is needed because the illness generally resolves quickly. Your doctor may perform stool tests if your diarrhea is severe or bloody or if you traveled to an area where infections are more common. If you have severe diarrhea, blood tests may be helpful to guide replacement of fluid and electrolytes.
If you have chronic diarrhea, your doctor will want to do further testing to better understand the reason for diarrhea. These can include a blood count to look for anemia and infection, an electrolyte and kidney function panel to assess for electrolyte abnormalities and renal insufficiency, and albumin, vitamin or micronutrient testing to assess your nutrition status.
Testing a sample of your stool may be needed to better understand the cause of your diarrhea. Stool can be tested for infections, fat, microscopic amounts of blood, and white blood cells. This will help to determine if the diarrhea is fatty, inflammatory, or watery.
Other testing may include an upper endoscopy, colonoscopy, or flexible sigmoidoscopy. These procedures allow direct visualization of the intestines. Biopsies or samples from the lining of the intestine can be taken and evaluated under the microscope to better understand the cause of diarrhea. A video capsule endoscopy (a pill capsule that takes pictures of the small intestine) or double-balloon enteroscopy (a special scope designed to evaluate the small intestine) may be needed in some cases.
Radiology testing with ultrasound or CT scan of the abdomen may also be helpful. These tests can be used to evaluate the bowel, pancreas and other intra-abdominal organs.
Treatment
- How is acute diarrhea treated?
It is important to drink fluids with sugar and salt to avoid dehydration. Hydrating with drinks that contain salt and sugar will help your intestine to absorb fluids better than with water alone. Examples include oral rehydration solutions, packets, or tablets. Milk and dairy products should be avoided for 24 to 48 hours as they can make diarrhea worse.
Anti-diarrheal medications can be helpful to control severe diarrhea, including bismuth subsalicylate and medications such as loperamide, which slow motility in the GI tract. These medications should be avoided in people with high fever or bloody diarrhea because they can worsen severe colon infections. You should discuss with your healthcare provider before taking these medications if you are having bloody diarrhea or fevers.
Some infections may be treated with antibiotics. Antibiotics would only be prescribed after testing is done to understand the cause of diarrhea.
- How is chronic diarrhea treated?
Treatment will depend on the cause of the diarrhea. Medications may be provided for symptom relief while finding the cause of diarrhea, or if a treatable cause cannot be identified. Vitamin and mineral level should be checked, replacing any deficiencies, especially calcium, potassium, magnesium and zinc.
Author(s) and Publication Date(s)
Blanca Ochoa, MD and Christina M. Surawicz, MD, MACG, University of Washington School of Medicine, Seattle, WA – Published October 2002, Updated April 2007, Updated December 2012.
Katherine Falloon, MD, Cleveland Clinic Foundation, and Ann Flynn, MD, FACG, University of Utah School of Medicine – Updated October 2025.