Some Causes and Features of Diarrhea
Cause | Common Features* | Tests† |
|---|---|---|
Acute (less than 1 week)‡ | ||
Gastroenteritis due to viruses, bacteria, or parasites‡ | Often vomiting Rarely fever or blood in stool Little or no abdominal pain (except during vomiting) Sometimes recent contact with infected people (such as those at a day care center, at a camp, or on a cruise), with animals at a petting zoo (where Escherichia [E.] coli may be acquired), or with reptiles (where Salmonella bacteria may be acquired) Sometimes recent consumption of undercooked, contaminated food or contaminated water | A doctor’s examination Sometimes examination and testing of stool |
Diarrhea that started suddenly, often with vomiting, within 4 to 8 hours of eating contaminated food Often present in other people Typically lasting 12 to 24 hours | A doctor’s examination alone | |
Recent use of a drug that causes diarrhea Often no other symptoms | A doctor’s examination Sometimes tests for Clostridioides difficile (formerly Clostridium difficile) toxin in stool | |
Chronic (4 weeks or more) | ||
Dietary factors such as
| Diarrhea only after consuming a substance that could cause diarrhea Abdominal bloating and passing of gas (flatulence) Explosive diarrhea | A doctor’s examination Sometimes a breath test to detect hydrogen, indicating undigested food Examination and analysis of stool to check for unabsorbed carbohydrates |
Intermittent diarrhea associated with abdominal pain Often diarrhea alternating with constipation No bleeding, weight loss, or fever Usually begins during the teens or 20s Symptoms usually present for more than 12 weeks Changes in the frequency of bowel movements or consistency of stool | A doctor’s examination Sometimes blood tests and colonoscopy | |
Inflammatory bowel disease such as | Blood in stool, crampy abdominal pain, weight loss, and loss of appetite Sometimes arthritis, rashes, sores in the mouth, and tears in the rectum | Colonoscopy CT or MRI Stool tests |
Malabsorption disorders such as
| Light-colored, soft, bulky, and unusually foul-smelling stool that may appear oily Abdominal bloating and flatulence Weight loss For tropical sprue, long-term (over 1 month) residence in a tropical country For pancreatic insufficiency, usually in a person known to have a disorder of the pancreas (such as chronic pancreatitis or cystic fibrosis) | Tests to measure the amount of fat in stool samples collected over several days If celiac disease is suspected, blood tests to measure the antibodies produced when people with celiac disease eat foods containing gluten For celiac disease and tropical sprue, especially celiac disease, biopsy of the small intestine |
Certain tumors
| For colon cancer, sometimes blood in stool, decreased stool diameter, and weight loss For endocrine tumors, various symptoms, including abdominal pain or cramping, flushing, and massive watery diarrhea | Blood tests Colonoscopy |
Often nervousness, trouble tolerating a hot environment, fatigue, palpitations, weight loss, and rapid heart rate | Blood tests | |
Surgery on the stomach or intestines (such as gastric bypass for weight loss or removal of a significant length of intestine) | Obvious recent surgery | A doctor’s examination alone |
* Features include symptoms and the results of the doctor's examination. Features mentioned are typical but not always present. | ||
† Although a doctor's examination is always done, it is mentioned in this column only if the diagnosis can sometimes be made by the doctor's examination alone, without any testing. | ||
‡ Diarrhea that has been present for 1 to 4 weeks may be a lingering case of acute diarrhea or the early stage of a disorder that causes chronic diarrhea. | ||
§ Certain infections and certain drugs can also cause chronic diarrhea. | ||
CT = computed tomography; HIV = human immunodeficiency virus; MRI = magnetic resonance imaging. | ||