Acute and persistent diarrhea may have causes that are different from those of chronic diarrhea. In many cases, doctors do not find the cause of diarrhea. Most diarrhea goes away on its own within 4 days, and finding the cause is not necessary.
Acute and persistent diarrhea
The most common causes of acute and persistent diarrhea are infections, travelers’ diarrhea, and side effects of medicines.
Infections
Three types of infections that cause diarrhea include
Viral infections. Many viruses cause diarrhea, including norovirus and rotavirus . Viral gastroenteritis is a common cause of acute diarrhea.
Bacterial infections. Several types of bacteria can enter your body through contaminated food or water and cause diarrhea. Common bacteria that cause diarrhea include Campylobacter , Escherichia coli (E. coli), Salmonella , and Shigella .
- Parasitic infections. Parasites can enter your body through food or water and settle in your digestive tract. Parasites that cause diarrhea include Cryptosporidium enteritis , Entamoeba histolytica , and Giardia lamblia .
Infections in the digestive tract that spread through foods or drinks are called foodborne illnesses.
Infections lasting more than 2 weeks and less than 4 weeks can cause persistent diarrhea.
Travelers’ diarrhea
Travelers’ diarrhea is caused by eating food or drinking water contaminated with bacteria, viruses, or parasites. Travelers’ diarrhea is most often acute. However, some parasites cause diarrhea that lasts longer. Travelers’ diarrhea can be a problem for people traveling to developing countries.
Side effects of medicines
Many medicines may cause diarrhea. Medicines that may cause diarrhea include antibiotics , antacids containing magnesium, and medicines used to treat cancer.
Chronic diarrhea
Some infections, food allergies and intolerances, digestive tract problems, abdominal surgery, and long-term use of medicines can cause chronic diarrhea.
Infections
Some infections from bacteria and parasites that cause diarrhea do not go away quickly without treatment. Also, after an infection, people may have problems digesting carbohydrates such as lactose or proteins in foods such as cow’s milk, milk products, or soy . Problems digesting carbohydrates or proteins can prolong diarrhea.
Food allergies and intolerances
Allergies to foods such as cow’s milk, soy, cereal grains, eggs, and seafood may cause chronic diarrhea.
Lactose intolerance is a common condition that may cause diarrhea after eating foods or drinking liquids that contain milk or milk products.
Fructose intolerance is a condition that may cause diarrhea after eating foods or drinking liquids that contain fructose, a sugar found in fruits, fruit juices, and honey. Fructose is added to many foods and soft drinks as a sweetener called high-fructose corn syrup.
Sugar alcohols such as sorbitol, mannitol, and xylitol may cause diarrhea in some people. Sugar-free candies and gum often include these sugar alcohols.
Digestive tract problems
Digestive tract problems that may cause chronic diarrhea include
- celiac disease
- Crohn’s disease
- irritable bowel syndrome and other functional gastrointestinal (GI) disorders
- small intestinal bacterial overgrowth
- ulcerative colitis
Abdominal surgery
You may develop chronic diarrhea after abdominal surgery. Abdominal surgery is an operation on the appendix, gallbladder, large intestine, liver, pancreas, small intestine, spleen, or stomach.
Long-term use of medicines
Medicines that must be taken for a long time may cause chronic diarrhea. Some medicines, such as antibiotics, can change the normal gut flora and increase your chances of infection with Clostridium difficile, a bacterium that can cause chronic diarrhea.