Diarrhea is frequent, loose, or watery bowel movements (BMs) that differ from a child’s normal pattern. It is a very common problem in children.
Identifying mild diarrhea may be difficult because in healthy children, the number and consistency of BMs vary with age and diet. For example, breastfed infants who are not yet receiving solid food often have frequent, loose stools that are considered normal. A sudden increase in number and looseness may indicate diarrhea in these infants. However, having watery stools for more than 24 hours is never normal.
Sometimes diarrhea contains blood or mucus. Children with diarrhea may lose their appetite, vomit, lose weight, or have a fever. If diarrhea is severe or lasts a long time, children are likely to lose a significant amount of body fluid (dehydration). Infants and young children can become dehydrated more quickly, sometimes in less than 1 day. Severe dehydration can cause seizures, brain damage, and death.
Worldwide, diarrhea causes 1.2 million deaths a year. In the United States, diarrhea accounts for approximately 9% of hospitalizations for children under 5 years old.
(See also Diarrhea in adults.)
Causes of Diarrhea in Children
Likely causes of diarrhea depend on whether it lasts less than 2 weeks (acute) or more than 2 weeks (chronic). Most cases of diarrhea are acute.
Common causes
Acute diarrhea is usually caused by
Infectious gastroenteritis
Use of antibiotics
Gastroenteritis is usually caused by a virus, but it can be caused by bacteria or a parasite.
Food poisoning usually refers to diarrhea, vomiting, or both caused by eating food contaminated by toxins produced by certain bacteria, such as staphylococci or clostridia.
Certain antibiotics can alter the types and number of bacteria in the intestine. As a result, diarrhea can occur. Sometimes using antibiotics enables a particularly dangerous bacteria, Clostridioides difficile (C. diff), to multiply. Clostridioides difficile releases toxins that can cause inflammation of the lining of the large intestine (colitis).
Chronic diarrhea is usually caused by
Dietary factors, such as lactose intolerance or overconsumption of certain foods
Infections (particularly those caused by parasites)
Less common causes
Acute diarrhea can also result from more serious disorders such as appendicitis, intussusception, and hemolytic-uremic syndrome (a complication of certain types of bacterial infection). These serious disorders are usually associated with other worrisome symptoms besides diarrhea, such as severe abdominal pain or swelling, bloody stools, fever, and ill appearance.
Chronic diarrhea can also result from disorders that interfere with the absorption of food (malabsorption disorders), such as cystic fibrosis, and a weakened immune system (due to a disorder such as HIV infection or use of certain medications).
Diarrhea sometimes results from constipation. When hardened stool accumulates in the rectum, soft stool may leak around it and into the child's underwear.
Evaluation of Diarrhea in Children
Warning signs
Certain symptoms are cause for concern. They include
Signs of dehydration, such as decreased urination, lethargy or listlessness, crying without tears, extreme thirst, and a dry mouth, and weight loss
Ill appearance
High fever
Blood in stool
Pain in the abdomen and, when touched, extreme tenderness
Bleeding in the skin (seen as tiny reddish purple dots [petechiae] or splotches [purpura])
When to see a doctor
Children with any warning signs should be evaluated by a doctor right away, as should those who have diarrhea and are not drinking or are drinking very little.
If children have no warning signs and are drinking and urinating normally, the doctor should be called if diarrhea lasts 2 days or more or if there are more than 6 to 8 episodes of diarrhea a day. If diarrhea is mild, a doctor’s visit is generally unnecessary. Children with prolonged diarrhea should be seen by a doctor.
What the doctor does
Doctors first ask questions about symptoms and medical history. Doctors then do a physical examination. What they find during the history and physical examination often suggests a cause and the tests that may need to be done (see table Some Causes and Features of Diarrhea in Children).
Doctors ask what the BMs look like, how frequent they are, how long they last, and whether the child has other symptoms, such as fever, vomiting, or abdominal pain.
Doctors also ask about potential causes, such as diet, use of antibiotics, consumption of possibly contaminated food, recent contact with animals, and recent travel.
A physical examination is done, looking for symptoms of dehydration and disorders that can cause diarrhea. The abdomen is checked for swelling and tenderness. Doctors also evaluate the child's growth.
Some Causes and Features of Diarrhea in Children
Cause | Common Features* | Tests |
|---|---|---|
Acute diarrhea (lasting less than 2 weeks) | ||
Antibiotic use | Recent use of antibiotics Often no other symptoms | A doctor’s examination Sometimes tests for Clostridioides difficile toxin in stool |
Gastroenteritis due to viruses, bacteria, or parasites† | Often with vomiting Dehydration common especially among infants and young children Sometimes fever and abdominal pain Rarely blood in stool 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 (which may be infected with Salmonella bacteria) or recent consumption of undercooked, contaminated food or contaminated water | A doctor’s examination Sometimes examination and testing of stool |
Food allergy: Hives, rash, swelling of the lips, vomiting, diarrhea, and difficulty breathing within minutes to several hours after eating Often an already identified food allergy Food poisoning: Nausea, vomiting, abdominal pain, and diarrhea several hours after eating contaminated food | A doctor’s examination | |
Abdominal pain, vomiting, and usually bloody diarrhea for a few days, followed by development of pale skin and decreased urination Sometimes bleeding in the skin (seen as tiny reddish purple dots or splotches) | Blood tests Examination and testing of stool | |
Chronic diarrhea (lasting 2 weeks or more) | ||
Vomiting Poor feeding Weight loss, poor growth, or both Blood in stools | Stool tests Symptoms that lessen when the formula is changed Possibly endoscopy, colonoscopy, or both | |
Excessive consumption of fruit juices (especially apple, pear, and prune) | Drinking more than 4–6 ounces (120–180 milliliters) of fruit juice a day Often no other symptoms except diarrhea | A doctor’s examination Resolution of diarrhea after decreasing consumption of fruit juices |
Inflammatory bowel disease such as | Blood in stool, crampy abdominal pain, weight loss, loss of appetite, and poor growth Sometimes arthritis, rashes, sores in the mouth, and tears in the rectum | Colonoscopy Sometimes CT or x-rays after barium is inserted in the rectum (barium enema) |
Lactose intolerance (inability to digest lactose, the sugar in milk and dairy products) | Abdominal bloating, passing of gas (flatulence), and explosive diarrhea Diarrhea after consumption of milk and dairy products | A doctor’s examination Sometimes a breath test to detect hydrogen (indicates undigested carbohydrates) Examination and analysis of stool to check for unabsorbed carbohydrates |
Malabsorption disorders such as | Light-colored, soft, bulky, and unusually foul-smelling stool that may appear oily Abdominal bloating and flatulence Poor weight gain With cystic fibrosis, frequent respiratory infections With acrodermatitis enteropathica, rash and cracks in the corners of the mouth | Examination and testing of stool If celiac disease is suspected, blood tests to measure antibodies against gluten (a protein in wheat) and biopsy of the small intestine If cystic fibrosis is suspected, a sweat test and possibly genetic testing If acrodermatitis enteropathica is suspected, a blood test for zinc deficiency |
A weakened immune system due to
| Frequent infections Weight loss or poor weight gain Sometimes an already identified HIV infection | Blood tests for HIV A complete blood cell count and other blood tests to evaluate the immune system |
* Features include symptoms and results of the doctor's examination. Features mentioned are typical but not always present. | ||
† Infections by bacteria, parasites, or viruses can also cause chronic diarrhea. | ||
CT = computed tomography; HIV = human immunodeficiency virus. | ||
Testing
If diarrhea lasts less than 2 weeks and warning signs are not present, the cause is probably gastroenteritis due to a virus, and testing is usually unnecessary. However, if doctors suspect another cause, tests are done to check for it.
Tests are typically done when children have warning signs. If they have signs of dehydration, blood tests are done to measure levels of electrolytes (sodium, potassium, calcium, and other minerals necessary to maintain the fluid balance in the body). If other warning signs are present, tests may include a complete blood cell count, urine tests, examination and analysis of stool, abdominal x-rays, or a combination.
Treatment of Diarrhea in Children
Specific causes of diarrhea are treated. For example, if children have celiac disease, gluten is removed from their diet. Antibiotics that cause diarrhea are stopped or changed if a doctor recommends it. Gastroenteritis due to a virus usually disappears without treatment.
Medications to stop diarrhea, such as loperamide, are not recommended for infants and young children.Medications to stop diarrhea, such as loperamide, are not recommended for infants and young children.
Dehydration
Because the main concern in children is dehydration, treatment is focused on rehydrating by giving fluids and electrolytes (see Treatment of Dehydration in Children). Most children with diarrhea are successfully treated with fluids given by mouth (orally). Fluids are given by vein (intravenously) only if children are not drinking, are vomiting a lot, or are severely dehydrated. Oral rehydration solutions that contain the right balance of carbohydrates and sodium are used. These solutions are widely available in the United States and many other countries without a prescription and can be purchased at pharmacies and supermarkets. Sports drinks, sodas, juices, and similar drinks have too little sodium and too much carbohydrate and should not be used.
If children are also vomiting, small, frequent amounts of fluid are given at first. Typically, 1 teaspoon (5 milliliters) is given every 5 minutes. If children keep down this amount, the amount is gradually increased. If the child is not vomiting, the initial amount of fluid does not need to be limited. With patience and encouragement, most children can take enough fluid by mouth to avoid the need for intravenous fluid. However, children with severe dehydration may need intravenous fluids.
Diet
As soon as children have received sufficient fluids and are not vomiting, they should be given an age-appropriate diet. Infants may resume breast milk or formula.
In children with chronic diarrhea, the treatment depends on the cause, but providing and maintaining adequate nutrition and monitoring for possible vitamin or mineral deficiencies are most important.
Key Points
Diarrhea is common among children.
Gastroenteritis, usually due to a virus, is the most common cause.
Children should be evaluated by a doctor if they have any warning signs (such as signs of dehydration, severe abdominal pain, fever, or blood or pus in stool).
Testing is rarely necessary when diarrhea lasts less than 2 weeks.
Dehydration is likely if diarrhea is severe or lasts a long time.
Giving fluids by mouth effectively treats dehydration in most children.
Medications to stop diarrhea, such as loperamide, are not recommended for infants and young children.
