Diarrhea is usually caused by a stomach virus, especially if it is also associated with vomiting and low grade fever. It is important to mention any recent travel to your doctor when your child has diarrhea.
Most uncomplicated cases go away on their own without treatment, except extra fluids to prevent dehydration, and testing for the specific cause of diarrhea is usually not necessary. Antidiarrheal medications should usually be avoided in children.
Common causes of acute diarrhea, lasting less than 14 days, include:
- Acute viral gastroenteritis is a very common problem in infants and children and is usually caused by a stomach virus, such as the rotavirus. Other common viruses that can cause diarrhea include the Norwalk virus and enteric adenovirus. Symptoms include a fever, stomach ache, vomiting and watery diarrhea. Although the vomiting typically lasts only two to three days, the diarrhea can last for one to two weeks before it finally resolves. There is no cure or medicine to treat gastroenteritis, but there are many things that can be done to help your child through this illness, including giving extra fluids to prevent dehydration. A rotavirus stool enzmye immunoassay test is available, and can help to diagnose children with rotavirus, which is sometimes helpful to make sure that they do not have another cause of diarrhea.
- Inflammatory acute diarrhea is usually caused by bacteria, which can cause dysentery, with bloody stools that are mucousy, fever, cramps and abdominal pain, and a loss of appetite. Bacteria that commonly cause diarrhea include Shigella, Escherichia coli (which can be associated with hemolytic uremic syndrome), Salmonella, Campylobacter, Yersinia entercolitica, Vibrio cholera and C. difficile (most common in children who have recently been on antibiotics). Examination of the stool can help to determine if diarrhea is caused by a bacterial infection if your child has symptoms of dysentery. Commonly performed tests include an examination for white blood cells or polys, which are commonly seen in bacterial infections, and rarely seen in viral gastroenteritis. An examination for blood and a culture may also be performed. Even though caused by a bacteria, not all of these types of infections should be treated with antibiotics. Shigella infections, or shigellosis are commonly treated with antibiotics, but other infections, including salmonellosis do not improve with antibiotics and treating children with this infection can actually cause then to be contagious for longer periods of time.
- Protozoal enteric gastroenteritis are caused by parasites, another common cause of acute diarrhea. Children with these infections typically have large amounts of watery diarrhea without blood, abdominal cramping, decreased appetite and weight loss. Common parasites that cause diarrhea include Giardia lamblia, which is usually spread from contaminated water supplies, especially streams, Cryptosporidium, which is commonly found in pets and farm animals and can be spread in day care settings, and Entamoeba histolytica, most common in travelers and immigrants to the US and which can cause bloody diarrhea. Treatment is usually with antiparasitic medications, including furazolidone and metronidazole (Flagyl). Testing of stool for ova and parasites (O&P) and Giardia antigen can help detect these infections.
- Food Poisoning: Almost any food can become contaminated by a virus, bacteria, or parasite and cause food poisoning. Foods can also make you sick if they are contaminated with pesticides or other toxins. The most common symptoms of food poisoning include vomiting, diarrhea, abdominal cramps, nausea and fever and they begin a short time after eating a contaminated food. In most people symptoms are mild and clear up quickly without treatment, but food poisoning can lead to dehydration, kidney failure and even death.
- Diarrhea is also a common side effect of taking antibiotics.
Persistent or chronic diarrhea is defined as diarrhea that lasts for more than two weeks. A referral to a Pediatric Gastroenterologist is sometimes necessary to evaluate children with chronic diarrhea, especially if the initial screening examinations are normal. In addition to infections, common causes of chronic diarrhea can include conditions that interfere with digestion or absorption, and include:
- Chronic gastroenteritis can be caused by infections, including those caused by viruses, bacteria and parasites. Most children with chronic diarrhea will have a stool test for polys and blood, a routine bacterial culture, an ova and parasite test, a test for the Giardia antigen and C. difficile toxin, especially if he has recently been on antibiotics.
- Postinfectious diarrhea sometimes occurs in children with gastroenteritis and may be from an intolerance to lactose or proteins in cow's milk. Soy milk or formula (for younger children) may be helpful for children with this condition.
- Toddler's Diarrhea or chronic nonspecific diarrhea usually occurs in children between the ages of 6 months and 3 years, and causes loose, watery stools in children without other symptoms. Although they have chronic diarrhea, children with toddler's diarrhea should have a normal appetite and will be growing and developing normally, and usually drink too much juice. If your doctor suspects that you child's diarrhea is from this condition, then it may help to decrease the amount of fluids your child drinks, and especially avoid juices with a high sorbital or fructose content, like apple and pear juice. Instead, give him orange and grape juice. It may also help to increase the amount of fat and fiber in his diet.
- Malabsorption can be caused by many different medical conditions, including cystic fibrosis, short bowel syndrome, celiac disease or gluten sensitive enteropathy and infections, especially Giardiasis. Children with malabsorption typically have very large and foul smelling stools, which may appear greasy, weight loss or poor weight gain and abdominal distention. An examination for stool fat content or a 72 hour stool collection for fat analysis, a test for carbohydrate by checking for reducing substances, and testing the stool pH may be helpful to see if a child has malabsorption. Children with malabsorption may also have a low serum albumin concentration. Other testing may include a small bowel biopsy.
- irritable bowel syndrome: Children with IBS have crampy abdominal pain and bowel movements that alternate between normal, constipation and diarrhea.
- Inflammatory bowel disease, including Ulcerative Colitis and Crohn's disease, with the most common symptoms being diarrhea, usually with bleeding, cramping abdominal pain, obstruction (a blockage of the intestine), malabsorption (failure of the intestines to absorb minerals and nutrients), and weight loss or poor weight gain. Other symptoms can include fever, anorexia (poor appetite), anemia (low blood counts), skin rashes, especially erythema nodosum (tender red bumps or nodules on the front of the lower legs) and pyoderma gangrenosum (painful skin ulcers), oral aphthous ulcers, and hepatitis (inflammation of the liver). Children with Crohn disease can also have perirectal disease, with fistulas, abscesses, or fissures around the rectum.
- lactose intolerance: diarrhea, abdominal pain, bloating, gas and weight loss can occur in children who don't have enough of the enzyme lactase to digest lactose in the foods they eat. While some children do have to avoid all products with lactose, others are able to handle some foods, such as yogurt, and other foods after taking a lactase enzyme supplement. See our guide to calcium requirements to make sure that your child is getting enough calcium if he isn't able to drink milk. Soy milk is a good alternative for children with lactose intolerance.
- Other causes of chronic diarrhea can include food intolerances, immune disorders, metabolic abnormalities, hormone secreting tumors, and other conditions that affect the pancreas, liver or small intestine.
Testing for chronic diarrhea can sometimes include a barium enema or other imaging studies, ileocolonoscopy, and biopsies, especially if the child has failure to thrive.