• Dietary causes
  • Sorbitol, Fructose
  • Intolerance to specific foods (beans, fruit, peppers, etc.)
• Infectious causes
  • Bacterial (Salmonella, Shigella, Campylobacter, Yersinia, Plesiomonas, Aeromonas, Escherichia coli)
  • Viral (rotavirus, Norwalk agent, adenovirus)
• Medication
  • Antibiotics
  • Laxatives: Magnesium-containing

• Allergic/autoimmune
  • Milk/soy protein allergy
  • Eosinophilic enteritis
  • AIDS
  • IgA deficiency
  • Combined immunodeficiency
• Anatomic abnormalities
  • Short intestine
  • Malrotation
• Bile salt malabsorption
• Celiac disease
• Congenital causes
  • Villous atrophy
  • Holovisceral myopathy
• Encopresis
• Endocrine disorders
  • Hyperthyroidism
  • Diabetes
  • Congenital adrenal hyperplasia
• Hirschsprung enterocolitis
• Infectious causes
  • Bacterial (see Acute Diarrhea)
  • Viral (see Acute Diarrhea)
  • Parasites (Giardia, Entamoeba, Cryptosporidium)
  • Clostridium difficile
  • Bacterial overgrowth
• Inflammatory bowel disease
  • Ulcerative colitis
  • Crohn disease
• Intestinal lymphangiectasia: primary and secondary
• Irritable bowel syndrome
• Lactose intolerance (primary, secondary, congenital)
• Medication (see Acute Diarrhea)
• Necrotizing enterocolitis
• Pancreatic dysfunction
  • Cystic fibrosis
  • Shwachman syndrome
  • Chronic pancreatitis
• Post-infectious diarrhea
• Pseudo-obstruction
• Secretory tumors (VIPoma, somatostatinoma, gastrinoma)
• Vasculitis
  • Hemolytic uremic syndrome
  • Henoch-Schöenlein purpura

Question: Has the diarrhea lasted less than 2 weeks?
Significance: A distinction should be made between acute and chronic diarrhea. The cause of acute diarrhea is almost always related to an infection, a medication, or the addition of a new food.

Question: Travel history?
Significance: Questions should be asked regarding travel to areas where drinking water is contaminated (e.g., Mexico—Entamoeba) or the ingestion of infected meat (E. coli) or fresh water (well water) infected with Giardia.

Question: Is the child an adolescent who is concerned about their weight?
Significance: Laxative abuse causing an osmotic diarrhea is common among adolescents who have an eating disorder.

Question: Does the patient have other systemic symptoms?
Significance: Systemic symptoms such as fever, gastrointestinal bleeding, rash, or vomiting should be ascertained. Specific infections and inflammatory bowel disease have associated systemic symptoms.

Question: Hematochezia?
Significance: The occurrence of acute, bloody stools and fever generally indicates a bacterial infection or amebiasis; however, these same symptoms coupled with thrombocytopenia, anemia, and azotemia; or a purpuric rash can indicate hemolytic uremic syndrome or Henoch-Schöenlein purpura (HSP), respectively. Chronic bloody diarrhea, abdominal pain and weight loss are characteristic of inflammatory bowel disease.

Question: What is the age of the child?
Significance: The age of the child is important because a number of diseases present between birth and 3 months of life including congenital villus/transport abnormalities, cystic fibrosis, or milk/soy allergy. In a previously well infant who had a recent viral illness with subsequent protracted diarrhea, the diagnosis of postviral enteritis should be suspected. This disorder is characterized by severe mucosal injury resulting in disaccharidase deficiency and prolonged malabsorption. Chronic non-specific diarrhea should be considered in otherwise normal preschool-aged children who have 2 to 10 watery stools/day without other symptoms and/or etiology. Lactose intolerance commonly occurs in many older children and adults, with over a 95% occurrence rate in some ethnic groups.

Question: Chronic diarrhea with weight loss?
Significance: Inflammatory or immunologic disorders such as ulcerative colitis, Crohn disease, and celiac disease must be considered in older children with chronic diarrhea.

Finding: What are the child’s growth parameters?
Significance: An important part of the physical examination is height, weight, head circumference, and height/weight measurements. Previous measurements are necessary to make an accurate evaluation. Findings of a chronically malnourished child with years of unsuspected weight loss or poor growth velocity would indicate a divergent differential diagnosis from that of a healthy-appearing child with normal growth.

Finding: Does the child have arthritis?
Significance: Arthritis and diarrhea can occur in diseases such as inflammatory bowel disease, celiac disease, HSP, and in specific bacterial infections.

Finding: Is there nailbed clubbing?
Significance: Cystic fibrosis

Finding: Is there a right lower quadrant mass?
Significance: A right lower quadrant mass could suggest an abscess (Crohn disease, appendiceal abscess)

Test: Stool culture
Significance: Stool examination not only for blood/mucous/inflammatory cells but also for microorganisms is important in determining the etiology of the diarrhea. Stool cultures for parasites (Giardia, Entamoeba), bacterial pathogens (Salmonella, Campylobacter, Shigella, Yersinia, Aeromonas, Plesiomonas) and Clostridium difficile toxin should be obtained in all children with unexplained diarrhea.

Test: Stool gram stain
Significance: Useful in determining the presence of polymorphonuclear leukocytes suggesting a colitis.

Test: Stool pH
Significance: Useful in identifying carbohydrate malabsorption; normal stool pH is 5 to 6.

Test: Hemoccult
Significance: Documents blood

Test: 72-hour quantitative fecal fat evaluation
Significance: A sensitive test for steatorrhea. Patients need to be placed on a high-fat diet (3 g/kg) for 3 days. During this time, all stools are collected and frozen, and on completion, the amount of ingested fat is compared to excreted fat. When malabsorption is present, disorders of pancreatic function (cystic fibrosis, Shwachman syndrome) or severe intestinal disease should be suspected.

Test: Lactose breath test
Significance: A non-invasive test that measures hydrogen levels in expired air and is based on the principle that hydrogen gas is produced by colonic bacterial fermentation of malabsorbed carbohydrates. When abnormal in older healthy-appearing children, primary lactose deficiency is suggested. However, in young children, secondary lactase deficiency should be considered and small-bowel disease should be suspected.

Test: D-xylose test
Significance: Based on the principle that D-xylose absorption occurs independently of bile salts, pancreatic secretions, and intestinal disaccharidases. A specific dose of D-xylose (14.5 mg/m², maximum 25 g) is given orally after an 8 hour fast and the serum level of D-xylose is determined after 1 hour. Typically, disorders that alter or disrupt the intestinal mucosa produce abnormal results.

Test: Endoscopy and colonoscopy
Significance: These procedures have become extremely useful tests. These diagnostic tests not only allow direct visualization of the intestinal mucosa but also provide access for intestinal culture, disaccharidase and pancreatic enzyme evaluation, and intestinal biopsy.

Diarrhea can always lead to dehydration. Any child suspected of clinical dehydration should be closely observed. If oral rehydration is ineffective intravenous therapy is indicated. In addition, rarely acute right lower abdominal pain with diarrhea may indicate appendicitis. Culture negative gastrointestinal bleeding associated with severe abdominal pain and diarrhea should always be treated urgently.

Because the occurrence of diarrhea in children is quite common, the decision to pursue an evaluation rests with the primary care physician. Children who present with growth failure, non-infectious heme-positive diarrhea, or unexplained chronic diarrhea should be considered for referral to a pediatric gastroenterologist.

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Arnold L. Acute diarrhea. In: Schwartz MW, Curry TA, Sargent AJ, Blum NJ, Fein JA, eds. Principles and practice of clinical pediatrics. Chicago: Year Book, 1997:227–231.

Baldassano RN, Liacouras CA. Chronic diarrhea: a practical approach for the pediatrician. Pediatr Clin North Am 1991;38:667–685.

Rhoads JM, Powell DW. Diarrhea. In: Walker WA, Durie PR, Hamilton JR, Walker-Smith JA, Watkins JB, eds. Pediatric gastrointestinal disease. Philadelphia: BC Decker, 1990:62–78.

Vanderhoof JA. Diarrhea. In: Wyllie R, Hyams JS, eds. Pediatric gastrointestinal disease. Philadelphia: WB Saunders, 1993:187–197.