From the Guidelines

Chronic diarrhea in toddlers is most commonly caused by infectious agents, with rotavirus being a major contributor.

Infectious agents, such as rotavirus, norovirus, and bacterial pathogens like Salmonella and Shigella, are common causes of chronic diarrhea in toddlers 1.
The risk of death from diarrhea is increased among certain groups, including African Americans, those with prematurity, low birth weight, less maternal education, and low income 1.

Rotavirus vaccine has been shown to be effective in preventing rotavirus disease and reducing the burden of acute gastroenteritis in toddlers 1.
General measures, such as hand hygiene, proper food preparation and storage, and avoidance of high-risk foods, can also help reduce the risk of infectious diarrhea 1.
Adequate fluid and electrolyte intake is essential for managing diarrheal illness and preventing dehydration 1.

Laboratory investigation is not always necessary for acute diarrhea, but may be warranted in certain cases, such as immunocompromised individuals or suspected outbreaks 1.
Antimicrobial agents should be used judiciously, as they can contribute to antimicrobial resistance and worsen illness 1.

From the Research

Chronic diarrhea in toddlers can be caused by various factors, including:
- Celiac disease and cow milk allergy, which were found to be the most common causes of chronic diarrhea in a study published in the Indian Journal of Pediatrics 2
- Malnutrition, which was detected in 80% of cases in the same study 2
- Bacterial and parasitic factors, which were found to be present in 26% of cases 2
- Postinfectious gastroenteritis, which was found to be present in 10% of cases 2
Other possible causes of chronic diarrhea in toddlers include:
- Irritable colon of infancy or protracted viral enteritis with low-grade mucosal injury, which can be treated with a high-fat, low-carbohydrate diet that includes whole milk 3
- Infections, such as parasites like giardia, cryptosporidia, and cyclospora, although these are uncommon causes of chronic diarrhea 4
- Toddler's diarrhea, which is a common condition in young children 5
- Food intolerance, such as intolerance to cow's milk protein 5

The diagnosis of chronic diarrhea in toddlers should be based on noninvasive techniques, with endoscopy decided based on clinical criteria and noninvasive tests to assess digestive absorptive functions and intestinal inflammation 5
A stepwise approach may reduce the need for endoscopy, and treatment should be directed to the underlying disease 5, 6

Treatment of chronic diarrhea in toddlers is substantially different from that in adults and includes a major role for nutritional interventions 5
Institution of a high-fat, low-carbohydrate diet that includes whole milk may result in significant improvement in some cases 3
Treatment should be directed to the underlying disease, and a thorough evaluation should detect most infections causing chronic diarrhea 4, 6