Infectious gastroenteritis: This is the most common cause of persistent diarrhea in children, often caused by viral infections such as rotavirus, norovirus, or bacterial infections like E. coli, and less commonly by parasites.

Lactose intolerance: After an episode of gastroenteritis, some children may develop transient lactose intolerance, leading to persistent diarrhea.
Toddler's diarrhea: A common condition in toddlers characterized by chronic, non-bloody diarrhea, often related to a diet high in fruit juices or sorbitol-containing foods.
Food allergy or intolerance: Allergies to foods like milk, eggs, or wheat, or intolerances to certain food components, can cause persistent diarrhea in children.
Giardiasis: An intestinal infection caused by the parasite Giardia lamblia, which can lead to chronic diarrhea in children.

Inflammatory bowel disease (IBD): Conditions like Crohn's disease and ulcerative colitis can present with chronic diarrhea and must be considered to avoid delayed diagnosis and potential complications.
Celiac disease: An autoimmune reaction to gluten that can cause chronic diarrhea, malabsorption, and failure to thrive if not recognized and treated.
Chronic infections: Such as persistent bacterial, parasitic, or viral infections that may require specific treatment to resolve.

Congenital intestinal disorders: Conditions like congenital chloride diarrhea or congenital sodium diarrhea, which are rare but can cause severe, persistent diarrhea from birth.
Immunodeficiency disorders: Certain immunodeficiencies can predispose children to chronic or recurrent infections, including those causing diarrhea.
Tumors or structural abnormalities: Though rare, tumors or structural abnormalities of the gastrointestinal tract can cause chronic diarrhea in children.