Functional dyspepsia: This is a common cause of epigastric pain in children, characterized by recurrent pain in the upper abdomen that is not associated with any underlying organic cause. It is often related to eating or can occur when the stomach is empty.

Gastroesophageal reflux disease (GERD): GERD can cause epigastric pain due to the reflux of stomach acid into the esophagus, leading to inflammation and discomfort.
Peptic ulcer disease: Although less common in children, peptic ulcers can cause epigastric pain, especially if related to Helicobacter pylori infection or the use of nonsteroidal anti-inflammatory drugs (NSAIDs).
Constipation: Constipation is a common issue in children and can sometimes present with abdominal pain that may be perceived as epigastric.
Viral gastroenteritis: Infections of the stomach and intestines can cause epigastric pain, along with other symptoms like nausea, vomiting, and diarrhea.

Appendicitis: Although appendicitis typically presents with pain in the lower right abdomen, it can initially cause more generalized or upper abdominal pain, including epigastric pain, especially in early stages or in younger children.
Pyloric stenosis: This condition, characterized by the narrowing of the pylorus (the passage between the stomach and small intestine), can cause severe vomiting and epigastric pain, particularly in infants but can occasionally be seen in older children.
Intussusception: A condition where a part of the intestine slides into an adjacent part, which can cause severe abdominal pain, including epigastric pain, along with vomiting and bloody stools.
Pancreatitis: Inflammation of the pancreas can cause severe epigastric pain radiating to the back, and while rare in children, it can be associated with trauma, certain medications, or genetic conditions.

Inflammatory bowel disease (IBD): Conditions like Crohn's disease and ulcerative colitis can cause chronic abdominal pain, including epigastric pain, along with diarrhea, weight loss, and other symptoms.
Gastric volvulus: A rare condition where the stomach twists abnormally, which can cause severe epigastric pain and vomiting.
Hernias: Hiatal hernias or other abdominal wall hernias can cause epigastric pain, especially if they become incarcerated or strangulated.
Malignancies: Although extremely rare in children, abdominal tumors can cause epigastric pain among other symptoms, and include conditions like neuroblastoma or lymphoma.