Hypoglycemia in People Who Do Not Have Diabetes: Conditions Occurring in Infancy and Childhood

Children rarely develop hypoglycemia. If they do, causes may include

• Brief intolerance to fasting, often in conjunction with an illness that disturbs regular eating patterns. Children usually outgrow this tendency by age 10.
• Hyperinsulinism, which is the excessive production of insulin. This condition can result in transient neonatal hypoglycemia, which is common in infants of mothers with diabetes. Persistent hyperinsulinism in infants or children is a complex disorder that requires prompt evaluation and treatment by a specialist.
• Enzyme deficiencies that affect carbohydrate metabolism. These deficiencies can interfere with the body's ability to process natural sugars, such as fructose and galactose, glycogen, or other metabolites.
• Hormonal deficiencies such as lack of pituitary or adrenal hormones.

source: http://diabetes.niddk.nih.gov/dm/pubs/hypoglycemia/index.htm