Diagnosis of fatty liver in children should occur in parallel to investigation for other causes of liver disease

Fatty liver is the most common chronic liver disease in European children. Historically, non-alcoholic fatty liver disease (NAFLD) evolved as a diagnosis of exclusion, in which the presence of hepatic steatosis (with or without inflammation and fibrosis) in the absence of an alternative cause (particularly alcohol) led to the diagnosis of NAFLD. Hepatic steatosis has long been recognised as a manifestation of a wide array of conditions, ranging from viral hepatitis, autoimmune liver disease, Wilson's disease, α1-antitrypsin deficiency, and rarer metabolic disorders.