Neonatal hepatitis is an intrahepatic disease characterized by conjugated hyperbilirubinemia. It is more likely to occur in preterm infants or infants small for their gestational age. Causes may be idiopathic, immune, genetic, metabolic, or infective. Idiopathic neonatal hepatitis is characterized by conjugated hyperbilirubinemia of a prolonged presentation not explained by genetic, metabolic, or infectious causes; it is associated with neonatal cholestasis and differentiated from biliary atresia. 

This summary focuses on viral neonatal hepatitis. Refer to the DDx & Pitfalls section for additional causes of neonatal hepatitis. 

Infectious forms include hepatitis A, hepatitis B, and hepatitis C virus infections, generally transmitted vertically from the birthing parent. These infections are rarely acquired due to blood transfusion or horizontally from medical staff. 

• Hepatitis A virus (HAV) – HAV is rare; it may be asymptomatic, or neonates may present with poor feeding, jaundice, fever, vomiting, and hepatomegaly. 
• Hepatitis B virus (HBV) – HBV-infected neonates, even while asymptomatic, are infectious and at risk for developing chronic disease, including cirrhosis and hepatocellular cancer. 
• Hepatitis C virus (HCV) – HCV is less likely to be transmitted vertically by the birthing parent or by contaminated blood. There is a slightly greater chance of transmission by an HIV-infected birthing parent. Mostly asymptomatic, infants with acquired HCV may be diagnosed by the presence of HCV antibodies. Lengthy membrane rupture and high-risk procedures such as fetal scalp monitoring increase infection risk in newborns exposed to HCV-infected birthing parents. Some of these children may develop advanced liver disease in later life. 
• Hepatitis D virus – Hepatitis D occurs only in the presence of HBV and is rarely vertically transmitted to infant. 
• Hepatitis E virus – Hepatitis E is of concern in endemic countries.

Other viral causes include neonatal cytomegalovirus infection, rubella, neonatal herpes simplex virus infection, coxsackie virus infection, and echoviral and paramyxoviral infections.

Related topic: neonatal jaundice