Severe leukemoid reaction in a preterm infant with congenital cytomegalovirus infection.

Leukemoid reaction, defined as a total leukocyte count of >50,000/mm, is most commonly related to antenatal administration of steroids, infections, and transient myeloproliferative disorder of Down syndrome in newborns. Atypical presentations of viral infections can be a diagnostic challenge in the newborn period. Cytomegalovirus (CMV) infection causes a multisystem disease, and symptomatic infants generally present with intrauterine growth restriction, hepatosplenomegaly, cholestasis, rash, thrombocytopenia, and microcephaly. We present a case of a preterm infant with severe myeloid leukemoid reaction (leukocyte count >100,000/mm) at birth who was diagnosed with congenital CMV infection on the basis of CMV polymerase chain reaction results after the appearance of cholestasis, blueberry muffin rash, and hepatosplenomegaly.