Hyperleukocytosis in a premature infant with intrauterine herpes simplex encephalitis.

Herpes encephalitis is a rare but devastating infection in premature infants. We report a 29 week gestation infant with severe intrauterine cutaneous and central nervous system herpes accompanied by hyperleukocytosis. Leukemoid reactions are not uncommon in this population, but the association of herpes encephalitis and a leukemoid reaction or hyperleukocytosis has not been reported previously.