Prolonged Viremia and Immune Response to Human Herpesvirus 7 in an Infant With Liver Dysfunction

Abstract

Human herpesvirus 7 (HHV-7) is the second newest virus in the human herpesvirus group. HHV-7 is closely related to human herpesvirus 6 (HHV-6) in both virologic and clinical aspects. Both viruses are now known to cause so-called exanthem subitum with or without complications.1,2 The reported complications associated with HHV-6 infection are hepatitis,3 febrile convulsion,4 encephalitis,5 acute hemiplegia,6 invagination,7 hemophagocytic syndrome,8 and idiopathic thrombocytopenic purpura.9 There are two cases of acute hemiplegia as a complication of exanthem subitum caused by HHV-7.10 In only one case report was HHV-7 infection the probable cause of hepatitis.11 This report describes an infant who had exanthem subitum complicated by liver dysfunction. Because a prolonged viremic phase was observed, the cellular immunities to HHV-6 and HHV-7 were examined. A previously healthy 11-month-old girl visited the outpatient clinic at Shingu Municipal Hospital. Although her general condition was good, she had experienced fever of up to 39°C for 5 days. Acetaminophen was given to her up to twice a day while she was febrile. When she visited the clinic, her temperature was 38.2°C. She had mild diarrhea and otitis media. A salmon–pink colored macular rash was scattered mainly on the lower part of the trunk. There was no hepatosplenomegaly. Her throat was inflamed, and several lymph nodes 5 mm in diameter were palpable on the neck and inguinal area. The next day, her fever subsided and she looked fine. The macular skin rash had increased on the lower part of the trunk but disappeared in 3 days. The clinical diagnosis was exanthem subitum complicated by liver dysfunction. The liver dysfunction normalized within 1 month after the onset of the disease. She had been healthy since she became afebrile. Laboratory findings on day 5 of the illness …