Roseola infantum caused by human herpesvirus-6: report of 7 cases with emphasis on complications.

Roseola infantum is not an uncommon disease in children. The etiology was not known until 1988 when Yamanishi et al in Japan first demonstrated that human herpesvirus-6 (HHV-6) was the causative agent. In the fall of 1989, we began to study the role of HHV-6 in roseola infantum in Taiwan. A total of 7 cases of suspected roseola infantum were studied and all were proven to have primary HHV-6 infections. Six were classic cases of roseola infantum, while one had only fever without the rash. Two cases developed complications; one had leukopenia and thrombocytopenia and the other had aseptic meningitis and mononucleosis. This is the first report to substantiate that HHV-6 is an important cause of roseola infantum in Taiwan, and that the virus could cause meningitis and thrombocytopenia.