HHV-6 infection - not only tertian fever.
The primary infection with the human herpesvirus (HHV) 6 usually occurs before the age of two (95%) and clinically either presents as tertian fever followed by exanthem subitum (10%) or even more often as febrile disease without an exanthem. In adults an active HHV-6 infection can present as febrile illness. A 19-year-old immunocompetent patient presented with high fever, exanthem, swelling of the lymph nodes and pancytopenia and was serologically diagnosed as active HHV-6 infection with anti- HHV-6-IgM- and -IgG antibodies. Since the antibodies were already detectable on day 5 of disease, with persistence of high IgG and undetectable IgM after 4 weeks, a reactivation seemed most likely. There was no evidence for an underlying immunosuppressive disease or reactivation induced by viral co-infection. Fulminant hepatitis or meningoencephalitis are the most frequent complications in immunocompetent individuals and have to be recognized at an early stage.