Association between Pityriasis Rosea (PR) and HHV-6/HHV-7 Infection: Importance of Sample Selection and Diagnostic Techniques.

Recent studies have focused on the role of human herpesvirus 6 (HHV-6) and human herpesvirus 7 (HHV-7) in PR etiology with varying results. In our study, with the approach that the discrepancy between the results may be related to the different samples and techniques used, we aimed to clarify the etiology by examining tissue and plasma samples using molecular methods and evaluating the results together with serological parameters. Skin biopsies and plasma samples of twenty-five PR patients were tested to detect HHV-6 and HHV-7 DNA using calibrated quantitative real-time polymerase chain reaction (CQ RT-PCR). IgG and IgM antibodies against HHV-6 and HHV-7 were tested by enzyme-linked immunosorbent assay and indirect immunofluorescence. Of the patient group, 64% were positive for HHV-6 IgG without IgM positivity. HHV-6 DNA was present in seven tissue and ten plasma samples. HHV-7 positivity was 100% and 12% for IgG and IgM antibodies, respectively. HHV-7 DNA was detected in four tissue samples and one plasma sample. Patients with HHV-7 DNA-positive plasma and tissue samples had also HHV-7 IgM antibodies. In conclusion, our results seem to support the role of HHV-6/HHV-7 in the etiology of PR. To clarify the etiology of PR and avoid confusion, the collection of different biological materials simultaneously and the usage of CQ RT-PCR as a diagnostic technique are recommended.