The role of human herpesvirus 6, human herpesvirus 7, Epstein-Barr virus and cytomegalovirus in the aetiology of pityriasis rosea.

AIM: To identify the role of human herpesvirus 6 (HHV-6), HHV-7, Epstein-Barr virus (EBV) and cytomegalovirus (CMV) in the pathogenesis of pityriasis rosea (PR).

MATERIAL: Polymerase chain reaction with specific primers for HHV-6 and HHV-7 DNA sequences was performed on the blood and tissue samples of 25 patients with PR and on the blood samples of age- and sex-matched healthy controls. HHV-6, EBV, CMV immunoglobulin M (IgM) and IgG were analysed by enzyme-linked immunosorbent assay, HHV-7 IgM and IgG were analysed by indirect immunofluorescence on the serum samples of the study population. In the patient group, the values were studied 2 weeks later again (second control).

RESULTS: There were no differences between the first and second controls of the patients and healthy subjects regarding HHV-6 IgM, HHV-7 IgM, CMV IgM, EBV IgM results. There were significant differences between the first [HHV-6 DNA (2 of 25), HHV-7 DNA (6 of 25)] and second control [HHV-6 DNA (1 of 25), HHV-7 DNA (11 of 25)] of the patients for the blood samples in favour of HHV-7. PR patients showed higher amounts of HHV-6 and HHV-7 DNA positivity when compared with that of healthy subjects. HHV-7 seemed to be more important regarding tissue samples [HHV-6 DNA (7 of 25), HHV-7 DNA (12 of 25) first control, HHV-6 DNA (6 of 25), HHV-7 DNA (12 of 25) second control] as well as blood samples.

CONCLUSION: Though our results failed to support a causal relationship among EBV, CMV and PR, they indicated a possible role for HHV-6 and especially HHV-7 in a group of Turkish patients but other aetiological factors may exist.