Association of pityriasis rosea with human herpesvirus-6 and human herpesvirus-7 in Taipei

Background and purpose: Pityriasis rosea (PR) is a common papulosquamous skin disease with unknown etiology. The possible relationship of PR with human herpesvirus infection (HHV) has been extensively studied. This study used the polymerase chain reaction (PCR) to investigate the presence of human herpesvirus 6 and 7 (HHV-6 and HHV-7) in 41 PR patients from two hospitals in Northern Taiwan. The epidemiologic features of PR in patients were also studied. Methods: A total of 41 PR patients (11 males, 30 females) were enrolled in this study from April 1999 to March 2000. PCR of skin biopsy specimens from 24 PR patients was used to identify the existence of HHV-6 and HHV-7. Viral culture from PR biopsy specimens was also performed. Blood from these patients was sampled for Venereal Disease Research Laboratory tests. Skin biopsies from 20 age- and sex-matched controls with other skin diseases were also subjected to PCR study. Results: The ages of the 41 PR patients ranged from 8 to 62 years. An increased incidence (17/41) of PR episodes was observed during the spring. Both HHV-6 and HHV-7 DNA was below the limit of detection in all biopsy specimens from patients and healthy controls. Viral culture for HHV was negative in all patients. Conclusion: The epidemiologic features of PR in this series are comparable to other studies except for an exaggerated female predominance (male:female ratio 1:2.7). Our data indicate a lack of association between HHV-6 and HHV-7 infection and PR.