Pityriasis rosea is not associated with human herpesvirus 7

Objective: To examine the proposed association between pityriasis rosea and human herpesvirus 7 (HHV-7). Design: A retrospective cross-sectional survey. Setting: University medical center in Switzerland. Patients: Thirteen patients with pityriasis rosea and 14 persons with norma l skin (control subjects). Main Outcome Measures: Detection of HHV-7-specific DNA sequences and antige n (85-kd phosphoprotein [pp85]) by nested polymerase chain reaction and imm unohistochemical analysis, respectively. Results: Human herpesvirus 7 DNA sequences and expression of the HHV-7-spec ific immunodominant pp85 antigen were found in 1 (8%) of 13 lesional skin b iopsy specimens of pityriasis rosea. The prevalence of HHV-7 DNA sequences and antigens is even slightly lower in lesional skin of patients with pityr iasis rosea than in clinically and morphologically normal skin of 14 contro l persons, in Z of whom (14%) HHV-7 DNA sequences and antigens could be det ected. Conclusion: The low detection rate of HHV-7 DNA sequences and antigens argu es strongly against a causative role for HHV-7 in the pathogenesis of pityr iasis rosea.