The association of pityriasis rosea with cytomegalovirus, Epstein-Barr virus and parvovirus B19 infections - a prospective case control study by polymerase chain reaction and serology.

A viral aetiology is suspected for pityriasis rosea (PR). The objective was to investigate the association of PR with cytomegalovirus (CMV), Epstein Barr virus (EBV) and parvovirus B19 infections. Patients with PR were recruited in a primary care setting over 18 months. Blood was collected at initial presentation and four weeks later. Controls were the next age-and-sex-matched patients requiring blood collection for non-dermatological disease. Polymerase chain reaction was performed for EBV and parvovirus B19 DNA. Serology was done for CMV, EBV and parvovirus B19. 12 patients with PR and 12 control subjects were recruited. No patient had viral DNA or significant antibody rise against any of the viruses investigated. The seroprevalence of all three viruses and Ab titres in the patients with PR were insignificantly different from those of control subjects. Two patients had IgM detectable against CMV and EBV respectively. Based on other investigation results, we believe that both IgM results were caused by cross reactivity. PR is not associated with CMV, EBV or parvovirus B19 infections.