Prevalence and molecular characterization of human herpes virus 6 and 7 in patients with pityriasis rosea using polymerase chain reaction in a tertiary care hospital, Puducherry

Rangaraj Murugaiyan, Karthikeyan Kaliyaperumal, Balamurugan Rangasamy


Background: Human herpes virus (HHV) 6 and 7 belongs to Betaherpesviridae a sub-family of Herpesviridae. HHV-6 and HHV-7 are double stranded DNA group viruses. The cause of PR and the disease caused by HHV is not well established. The association of HHV 6 and HHV 7 with pityriasis rosea (PR) is under controversy. The HHV DNA is also detected in normal controls which evidence the non- significance of HHV in the pathogenesis of PR.

Methods: The study design was planned for 35 consecutive cases of pityriasis rosea of all age groups. This study was carried out at the department of Dermatology and Central Research Lab, at Sri Manakula Vinayagar Medical College and Hospital, a tertiary care hospital in Puducherry. Since there is no universally accepted diagnostic protocol for PR, we have planned to detect HHV-6 and 7 DNA by PCR from the lesions of all clinically diagnosed cases of pityriasis rosea.

Results: In contrary to the expected outcome that HHV-6 and HHV-7 positivity would correlate to the possible pathogenesis of the disease, the PCR results of all the 35 samples from clinically suspected PR cases were found to be negative.

Conclusions: We conclude that HHV-6 and HHV-7 viruses may not always play a role in the pathogenesis of the disease. Thus PR speculated to have more than one etiology may have agents other than HHV6 and HHV7 involved in the pathogenesis of the disease.


Human herpes virus, Pityriasis rosea, Polymerase chain reaction

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