detection of human herpes virus 6&7 in pityriasis rosea and the efficacy of acyclovir

Abstract

Background:The exact aetiology of pityriasis rosea (PR) is still unknown as various researches exist aiming to explain the exact cause. The role of Human Herpes Virus(HHV)-6 & HHV-7 DNA in PR patients has been evaluated in many studies with variable results. The rationale behind the use of antiviral in PR is that the course of the disease follows that of a viral exanthem and also probable involvement of HHV 6 and 7 in its etiopathogenesis. The current case-control study aimed at evaluation of the possible relation between HHV-6 & HHV-7 and PR through detection of HHV-6 & HHV-7 DNA in PR patients in comparison to controls and also illumination the therapeutic efficacy of Acyclovir in PR treatment. Patients and methods: This study recruited 40 subjects, 30 PR patients and 10 healthy controls. All patients were subjected to detailed history taking and examination to determine the presence of constitutional symptoms, prutitus, the type of PR and ensuring the duration of PR together with lack of drug intake in the last two weeks. Skin biopsies were taken from all subjects to detect HHV-6 & HHV-7 DNA. We initiated a comparative control study to detect HHV-6 & HHV-7 DNA in lesional and nonlesional skin samples in PR patients by nested PCR. The results of nested PCR of lesional and non-lesional skin samples were compared to well-matched healthy controls. Also, the study included another comparative control study to evaluate the efficacy of oral Acyclovir (in adult 400 mg five times a day and in children 20 mg /kg/day in five divided doses) for treatment of PR patients. The results of oral acyclovir therapy in group 1 were compared to those in a well matched group II receiving no treatment apart from emollients. Results: The results revealed significant presence of HHV-6 DNA in PR lesions in comparison to controls with p=0.035, thus, support a possible relationship between HHV-6 and PR, but there was no significant difference in HHV-7 DNA in PR lesional skin compared to controls (P=0.047). Also, there was significant difference between lesional HHV-7 positive and negative cases regarding the course of the disease by the end of the second week with P-value < 0.05. In addition, there was significant improvement in PR in group 1 patients with acyclovir treatment (P= 0.05) in comparison to patients in group II without acyclovir treatment (P>0.05) by the end of the second week. Conclusion: HHV-6 and HHV-7 may play a role in the pathogenesis of PR and oral acyclovir is helpful in decreasing the severity and shortening the course of the disease in some patient.

Association between Pityriasis Rosea (PR) and HHV-6/HHV-7 Infection: Importance of Sample Selection and Diagnostic Techniques

“…When skin biopsy samples were studied for HHV-6, Watanabe et al [21] detected viral DNA in 12 samples out of 14 cases, similar to the positive study results of Drago et al [24] and Watanabe et al [21] using nested PCR and Broccolo et al [22] using real-time PCR. The studies of Selim et al [14] and Canbolat et al [3] also showed positivity for HHV-7 DNA in tissue samples with significance.…”

“…While seasonal variation, concurrent cases, case clustering, and the observation of virus-like spherical particles on lesional biopsies of the herald patch in electron microscopy studies are the supporting clues, the pathogen has not been identified and real epidemics have not been reported so far. With the present state of knowledge, the benefits of several treatments do not provide strong evidence for or against an infectious etiology [7,14].…”

“…HHV-6 and HHV-7 are the viruses commonly acquired in childhood, with an 80% to 90% seroprevalence in the general population, causing clinically unapparent primary infection and latent infection in specific cells, which remains throughout life. HHV-6 and HHV-7 can reactivate in cases of immunosuppression in transplant recipients and during pregnancy and other viral diseases [4,5,7,14,18,19].…”