Effects of Oral Acyclovir on the Treatment of Pityriasis rosea (PR)

Background: Pityriasis rosea (PR) is an acute self limiting skin disease whose etiology, in spite of, several studies is still unknown. However, there is a hypothesis suggesting that infectious agents specially viral agents like HHV6 and HHV7are responsible for PR.
Materials and Methods: A double-blind, placebo-controlled trial study was performed at a dermatology clinic in Zahedan (Iran) in 2006. One hundred and twenty nine consecutive patients with PR were randomly assigned into two groups: treatment group (n = 65) who were treated for 1 week with oral acyclovir (800 mg 5 times daily) and control group (n = 64) who received placebo (Vitamin E; 100 mg 2 times daily). All the patients were assessed at admission (week 0) and at weeks 1 and 2.
Results: The ratio of female to male participants was 2 to 1consisting 88 females (68/2%) and 41 males(31/8%).In the 7^th and 14^th days of assessment (P=0/001) response to complete treatment and relative treatment in case group showed a statistically significant increase compared to control group. Formation of new lesions in the 1^st week (P=0/006) and in the 2^nd week (P=0.001) had a statistically significant increase in control group in comparison with the case group.
Discussion:  We could not evaluate the efficacy of treatment in virus replication since the rate of HHV7 and HHV6 infection is high; moreover, evaluation of the antibody titer in such patients’ serum especially in adults does not provide valuable information. However, the results of this study showed that high dose of acyclovir can be effective in treatment of patients with PR with sever skin eruption specially if it is administered in the first week of skin eruptions when the replication of virus has a high rate.