the association of human herpes virus 6 ( hhv-6 ) and hhv-7 with pr suggest that antiviral agents can be tried to speed up recovery of pr . till date , supportive care with topical emollients and antihistamines is practiced by dermatologists for this disorder . oral erythromycin was once reported to be of benefit to patients with pr , but recent clinical experiences suggest that the use of macrolides may not be useful in the treatment of pr . studies evaluating acyclovir in pr are being conducted worldwide , however , data on indian patients is scarce . we undertook this trial to evaluate the safety and effectiveness of acyclovir among indian patients with pr . the study was designed as a single center , observer - blind , randomized ( 1:1 ) , parallel - group , add - on phase iv trial . eligible subjects were consecutive , consenting adult patients ( > 18 years ) of either sex clinically diagnosed as pr at the dermatology outpatient department of a teaching hospital in eastern india . exclusion criteria were pregnant and lactating women , advanced disease of vital organs , history of sensitivity to acyclovir or cetirizine , and suspicion of mimicking diseases ( fungal infection , psoriasis , or eczema ) . the study was approved by the institutional ethics committee and written informed consent was obtained from all subjects . the trial was registered with the clinical trial registry - india and bears the registration number - ctri/2013/12/004240 . subjects were allocated , using a computer - generated randomization schedule ( simple randomization by 1:1 allocation ) , to one of two treatment groups , a and b. standard of care in the form of tablet cetirizine ( 10 mg od at bed time ) and calamine lotion was given to both groups . group a in addition received tablet acyclovir ( 400 mg thrice a day for 7 days ) . ct 20313 , date of expiry june 2016 , manufacturer bengal antibiotics , west bengal , india ) , calamine ( linical , batch no . a00812 , date of expiry december 2013 , manufacturer palsons drugs private limited , west bengal , india ) were used . the physician evaluating the effectiveness and safety parameters was thus unaware of the treatment group of the patient making the trial observer - blind . this was calculated to detect a difference of 3 units in visual analogue scale ( vas ) ( vide infra ) between groups , with 80% power and 0.05 probability of type 1 error , assuming a standard deviation of 2.5 for this parameter . considering 10% possible dropout rate , this translated to a recruitment target of approximately 24 subjects overall . the effectiveness parameters were vas , appearance of new lesions , lesional score and pruritus . decrease in itch was assessed by the patients using vas of 1 - 10 . lesional score was calculated by addition of erythema score , scaling score and number of lesions score , wherein presence or absence of erythema meant an erythema score of 1 and 0 respectively ; presence or absence of scaling meant a scaling score of 1 and 0 respectively ; < 30 lesions was given a score of 1 , 30100 lesions were given a score of 2 and > 100 lesions scored 3 . pruritus was graded as 0 ( absent itching ) ; 1 - mild ( itching present but not disturbing life ) ; 2 - moderate ( disturbing , but not hampering daytime activities and/or sleep ) ; 3 - severe / intense ( disturbing and hampering daytime activities and/or sleep ) . response to therapy was categorized as : ( a ) complete response - no new lesions , disappearance of all previous lesions , with or without residual postlesional pigmentation ; ( b ) partial response - a few new lesions , regression or disappearance of some previous lesions ; ( c ) no response - no regression of lesions , appearance of new lesions . safety assessment included vital signs , treatment - emergent clinical adverse events and routine hematological and biochemical tests . the laboratory tests were done at baseline and after one week of therapy with trial medication , and included hemoglobin , total and differential leukocyte count , platelet count , creatinine , total and conjugated bilirubin , aspartate aminotransferase , alanine aminotransferase , alkaline phosphatase and fasting blood glucose . the numerical data were analyzed using unpaired t - test or mann  whitney u - test ( as applicable ) and the qualitative data were analyzed using the chi - square test and fisher 's exact test . p value within a group was evaluated by friedman 's anova followed by post - hoc dunn 's test . medcalc version 10.2 ( mariakerke , belgium : medcalc software , 2011 ) and graphpad prism version 5 ( san diego , california : graphpad software inc . , 20057 ) was used for statistical analysis , and p < 0.05 was considered statistically significant . modified intention to treat analysis was done with subjects reporting for at least one postbaseline follow - up . the flow chart of study participants is depicted in figure 1 . of the 27 subjects screened consolidated standards of reporting trials flowchart of study participants in table 1 , showing the clinico - demographic variables , study groups were comparable at baseline with respect to age , sex , residence , income , occupation and duration of illness . clinico - demographic variables after one week , only 2 out of 12 patients in group a complained of appearance of new lesions which was significantly less than group b where 7 out of 12 patients reported new lesions ( p = 0.046 ) . a promising result was obtained on analyzing the changes on objective , as well as subjective scoring . when lesional scores were evaluated , significant reduction ( p < 0.05 ) was observed in patients of group a from second follow - up itself [ table 2 ] whereas , in patients of group b , the lesional score did not touch the baseline even at the end of the study . the results were similar in case of pruritus score as well [ table 3 ] . complete response was obtained in all patients of group a and 83% patients of group b [ table 4 ] . comparison of vas in the two groups showed similar results as for lesional and pruritus scores [ table 5 ] . changes in lesional score in both groups changes in pruritus score in both groups changes in vas in both groups minor side - effects in the form of sedation , headache , nausea , vomiting , dysguesia were observed in the treatment arms but had comparable incidence in both [ table 6 ] . pityriasis rosea has long been suspected to have an infectious , mainly viral etiology because of its clinical course mimicking viral exanthems and thus , acyclovir supposedly holds promise in its management . macrolides have antiinflammatory and immunomodulatory effects that might affect the course of pr or other cutaneous eruptions . studies have compared the effectiveness of these two drugs , acyclovir and erythromycin in pr . such a study conducted by ehsani et al . on 30 patients with pr showed that patients in the acyclovir group responded significantly better than the patients treated with erythromycin . in another study conducted by amatya et al . , response to oral acyclovir compared with that to oral erythromycin was better and statistically significant in the first , second , fourth and sixth weeks . conducted a similar study with either oral acyclovir ( 800 mg 5 times daily ) or placebo . on the day 14 of treatment , the lesions cleared in 18.5 days in treated patients and 37.9 days in the placebo group . all the above studies were done with high doses of acyclovir ( 4 g / day ) . in our study , substantial symptom relief was obtained with 1.2 g / day of acyclovir , thus exposing the patient to a lower yet effective dose of the drug . earlier clearance of symptoms has a favorable effect on the quality of life of patients of pr treated with acyclovir . our study found that acyclovir offers faster resolution of lesions than supportive symptomatic therapy with cetirizine and emollient thus allaying the anxiety in the minds of patients . though at the end of four weeks we noted similar decrease in the number of new lesions in both treatment groups , itching was significantly less among those treated with acyclovir . double blinding could not be used , and the duration of therapy could not be extended beyond four weeks due to logistical reasons . the unit price of the study drugs in the indian market showed that the cost should not be a major impediment to treatment because the add - on cost for acyclovir for one week was 350 inr ( approximately $ 5.83 ) only . acyclovir offered significantly rapid relief in clinical symptoms of erythema , scaling and pruritus compared with use of standard care of antihistamines and emollients . acyclovir can be safely used in the treatment of pr to achieve faster control of the disease and improvement of the quality of life of patients . a more comprehensive long term trial can give us a deeper insight to the sustained effect of the drug . comparative trials with different dosage schedules may establish the optimum dose and duration of acyclovir therapy in pr .
background : pityriasis rosea ( pr ) is an acute inflammatory dermatosis . the association of human herpes virus 6 and 7 suggests the utility of use of antiviral agents in this disease.aims and objectives : to evaluate the effectiveness and safety of acyclovir in the treatment of pr.methods:an observer - blind , randomized ( 1:1 ) , parallel group , add - on trial was conducted on 24 adult patients with pr . 
 subjects of both group a and b received the standard of care in the form of cetirizine 10 mg od and calamine . 
 group a in addition received acyclovir 400 mg tablets thrice daily for 7 days . 
 both groups were followed up for four consecutive weeks for assessment of effectiveness and adverse events.results:group a complained of significantly fewer new lesions than group b ( p = 0.046 ) . 
 a complete response was obtained in all patients of group a and 83% patients of group b at the end of the follow up period . 
 there was significant reduction in both lesional score and pruritus at second week follow - up in group a and third week follow - up in group b ( p < 0.05 ) . 
 minor adverse effects were observed in both treatment arms.conclusion:acyclovir offered rapid resolution of clinical severity of pr from second week onwards without significantly increased adverse events as compared to supportive therapy alone .