Primary care management of acute herpes zoster: systematic review of evidence from randomized controlled trials.

Although a number of randomized controlled trials of treatment for herpes zoster have been performed, there is no consensus on how it should be managed in general practice. A systematic review of existing trials, including meta-analysis, was performed to determine the efficacy of available therapies in reducing the incidence of postherpetic neuralgia. The treatments studied included antiviral agents, corticosteroids and other drugs which had been studied in randomized trials. Trials were included if the subjects were immunocompetent adults and the intervention was feasible in general practice. The main outcome measure was prevalence of pain at one, three and six months after onset of the acute herpetic rash. Data for each time point were not available for all trials. The quality of studies was also assessed. Pooled analyses of trials with acyclovir failed to detect a significant reduction of pain in the treatment group at one or six months, but found a 35% reduction at three months. Confidence limits were wide, and a modest benefit of treatment cannot be ruled out at one and six months. Pooled analyses were not possible for other treatments, either because too few trials had been performed, or because completed trials demonstrated significant heterogeneity. Many clinical trials in this area have been too small to give reliable results. Variations in the definition and reporting of postherpetic neuralgia create difficulties in combining data from different studies. Firm recommendations for clinical practice are not possible because existing evidence neither confirms nor refutes the hypothesis that treatment during the acute phase of herpes zoster reduces pain later.