Background and Objectives. To examine specifically the role of sympathetic block in the prevention of postherpetic neuralgia by its application in the treatment of acute herpes zoster.

Methods. Data sources included a Medline search and cross-referencing of articles and text books. A total of 84 references were reviewed. Peer-reviewed articles were selected according to their relevance to the subject and originality. The data were critically analyzed by the author with the specific intention of avoiding bias.

Results. The opinion of the medical community is divided on the role of sympathetic block in preventing postherpetic neuralgia because of the lack of controlled trials and the conflicting retrospective reports as to its effectiveness. While many reports promote the early use of sympathetic blocks during acute herpes zoster to prevent postherpetic neuralgia, others deny their value.

Conclusions. Considering the degree of uncertainty, and the seriousness of postherpetic neuralgia, sympathetic block in addition to treatment with acyclovir should be considered early during acute herpes zoster. Large controlled trials are needed to provide the necessary scientific evidence.