Postherpetic neuralgia.

This article reviews the definition, epidemiology, pathology, clinical features, and treatment of postherpetic neuralgia (PHN). Much of this information is well established. However, there is some important new information about the pathology that may shed light on the pathogenesis of this disorder. The exciting prospect exists of the prevention of PHN by vaccination and by early, aggressive treatment of herpes zoster. This is important because current treatment approaches have significant limitations. We now have certain antidepressants, anticonvulsants, opioids, and the topical agent lidocaine that have been scientifically shown by randomized controlled trials to be effective in this disorder. However, all of these have a modest effect at best and newer treatments are necessary. Prevention may be very important for the 30% to 50% of the patients who either do not respond at all or do not respond well. Regional anesthetic procedures do not have a good scientific basis for either acute zoster or established PHN, but remain a reasonable alternative for some patients. This article addresses the issue of how effective the current treatments really are and gives practical guidelines for management.