PAIN AND ITS ASSESSMENT IN HERPES-ZOSTER

Pain typically accompanies acute herpes zoster. In a proportion of pat ients, herpes zoster pain persists well beyond rash healing. This pers isting pain is termed post-herpetic neuralgia (PHN). Because of the su bstantial personal and economic burdens caused by PHN, studies of the pathophysiology of herpes zoster pain and of the efficacy of antiviral treatment in reducing prolonged pain are of great importance. Differe nt methods have been used to examine pain in research on herpes zoster and in clinical trials, making it difficult to compare across studies . There is substantial evidence, however, that demonstrates the import ance of distinguishing acute pain from PHN. Several differences have b een found between acute herpes zoster pain and PHN, including pathophy siological findings, risk factors and pain quality. Recommendations fo r the design and analysis of future trials of antiviral agents in herp es zoster have been recently proposed. These include a definition of P HN and recommended secondary end points for future trials. Adopting th ese recommendations in future research on herpes zoster pain, and in t he design and analysis of future trials, will facilitate comparisons a cross studies of the pathophysiology and prevention of PHN.