Relief of Acute Herpetic Pain by Intravenous Vitamin C: The Dosage May Make a Difference: Authors' Reply.

Dear Editor:

Thank you for your valuable comments on our study. However, the authors have a different idea of what readers have sent us. The genesis of acute herpetic pain (AHP) is thought to be from inflammation and damage to the dorsal root ganglion (DRG) and peripheral nerves. The inflammatory changes in the DRG can reduce intraneural blood flow, causing hypoxia, endoneural edema, and neural injuries. This process finally leads to the development of neuropathic pain. Because vitamin C acts as a scavenger of the reactive oxygen species, it is hypothesized to have protective effects on the nerve1. So, there were several reports that AHP has improved through high dosage of vitamin C administration. But, in early investigations about vitamin C administration for AHP, most of studies were not in the form of randomized controlled trials123. Although high dosage of vitamin C can improve in acute pain of herpes zoster, it is difficult to determine exactly whether or not to be effective because of the absence of control groups. In order to identify the comments of readers, we believe that randomized, placebo-controlled clinical studies using high dosage of vitamin C in number of herpes zoster patients are necessary.

Our study also has several limitations that are to confirm visual analogue scale (VAS) of pain retrospectively and to doubt the objectivity of VAS score. Nevertheless, the results of our study did not reflect a significant decrease in acute pain, unlike previous studies, but intravenous vitamin C administration was effective in preventing postherpetic neuralgia4. Please note that our study is meaningful in this regard and wishes to be helpful to readers. Thank you very much.