Herpes zoster infection and postherpetic neuralgia.

Varicella-zoster virus (VZV), the cause of chicken pox, establishes latent infection in sensory ganglia. Reactivation results in zoster (shingles), sometimes complicated by encephalitis (myelitis). Postherpetic neuralgia (PHN) is the major morbidity of zoster. PHN typically increases in frequency with age. The VZV vaccine, which was developed for children, may be effective in enhancing VZV immune reactivity and decreasing zoster in adults. Early antiviral treatment may be effective in decreasing PHN onset. Several other medications may be useful in treating established PHN. A recent report discussed intrathecal steroid use.