Varicella-zoster virus: a re-emerging infection.

Varicella-zoster virus (VZV) causes chickenpox (varicella), becomes latent in cranial nerve and dorsal root ganglia, and can reactivate many years later to produce shingles (zoster) and postherpetic neuralgia (PHN). Elderly and immunocompromised individuals are also at risk for complications of VZV reactivation involving the central nervous system (CNS), including myelitis, large-vessel encephalitis/granulomatous arteritis, small-vessel encephalitis, meningoencephalitis, and ventriculitis. Peripheral nervous system (PNS) complications range from zoster and postherpetic neuralgia to postinfectious polyneuritis (Guillain-Barre syndrome, GBS). These complications can occur with or without cutaneous manifestations. An increase in elderly and immunocompromised individuals will likely result in a higher prevalence of these conditions; therefore, VZV can be seen as a "re-emerging" infection of the early twenty-first century. In this review, we summarize our experience and the existing literature on CNS and PNS complications of VZV reactivation. Special attention is paid to reports of complications without rash, as these entities are more difficult to diagnose.