Neurologic Complications of Varicella-Zoster Virus Reactivation: Clinical and Imaging Features.

Varicella-zoster virus (VZV), a neurotropic α-herpesvirus, establishes lifelong latency in the nervous system after primary infection. Reactivation leads to herpes zoster (HZ), which can result in severe neurologic complications including postherpetic neuralgia, vasculopathy, encephalitis, meningitis, myelopathy, cranial neuropathy, and optic neuritis. These complications may occur even in the absence of a characteristic rash, making early recognition crucial for timely antiviral therapy to maximize the likelihood of a good outcome. Clinical manifestations of VZV-associated neurologic disorders vary and often mimic other infectious and inflammatory conditions, further complicating timely diagnosis. Among available diagnostic imaging modalities, MRI is the most useful modality for diagnosis of VZV-related neurologic disorders. Recent high-resolution MRI techniques, such as three-dimensional fluid-attenuated inversion recovery and MR neurography, increase the sensitivity for detecting subtle signal intensity abnormalities, and vessel wall imaging is capable of noninvasively demonstrating vascular involvement. Accurate diagnosis requires the integration of imaging findings, clinical assessment, and cerebrospinal fluid (CSF) analysis. In particular, the detection of VZV DNA with a polymerase chain reaction test and testing for anti-VZV immunoglobulin G antibodies in CSF are essential. Given the myriad clinical manifestations of HZ, radiologists may be the first to recognize nervous system pathologic conditions that are related to VZV, which is particularly important because the incidence increases in the aging population. The authors provide a comprehensive update on the epidemiologic, pathophysiologic, and imaging features of VZV-related neurologic disorders. Increased awareness and accurate imaging interpretation can expedite diagnosis and facilitate appropriate clinical management of these patients to improve outcomes. ©RSNA, 2026.