Varicella zoster virus encephalitis

VZV encephalitis refers to a neurological complication associated with the Varicella-zoster virus (VZV), which can cause varicella (chickenpox) during primary infection and herpes zoster (shingles) upon reactivation. While VZV infections are common, encephalitis occurs more rarely, with an estimated incidence of 1–2 cases per 10,000 varicella cases. This condition primarily affects adults and infants.


Neurological signs: patients with VZV encephalitis may present with symptoms such as headache, fever, vomiting, seizures, sensory changes, and altered levels of consciousness.

Motor abnormalities: ataxia (loss of coordination), hypertonia or hypotonia (increased or decreased muscle tone), hyperreflexia or hyporeflexia (increased or decreased reflexes), and hemiparesis (muscle weakness on one side of the body) are also possible.

Rash presence: although encephalitis often occurs alongside the characteristic rash of chickenpox or shingles, it can also manifest without this rash.


Diagnosing VZV encephalitis involves a combination of clinical assessment and diagnostic tests. Detection of VZV DNA in the central spinal fluid (CSF) is a key diagnostic method. Other laboratory tests may be performed to rule out other potential causes of encephalitis. Neuroimaging using EEG and MRI scans may identify abnormalities in brain activity and structure.


Acyclovir, a potent antiviral drug, is the primary treatment for VZV encephalitis. Administering acyclovir early can help reduce the severity and duration of the illness. Patients may require supportive measures, including hydration and management of symptoms such as fever and seizures.

Consequences of VZV Encephalitis

The outcomes of VZV encephalitis vary widely, ranging from complete recovery to various degrees of residual effects. Mortality rates range from 5% to 15%, highlighting the seriousness of this condition6. Patients who survive may experience long-term neurological consequences, including cognitive impairment, motor deficits, and seizures.


Vaccination against varicella has been integrated into national immunization programs in numerous countries. Proper vaccination can prevent varicella and subsequently reduce the risk of VZV encephalitis. Practicing good hygiene and avoiding contact with individuals experiencing active VZV infections can help prevent transmission.

In conclusion, VZV encephalitis is a rare but serious neurological complication associated with VZV infections. Timely diagnosis, appropriate treatment, and prevention measures, such as vaccination and public awareness, play essential roles in managing this condition and reducing its impact on individuals’ health and well-being.



By Prav Prathapan, Encephalitis International, and reviewed by Dr Sylviane Defres,
Consultant Infectious diseases, Tropical and Infectious diseases Unit, Liverpool University
Hospitals Foundation NHS Trust, Liverpool School Tropical Medicine and Institute of
Infection Veterinary and Ecological Sciences, University of Liverpool

FS071V1 Varicella zoster virus encephalitis

Date created: August 2023/Last updated: August 2023/ Review date: August 2026

Disclaimer: We try to ensure that the information is easy to understand, accurate and up to date as possible. If you would like more information on the source material and references the author used to write this document, please contact Encephalitis International. None of the authors of the above document has declared any conflict of interest, which may arise from being named as an author of this document.

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Page Created: 16 February 2024
Last Modified: 26 March 2024
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