Viral Encephalitis and acute Cerebellar Ataxia Due to Late Reactivation of Varicella- Zoster Virus in an Immunocompetent Child

Reactivation of latent Varicella-Zoster virus may cause various neurological complications including meningitis, encephalitis, myelitis, vasculopathy resulting in stroke and pseudotumor cerebri. It occurs mainly in elderly or immunocompromised patients and is very rare in children. We report a 4-year and 6-months old immunocompetent boy who developed encephalitis and cerebellites, due to reactivation of latent Varicella-Zoster virus (VZV). Characteristic skin lesions of varicella were absent. Varicella-Zoster virus DNA was weakly positive in cerebrospinal fluid and serum Varicella-Zoster virus immunoglobulin G was positive while immunoglobulin M remained negative. Although rare, Varicella-Zoster virus may reactivate to cause significant central nervous system disease even in immunocompetent children. We highlight the importance of keeping a high degree of suspicion as the typical rash may not associate the disease. The key for correct diagnosis is the temporal relationship between the symptom appearance and elevated anti-VZV antibodies in serum (immunoglobulin G) or the presence of VZV DNA (PCR) in cerebrospinal fluid.