Zoster Sine Herpete: An Unusual Presentation

Varicella zoster virus (VZV) commonly causes chicken pox, following which the virus becomes latent in the ganglionic neurons across the entire neuroaxis. Reactivation of VZV typically causes herpes zoster (shingles), with its characteristic dermatomal distribution and post-herpetic neuralgia, as its most common complication. In some rare cases, reactivation of VZV may occur in the absence of the typical skin manifestations, a condition known as zoster sine herpete (ZSH), making the diagnosis of VZV infection extremely difficult, particularly when it presents in the form of one of the rare complications, such as encephalitis, as in the case of our patient. In this case report, we present a case of ZSH in an immunocompetent lady presenting with brief thunderclap headache (TCH) and confusion with no prior history of shingles. The diagnosis was confirmed with the positive polymerase chain reaction (PCR) for VZV with clinical and biochemical cerebrospinal fluid (CSF) resolution following a two-week treatment with intravenous acyclovir, substantiating the diagnosis of ZSH.