Genital Zoster Infection: the Great Imposter

Herpes simplex virus 1 (HSV-1), herpes simplex virus 2 (HSV-2), and varicella-zoster virus (VZV) are taxonomically closely related viruses that produce clinically distinct diseases but share common features of infection. HSV-1 and HSV-2 both produce cutaneous and mucocutaneous primary infections followed by reactivation disease occurring at the same or a nearby anatomic site. Primary VZV infection, also known as chickenpox, is usually a childhood disease that produces pox-like cutaneous lesions distributed over the entire body. Reactivation VZV infection, often called herpes zoster, generally occurs later in life but, unlike HSV disease, produces pox-like lesions at a different anatomic location, typically along dermatomes. As such, the clinical differential diagnosis of reactivation HSV infection and zoster is generally based upon the anatomic location and the appearance of the lesion(s). The recent availability of molecular assays has resulted in the unexpected diagnosis of zoster infections in male and female patients who presented with genital lesions. The purpose of this article is to present a brief overview of HSV and VZV infections and to relate a laboratory experience that resulted in the diagnosis of zoster infections using a molecular assay in which almost 10% of the 282 positive VZV specimens were from genital sites.