Immunohistochemical Study for the Differential Diagnosis between Herpes Simplex and Varicella-zoster Infections

Shim, Sang Dai; Kim, You Chan; Park, Hyang Joon; Cinn, Yong Woo

Abstract

BACKGROUND
The clinical distinction between herpes simplex virus (HSV) and varicella-zoster virus(VZV) skin infections is sometimes difficult. Potentially, immunohistochemical method can distinguish HSV from VZV infection. However, immunohistochemical studies for the differentiation between them have rarely been reported. OBJECTIVE: The purpose is to investigate the usefulness of immunohistochemical staining in differentiation between HSV and VZV infections. METHODS: We studied 9 cases of herpes zoster, 4 cases of chicken pox, and 5 cases of herpes simplex with monoclonal antibody to VZV. Routine histopathologic findings of the cases were also evaluated. RESULTS: All cases of VZV infections stained with antibody to VZV, but none of HSV infection stained. In VZV infection, 25% of the cases showed strong or diffuse positive reaction, whereas the rest of them showed weak or focal pattern. Histopathologically, the degree of inflammation was significantly greater in HSV infection than in VZV infection. However, vaculitis was more frequently found in VZV infection than in HSV infection. CONCLUSION: We think immunohistochemistry with antibody to VZV is very useful in the differentiation between HSV and VZV infections, even if the reaction pattern may be so weak or focal, as careful interpretation is necessary.