Reactivation of oral herpes simplex virus: implications for clinical management of herpes simplex virus recurrence during radiotherapy.

Herpes viruses are characterized by their ability to establish and maintain latent infections that can be reactivated. Several stimuli can trigger the reactivation of herpes viruses, which are perhaps best recognized in the recurrent blisters and ulcers associated with herpes simplex virus. We present two clinical cases of reactivation of herpes simplex virus during radiation therapy for management of cancers of the head and neck. Although the role of ionizing radiation in the reactivation of herpes simplex virus has not been established, we review the viral and host events associated with the establishment of orofacial herpes simplex virus infection, latency, and reactivation of the virus. We discuss current models of viral reactivation and suggest directions for further clinical research into the reactivation of orolabial herpes simplex virus during radiotherapy.