Herpes Zoster Reactivation Following Epidural Steroid Injections: A Comprehensive Chart Review INTRODUCTION- Herpes Zoster (HZ) is a viral infection caused by the reactivation of the Varicella zoster virus within a nerve root.- Patients undergoing procedures involving corticosteroid may be at increased risk of HZ reactivation- We aimed to evaluate the prevalence of herpes zoster reactivation within 31 days after an epidural steroid injection at Mayo Clinic sites.