This chapter mainly focuses on acute herpes zoster (HZ). HZ, also known as shingles, is an infectious disease involving reactivation of the varicella-zoster virus (VZV), which resides primarily within the dorsal root ganglia. The estimated lifetime risk of developing HZ is up to 30% with a dramatic increased risk after age 50. Pain with HZ is a combination of normal and neuropathic pain that reflects acute tissue and neural injury. A thorough history and physical examination are important for delineating the dermatomal distribution involved, and the time since the onset of symptoms. Most cases of HZ can be diagnosed clinically, although atypical rashes may require a direct immunofluorescence assay for VZV antigen or a polymerase chain reaction assay for VZV DNA in cells from the base of lesions after they are unroofed. The goals of therapy are pain relief, decreasing viral replication, and prevention of PHN.