Herpes zoster (or simply zoster), commonly known as shingles, is a viral isease characterised by a painful skin rash with blisters in a limited area on one side of the body. The initial infection with varicella zoster virus (VZV) causes the acute (short-lived) illness chickenpox, and generally occurs in children and young people. Once an episode of chickenpox has resolved, the virus is not eliminated from the body but can go on to cause shingles—an illness with very different symptoms—often many years after the initial infection.