What is it?

It is a skin infection caused by a microorganism called varicella-zoster virus (VZV). The virus is so named because it is the agent responsible for both chickenpox and herpes zoster. Usually the first contact we have with VZV in childhood and manifests clinically as chickenpox. After this infection, the virus migrates to nerve endings from the skin to the lymph and there is latent, reappearing on the skin in certain situations giving rise to the so-called herpes zoster.