Definition
Herpes zoster, commonly known as shingles, is a painful rash caused by the varicella-zoster virus – the same virus that causes chickenpox. After you've had chickenpox, the virus can lie dormant in your body and reactivate later in life as shingles. It usually appears as a stripe of blisters on one side of the body. Think of it like a sequel no one asked for. Vaccination can help prevent shingles, and antiviral medications can shorten its duration and severity. It's not contagious like chickenpox, but you can spread chickenpox to someone who hasn't had it.