Slide show: Common skin rashes

Shingles (herpes zoster) is a pain rash caused by the chickenpox (varicella-zoster) virus. If you've ever had chickenpox, the virus remains inactive in nerve tissue. Years later, the virus may reactivate, causing shingles.

A shingles outbreak may start with vaguely uncomfortable sensations, itching or pain with no obvious external cause. Within several days, clusters of small blisters — similar to the chickenpox rash — appear in a defined area on one side of your body. Over a few more days, the blisters break, leaving behind sores that crust over. Within about four weeks, the crusts fall off, and the pain and itching usually go away.

Antiviral drugs may lessen your pain or decrease the likelihood of persistent pain after the rash has healed. A shingles vaccine is recommended for most people age 60 or over.