What is shingles? Shingles (herpes zoster) are an outbreak of rash or blisters on the skin that is caused by the same virus that causes chicken pox-the varicella-zoster virus. The first sign of shingles is often burning or tingling pain, or sometimes numbness, in or under the skin.hingles (herpes zoster) are an outbreak of rash or blisters on the skin that is caused by the same virus that causes chicken pox-the varicella-zoster virus.