Shingles is a viral infection that causes a painful rash. Shingles can occur anywhere on your body. It typically looks like a single stripe of blisters that wraps around the left side or the right side of your torso. Shingles is caused by the varicella-zoster virus — the same virus that causes chickenpox. After you've had chickenpox, the virus stays in your body for the rest of your life. Years later, the virus may reactivate as shingles.