What Causes Shingles?

Shingles occurs when the virus that causes chickenpox starts up again in your body. After you get better from chickenpox, the virus "sleeps" (is dormant) in your nerve roots. In some people, it stays dormant forever. In others, the virus "wakes up" when disease, stress, or aging weakens the immune system. Some medicines may trigger the virus to wake up and cause a shingles rash. It is not clear why this happens. But after the virus becomes active again, it can only cause shingles, not chickenpox. You can't catch shingles from someone else who has shingles. But there is a small chance that a person with a shingles rash can spread the virus to another person who hasn't had chickenpox and who hasn't gotten the chickenpox vaccine