Frequently Asked Questions

6. What causes shingles?

Shingles is caused by a virus called the varicella-zoster virus -- the one that gave you chickenpox when you were a child. As you recovered from chickenpox, the sores and other symptoms healed, but the virus remained. It is with you for life.

Researchers know that the varicella-zoster virus behaves differently from other viruses, such as the flu virus. Our immune system usually kills off invading germs, but it cannot completely knock out this type of virus. The virus just becomes inactive.

The virus can become active again, especially in the later years of your life when your immune system doesn't protect you as well from infections. The virus travels from the spinal nerve cells and follows a nerve path out to the skin. Nerve endings in the skin become inflamed and erupt in a very painful rash.

Healthcare providers cannot always be sure what the trigger is in each case. They don't know why the virus reactivates in one person with these risk factors, while in another person with the same risk factors, it does not.