How Does Reactivation of the Varicella-Zoster Virus Cause Herpes Zoster?

After an attack of chickenpox, the varicella-zoster virus moves up into the nerves, where it settles down in an inactive form (known as a latent form). It "lies down" inside specific nerve cells (neurons) that relay information to the brain about what your body is sensing -- such as whether your skin feels hot or cold, whether you've been touched, or whether you're feeling pain. These nerve cells lie in clusters (ganglia) adjacent to the spinal cord and brain, and are one type of sensory neurons.

 

As we get older, it is possible for the varicella-zoster virus to "come alive." When this happens, the virus "reactivates" and then moves down the nerves to cause the symptoms of herpes zoster. Research scientists are still trying to understand why this happens and why it happens in some people and not in others.

 

Herpes zoster is most common in people over the age of 50. However, if you have had chickenpox or the chickenpox vaccine, you are at risk of developing herpes zoster. This disease is also more common in people with weakened immune systems from HIV infection, chemotherapy or radiation treatment, transplant operations, or stress.