Answer: the herpes zoster is a viral infection caused by the same varicela virus. If JP had varicela before, the virus could reactivate in a way that does not produce varicela, but zoster.
Explanation: Herpes zoster is an infection caused by varicela-zoster virus. When someone had varicela, this virus remains "latent" in the nervous tissue and could be reactivated in elderly people, or in those with diseases like HIV; when the immune system is not so strong.
The classic presentation is a painful eruption in the skin, mostly located in the back.
