Following a chicken pox infection, the varicella zoster virus that causes chicken pox persists in the body and resides and remains dormant in the nerve ganglion. When the virus reactivates, it results in Herpes zoster and presents as painful red rashes with blisters along the along distribution of the nerve. The varicella zoster virus causes both chicken pox and herpes zoster. It is very unlikely to get herpes zoster without previously having had a chicken pox infection.
It is possible that the past history of chicken pox was not recalled or it was a mild infection that went unnoticed. There are also rare report of cases of shingles in patients who had received the chicken pox vaccination.
You can do a blood test to test for the antibodies to the varicella zoster virus to determine if you have had a previous chicken pox infection.
