I've had outbreaks for years when I get stressed out. The Dr. couldn't diagnose it until I went with the blisters still with puss, then she took a sample of that.
When I have outbreak I take Valtrax - 1 every 12 hours for 6 pills, and it goes away. The Dr. told me to always have a prescription refill handy so I can take it at the first sign of an outbreak.
I'd bet that's what it is. If the Valtrax fixes it, the itching will go away within minutes, then you'll know for sure.