Warning: embarrassing topic....really....

Eczema? I tend to get rashes such as what you are describing. Since I have started swiping EXTERNAL crevices with on of the "Rock" type deodorants, the rashes have stopped. There are lots of brands of the thing - it is basically a type of salt sold as a deodorant. Liquid crystal is a roll on type. My allergist said that the reason it worked was likely because the salt kept sweat from irritating skin. I am just happy that I found an inexpensive fix. Hope it helps some.
Laura

Mystie, Tea is on the list of things to avoid with vulvodynia. It's high in oxylates.
I think yhat includes both green and black teas.

JRBear, eczema is usually related to allergies, so perhaps you have some hidden food allergies or sensitivities?
Have you ever tried a dairy free diet? From what I've read, dairy is frequently implicated in eczema problems.