Problems that affect other
parts of the body also may affect the vulva. Psoriasis, for instance, is a skin disease that can appear on the vulva as red, thick, scaly patches that may itch.
Vulvar Dystrophy
A vulvar dystrophy is abnormal skin on the vulva. The skin can be too thin (lichen sclerosus), too thick (hyperplasia), or a mixture of both."
Here is some info too: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3691475/
I'm sorry your gyn isn't being terribly helpful.