I had whitening of my labia many years back and it turned out to be Lichensclerosis. It wasn't so much around my clitoris though, as on the inside and edges of my labia minora. At first it just seemed like they were turning whitish, then they began to itch and the skin became very frail but thicker. I was on Depo Provera at the time and I have to believe that's what caused it. Took 3 years to get back to normal.