Vaginal itching

I got a blood test, std test, and checked for BV & yeast and was told my ph was perfect. Had negative results for all stds. But I have slight vaginal itching. And when I say very slight I mean very slight. Like every so often it comes and goes but noticeable enough for me to worry. My dr said I may have contact derm and to use hydrocortisone cream. Bc the itching is not internal I have no bumps or blisters bc he checked for that too (everything that I saw about hsv said most dr recognize it instantly)