Dry vulva

The skin around my vagina is dry and flaky, I’m not sure what’s causing it. I’ve been experiencing this on and off for a while, maybe even years. I’ve noticed it’s maybe correlated to arousal. If I go to bed without having sex or masturbating, I itch in my sleep around my vagina and the itchy leads to the dry skin. But also having the dry skin causes me to itch in my sleep even if I have masturbated or had sex. I don’t wear tight clothes super often, but I do almost always wear thongs. I shave fairly infrequently. And I do have a history of eczema but only on the back of my scalp and nowhere else