Well....I would recommend you used nothing scented in that area and use a soap without added fragrance, etc., i.e. Aveeno, Dove.
Have you changed your laundry detergent?
I would recommend consulting your GYN Specialist to follow this up if this doesn't subside.
I am not douching but I do use a scented body wash, it never really bothered me before though. I have been conscious of where I use it now, though.
I went through that for a while. I felt like my discharge was itching me almost like I was allergic to it. Turns out I have allergic skin. White, bleached toilet paper was one problem. I was so itchy, that both my labias were red raw and the doctors called it puritis. It kind of is a viscious cycle. I'd get itchy scratch. Get the raw bleeding ski and so on. There are non-cortisone type creams to stop the itching. Blow drying yourself down there after a shower also helps. Take care. :)
Are you using sented products?
Douching?
If this persists, you should definitely consult your GYN Specialist as this could be a number of things.