What Could Itchy, Dry Anus With Rashes Suggest?

hi, i hav been having problems down there.. it started with an itchy and dry anus then in a week or so's time my vargina felt dry n itchy too.. i thought it was because i use baby powder to keep d area dry. but i havnt used it in more than a week n the problem seems to hav gotten worse with a wierd rash around the skin of that area.. i cant seem to understand what exactly is wrong.