Why Do I Have A Burning Sensation And Sometime Itching

Why do I have a burning sensation and sometime itching between my legs. i am a female.I was using ticnatin powder and I discontinue it.I used a cream recommended by my doctor.It worked at first.I've been using it for a month,but now the burning is coming back.I stopped every thing and it's still burning.There is no redness and no rash.What do I do now.
Diane L.