Talk to General Physician on Itching In Surrounding Of Anus

Hello. I have got pruritic ani since 4 months. The itching is at the surrounding, goes to the back of the anus also sometimes causes severe itching at vaginal surrounding too. Its painful, aggrrevated when scratching more. Also, its difficult to wear my undergarment sometimes. It gets severe at night and when i wash myself. Please tell me what should i apply.