Talk to Gynecologist on Anal Itching

I have anal Itching problem since few months, it's gets worse after periods and during bowel movements. because of itching I also get scratches and slight bleeding in them. what could be the reason? how to treat? I have seen a Dr thrice she changes medicines and creams everytime but still it isn't cured. burning and soreness occurs. while in washroom I feel my skin is tearing apart.