If you have itching at the anal orifice then I am wondering if you have pin worms and/or some other kind of parasite that has to come outside to breed.
I did leave a string here on Curezone, not too long ago at all, about how I got rid of pinworms by keeping the orifice slathered in Noxzema for about a week. They can't live in that antiseptic, it is soothing to the area, and they can't breed in that area. Just a thought.
If you work around little kids, I have read one person on the net saying 1/4 has pinworms. Don't know if that is true or not.