Seek help with my anal itching...

I've first had the anal itching problem about 6 yrs ago. It would suudenly start, last for about 30 min to an hour and then stop. It used to happen a few times a day. No other symptoms. I was raised in the family where everybody washed their bottoms after they do number two, so I did the same thing since I was 3 yrs old, and in my case the itch had absolutely nothing with being clean. After two months I went to the pharmacy and bought some hemmoridal ointment which helped. But one night, after a party and a few shots, I started feeling pressure down there and I saw bluish veine- I knew I got hemorrhoids which I took care of by myself, using ointments and creams. Itch disappeared although I did feel same pressure a couple of times more, after drinking shots usually. I have been itch free until about two years ago. It started at night. I saw my physician about it and he told me to use Aveeno anti-itch cream after washing. It did help but didn't solve my problem. It gives me relief of about 12 hrs, but then I have to repeat the process all over again. Now, my itch can go away for 10 days, even a month, but it always comes back and I am sick of it! I do not have hemorrhoids- at least not visible ones, I do not have any problems with digestive system whatsoever (no constipation, no diarrhea, no pain, no cramps- nada!)- I watch what I eat- a lot of fiber. The skin around my anus doesn't look irritated in any way- it is completely normal. BUT IT ITCHES, and driving me nuts! I know for sure that I don't have any kind of parasites. Does anyone have any idea how to get rid of this terrible itch? I greatly appreciate any advice.