I don't do well with any type of grain or fruit (except apples). They all make me itch.... Some make me constipated or give me gas as well. And yes, I've had this dilemma for a long time... But I can have dairy so that's what I do... Protein, dairy, veggies...
Seriously, every time I eat a berry, my anus is the first thing to start itching... I mention it because you mentioned that your anus is itchy. I also start having very strong Sugar cravings if I eat starches or fruits...