My grandfather has it. My father has it. I have it. None of my uncles or other relatives have it on that side of the family. My brother has a mild case of it.
On other side of the family, a cousin of mine has it but afaik
no one else on that side has it. its strange.
Personally i dont generally find it that painful most of the time or even itchy now i've got used to it, but i've only had it a couple years so maybe thats yet to come.
In my short experience i've generally found that being OUTSIDE, regardless of how you feel is the best thing for it. In winter my scalp becomes one giant flake but in summer its barely worse than dandruff.