If several people in the family have anal itching, threadworms might be the cause.
I have tried every crème recommended on this website. My Doctor prescribed a powder but that did not work. I would use a back scratcher and scratch until I was raw. Posted by David B4 on 23/10/2017 at The most common cause of anal itch (Pruritus Ani) is the continual rubbing and irritation of the sensitive skin with toilet paper. Posted by finally solved on 06/09/2017 at Two years of suffering from itchy bottom.
They are very common – an estimated 40 million cases in the USA alone.