I’ve had this for 13 years. It’s horrible and embarrassing. It’s more common than acknowledged- search the web and there’s lots of people trying to find a solution. I don’t even post because I’ve found it too embarrassing even anonymously online!
Went to the GP once and was given hydrocortisone 1%,which works when used and doesn’t when not. And its not a good area to use it a lot so I’d restrict it to when it got really bad
Have otherwise tried different cloths, germolene, sun (don’t ask), some chilli based drug (awful), aqueous cream (awful), nappy creams (all of them),baby wipes, different loo rolls. I often think I’ve cracked it then a couple of days it’s back again
But I think I’ve found my solution - it’s like having a portable bidet - it’s cheap
www.<a class="break-all" href="https://amazon.co.uk/Gogogo-Portable-Handheld-Personal-Bathroom/dp/B078N72TH9/ref=mp_s_a_1_5?s=gateway&crid=35C6UP9F3HK8Y&keywords=bidet%20sprayer%20portable&sprefix=bidet%20sprayer&qid=1553926690&sr=8-5&tag=mumsnet&ascsubtag=mnforum-general-health-3546482-Pruritus-ani" rel="nofollow" target="_blank">amazon.co.uk/Gogogo-Portable-Handheld-Personal-Bathroom/dp/B078N72TH9/ref=mp_s_a_1_5?crid=35C6UP9F3HK8Y&keywords=bidet+sprayer+portable&qid=1553926690&s=gateway&sprefix=bidet+sprayer&sr=8-5
It’s a bit noisy so not really for public toilets but at home it’s amazing. Two whole weeks itch free.
Can change my username back now but I do hope this post this helps someone - it’s a really horrible thing to have.
HTH