Mine started on my scalp when I was about 15, just thought it was dandruff, nothing stopped it, then 30 years later it was everywhere, not mega serious but a pain, literally, I got the internal version too, Psoriatic Arthritis.
Then, when I moved to LOS, symptoms got better, one year latter no pain tablets, I even got back in the gym, just got back to thinking I had dandruff, but a bit more naughty than that, but with the cream I found it is manageable.
What every I ate or drank made no difference, soap and clothes/bedsheets washing powder type did....🤔