Just seen this. A year ago I was in the same boat, and had tried everything anyone has mentioned here. So I went to a proper trichologist and she diagnosed whatever it was (genuine, true, but I've forgotten the name off-hand). Thing is, she has cured it - as in: it will never not be there potentially but can be kept totally under control with the proper shampoos and soothing lotions. This is not cheap and one always suspects a scam. But she works with Philip Kingsley half the week, and the rest of the week up here, and is highly experienced and qualified, and the point is, it has worked. No trouble since last summer, no scales visible even with 5x lenses. One thing she warned was not to put conditioner on our scalps (no one, ever) as it is too inflammatory. AND - that we are washing our scalps, not our hair - she says enough runs down the hair to get off normal grime etc on the hair without actually washing the hairs. So you could ask for a referral to a trichologist, is what I'm saying. Then you might not have to pay! We weren't sure what had caused my problem, diabetes or low iron or sudden change of diet etc but it's stable now and that's all that matters.
DG