I believe you are right on the spot!
And if you look at the remedies on the site I sent you, and the things
people have tried in this forum , everything thats on that list has been tried but
not in the right order. For example Evening primrose with out the antifungal, and descaling agent wont work/\. Some have tried antifungals but not the antiinflamatory and anti keratan. Some have tried the antikeratain but not the anti fungal along with the anti-inflamatory.
I think the excess kertain needs to be treated butthe antiinflamatory with the antifungal alone will cure this in a month or 2. However
if you look at the link it states you need an antiinflamatory,antifungal and anti keratain(descaling agent). Seborriac dermatitis encompasses all 3 of those things.
I would try the anti inflamatory primorose and the antifungal(lotramin is good one) and see would happens. I think the antifungal will reduce the scales and peeling and primorose will reduce the inflamation.