Is sebderm like this and can it spread to other areas of the body and be completely unresponsive?

I have an unknown condition for over 3 years that was originally explained as sebderm but it's always progressing. My main symptoms are redness, burning, folliculitis and sometimes thick scaling that requires scraping to get it off

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No treatments have worked at all. I tried everything like steroids, different types of antifungal shampoo, short course of oral antifungals, psoriasis shampoos, mct oil, sulfur soap etc and my condition seems to have spread to my face, neck, back and now recently my feet. Any shampoo I use seems to give me a widespread rash no matter what ingredients and how gentle it is

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I had a biopsy on my scalp and an allergy patch test but nothing was found. I'm at a loss and it's going to be a while til I'm back at a dermatologist to try work out what's going on