Try essential oils maybe?
http://natadviser.com/essential-oils-for-psoriasis/
Here's how I applied it: I take 100% Tea tree oil, put a cotton ball to the opening of the bottle and quickly pour a tiny drop into the cotton ball. Then Id gently rub it on the areas that irritate me. I did this once a day for a month (sometimes twice cause it was so bad), and noticed very good results. Ive read that 100% Tea tree oil is kind of strong (still not sure why it matters), so some people buy a lower purity % or dilute it themselves, but I was desperate enough to YOLO it. I did not get side effects from it so far so I continue to use that method. (I will add that it might itch or burn a little when applying it to the area for a couple of minutes).