Hey, Doyd, I found a message board for psoriasis where you might get better replies to your question. I'm not trying to chase you away, but I did see some safety concerns that made me think you'd appreciate more input.
It's even vBulletin so you'll have an easy time navigating.
http://www.psoriasis.org/forum/index.php?
I hope you'll find the right answers for you.