Zinc
★★★★☆
I went to the ER when it was at its worst. 4 times. No help. I got a range of diagnoses from "some kinda rash" to shingles to pellagra! No M.D. ever figured it out. Just prescriptions up the wazoo to treat their guesses. I didn't take them.
After researching off and on for almost 3 years, I finally realized it was psoriasis, which I then researched intensively. After less than a week, it is now 80-90% cleared up! Here's what I did...
I started taking 50 mg of zinc 2X/day. Won't mention brand name, but it's "zinc (as zinc gluconate dihydrate, zinc picolinate)." Chelated. You may want to try a higher dose or take more than twice a day -- I only weigh 88 lbs, so you may want to adjust accordingly.
The sores are 90% gone. All I have left are a few areas of flaky skin, mostly on my shins.
For dead skin clean-up, I'm using a solution recommended by Tony Pantalleresco made of about 16 oz white vinegar, 1 rounded tablespoon of sea salt, and 20 drops of 5% lugol's. Shaken - not stirred. :-) I dampen a wash rag with it and then gently rub off the dead skin.
I won't call this solution a cure, but it will help keep the dead flaky skin to a minimum, and some areas where I've used it have stopped being flaky altogether for about 3 days now (but that could just be the zinc doing its work).
I tried many many things over 3 years' time before I realized what I had, so feel free to ask me about something you're considering.
Zinc
ZINC SUPPLEMENTATION
Your skin contains one fifth of your body's zinc supply. Rats and mice that are deficient in zinc develop a skin condition called keratogenesis that is very similar to human psoriasis (Hoffer and Walker, Orthomolecular Nutrition, p 156-157). Zinc deficiency in humans is the rule, not the exception. The US RDA for zinc is only 15 milligrams a day, and yet the average American takes in even less than that. (Williams, Nutrition and Diet Therapy, 7th ed., page 253) In spite of this, it is most uncommon to find either dietitians or doctors ever recommending a supplement of this mineral.
Research has shown that supplements of zinc are safe up to about 500 mg. daily. A more sensible daily dose of 50 mg to perhaps may be maintained for as long as is desired. A good multiple vitamin along with this will provide some balancing copper, as will (believe it or not) the copper water pipes in your home.
The "amino acid chelated" form of zinc ('chelated zinc') is better tolerated and better absorbed than zinc sulfate or other inorganic forms of the mineral.