I had a touch of Psoriasis years ago, then started with coffee enemas and taking the toxin load off fixed it.
Since I now believe that most of the excessive toxin load comes from parasites I wouldn't doubt that zappers will work. Keep in mind that you either need to add a way to detox or go VERY slowly since zappers (especially the Ultimate Zapper) can kill off a ton of micro parasites which will cause a toxin spike.
Ozone is great for this, the Beck’s blood purifier works and of course the cheapest is the 70 cent coffee enema.