Ayurvedic Treatmenti have had psoriasis (with athritis) for 30 years since i was 17. i have tried a number of natural treatments and creams (including weekly PV, diet restriction, and dead sea trips), - most of them give relief but it is a persistant beast and hard work to keep on top of and as a chronic sufferer i have trouble living without things like gluten,caffiene and a bit of alcohol.
This is left field but easily the most effective treatment i have found is an ayervedic cleanse known as 'panchakarma'. it takes 10-14 relaxing days for about an hour a day- involving fasting, herbal treatments, herbal oil applications, and steam baths. After 14 days i am not only feeling energised and healthy the psoriasis is 98% gone. the main difference from other treatments is it stays gone for 3-4 years. i am off to india shortly for the 4th time. after 4 years my psoriasis is starting to come back but is still only about 40% of what it was before my 1st cleanse.
i go to Dr Raos (treatment is individualised so an experienced Dr is best) at Puttaparthi 2 hours north of Bangalore south india (it is where guru sai babas ashram is so is well set up for westerners). It is very clean, rural, and pleasant except march- july when its too hot. The cleanse only costs about $200 US-almost embarassingly cheap. there are resort style clinics on the Kerala coast that will cost 10 times that or more and maybe some clinics in other parts of sth india and many countries but i imagine its cheaper to fly to india and probably better treatment. Good luck