I have written an article on skin conditions, that goes into a more in depth approach to psoriasis. Current studies have proven that a vitamin D3 deficiency is a contributing factor in most auto immune conditions, where as psoriasis is an over active immune system. As well as an essential fatty acid deficiency. Essential fatty acids are the good fats, such as olive oil,fish, flax,coconut, and walnut oil, as well as nuts and seeds. They may be added to the diet, or taken in supplement form. I use coconut oil, and eat it. I don't have psoriasis, but it is very helpful for dry skin, and hair. Apply to the face at night, and leave on. It is a natural, not synthetic, moisturizer.
Taking a d3 supplement, and applying d3 cream, has been shown to help psoriasis. This is why alot of doctors recommend sunshine for skin conditions.
Drinking plenty of pure filtered water, will help to clear the body of toxins, as well as keeping the skin hydrated. 1/2 oz. per pound of body weight, daily.
It is also helpful to take a good probiotic, as most skin conditions have been linked to dysbiosis. http://hubpages.com/health/Natural-Supplements-for...