Sun (a few hours a week) is very important in the spring and summer. I suggest no sunscreen until you are prepink but i do use sunscreen on my face (if there is no P) because the face makes little Vitamin D and since it is most often exposed to damaging UV light and more at risk of radiation damage using sunscreen on the face is a cautious decision.
Due to genetic reasons, vitamin D isn't as effective for some but the sun does things other then only producing vitamin D and this is also important in reducing the Psoriasis . Some (310-316nm) wavelengths can destroy tcells or immune cells which are involved with inflammation and psoriasis. Some wavelengths can cause special cells in the skin to make a high test form of vitamin D (calcitriol) which can effect these tcells by changing their behavior and also reducing blood vessel formation, a side effect of natural immune wound healing proteins found in elevated levels in psoriatic skin.
