Being in the sun

I was diagnosed with psoriasis over 20 years ago. Had been a nudist. My doctor said to me "you are one of the few people I would advise to be in the sun" I took that as a complete approval of my nudist lifestyle and have practiced since,
My dilemma is what one can do during in the winter months, seem unable to control my condition then. Any workable suggestions?
I ain't rich, or pretty, can't sing and my legs are thin.