Yup, me too. I get a super itchy, bumpy, inflamed rash on my arms, face, neck, etc if in the sun. I've had that reaction for years - long before my AS and then dermatomyositis diagnosis. That probably should have been my first clue!
I now wear sunscreen on my face daily year around and when sunny, almost always have on a hat and a UV protective long sleeved lightweight shirt on. Between all that and the oxygen gear I look like a nut but it helps me be out in the world.