Sounds like Lupus to me. There is not much info on Sun Sensitivity and RA, but plenty on Lupus. The rash from the sun is a tell tale sign of Lupus. The skin too. Go to a Rheumatologist and have them run a ANA and protein urinalysis on you. If you already have all those symptoms, it is likely Lupus. Schleroderma presents in a much different way than you are describing.