I had gone through your medical presentations and understood your concerns. After carefully observing the nature of your symptoms, the probable cause of your condition may be sun allergy. Sun allergy or photosensitivity is a very common abnormality seen in some patients. Sun allergies are triggered by changes that occur in sun exposed skin. Coming to your case, as you had autoimmune disease, immune system recognizes some components of the sun as foreign body and activates immune system against them. This produces an allergic reaction that takes the form of a rash or blisters. You can confirm it by following: 1. skin biopsy, in which a small piece of skin is removed and examined 2. Blood tests to rule out systemic lupus erythematosus 3. Photo-testing, in which a small area of your skin is exposed to measured amounts of ultraviolet light There is no need to worry but we should be careful while dealing with autoimmune diseases. Avoid exposure to sunlight and use corticosteroid cream. Hoping for a speedy recovery.