Rheumatology and Musculoskeletalcommon
A 29-year-old woman has photosensitive facial erythema, painless oral ulcers and symmetrical pain and swelling of the small joints of both hands. Urinalysis shows 2+ protein and microscopic haematuria; serum creatinine is 108 micromol/L (reference range 45–90), complement C3 is low, and anti-double-stranded DNA antibodies are strongly positive. Which diagnosis best accounts for the findings?