Carly is a 32-year-old female with no reported PMH. She lives in upstate NY, works in IT and loves to spend a lot of time outdoors hiking, fishing and camping. Over the past 9 months she has developed progressive fatigue, malaise, myalgias, polyarticular arthralgias (principally in her hands, wrists and knees), as well as frequent dermatologic eruptions including photosensitivity. Further questioning reveals that she also has frequent xerostomia. She denies any recent trauma and she denies a history of tick bite, though she admits she cannot be certain since she spends so much time outdoors. Initial laboratory evaluation reveals normocytic, normochromic anemia (Hb 10.2 g/dL), borderline renal insufficiency (serum creatinine 1.18 mg/dL) and microscopic proteinuria. Her thyroid function panel is within normal limits. Based on this information:
List your top 3 differential diagnoses. List them in order from most probable to least probable and explain your rationale.