Systemic lupus erythematosus (SLE) is a remitting-relapsing systemic autoantibody and immune complex disease with a similar clinical presentation to that of malignancy and infection. The authors report a case of newly diagnosed SLE and lupus nephritis in a 48-year-old woman with constitutional symptoms and unintentional weight loss. Her presentation was further complicated by pericardial effusion and methicillin-resistant Staphylococcus aureus (MRSA) facial cellulitis and bacteremia. In the context of nonspecific symptoms and a wide initial differential diagnosis, the early consideration of rheumatologic etiologies and the involvement of consultant services led to appropriate diagnostic testing and a timely diagnosis
