A 26-year-old woman was diagnosed with and treated for systemic lupus erythematosus (SLE) in 2002. She was admitted 11 years later with nephrotic-range proteinuria and lupus nephritis and received two doses of rituximab after failing on steroids and mycophenolate mofetil. Four months later, she presented with fever and joint pain/swelling. Gram stains, joint aspirates, and blood culture all yielded negative results for bacteria. She was discharged after treatment for a possible flare of lupus, but two weeks later, she presented again with a cough and shortness of breath in addition to the flare symptoms. Synovial fluid Smears, and cultures yielded positive results for Mycobacterium tuberculosis; similarly, sputum polymerase chain reaction test and culture confirmed pulmonary tuberculosis. Tuberculosis is difficult to diagnose in SLE patients; it may present like or precipitate SLE flare. In this patient a presumed SLE flare turned out to be an aggressive miliary, disseminated tuberculosis.