Systemic lupus erythematosus (SLE) is an autoimmune disease most common in women of childbearing age. It can affect multiple organ systems. Common manifestations include fatigue, arthritis, rashes, hematologic abnormalities, and kidney involvement. The diagnosis is based on clinical features and autoantibodies. Treatment involves medications to reduce inflammation and suppress the immune system such as antimalarials, corticosteroids, immunosuppressants. Lupus nephritis requires aggressive therapy with corticosteroids and immunosuppressants like cyclophosphamide or mycophenolate mofetil. Research is ongoing into more targeted biologic therapies.