Lupus is a chronic, autoimmune disease that can damage any part/organ of the body. Chronic means that the signs and symptoms tend to last longer than six weeks and often for many years. No one knows what causes lupus. Scientists think that people are born with the genes to develop lupus and that something triggers the disease and symptoms. In lupus, something goes wrong with your immune system, which is the part of the body that fights off infectious agents (viruses, bacteria etc.). Normally our immune system produces proteins called antibodies that protect the body from these invaders. Autoimmune means your immune system cannot tell the difference between these foreign invaders and your body's healthy tissues ("auto" means "self") and creates autoantibodies that attack and destroy healthy tissue. These autoantibodies cause inflammation, pain, and damage in various parts of the body. Symptoms of lupus vary widely depending on the individual case and the form of lupus present. Common symptoms include fatigue, headaches, swollen/painful joints, fever, anemia, swelling around eyes/legs, pleurisy, photosensitivity, rashes, hair thinning and mouth/nose sores. Most people with lupus do not experience all of these symptoms. The outlook for people with lupus was once grim, but diagnosis and treatment of lupus has improved considerably. With treatment, most people with lupus can lead active lives.