Are you really tired all the time? Do you have frequent headaches? Are your joints swollen and painful? It may not be the flu or a similar illness. You may have lupus, a chronic autoimmune disease that causes systemic inflammation that affects multiple organs, especially the skin and joints. Lupus can also affect other organs in your body such as your kidneys, the tissue lining your lungs (pleura), your heart (pericardium) and your brain.