“Lupus is a chronic (long-term) disease that can cause inflammation and pain in any part of your body. It’s an autoimmune disease, which means that your immune system — the body system that usually fights infections — attacks healthy tissue instead.  Inflammation usually happens when your immune system is fighting an infection or an injury. When lupus makes your immune system attack healthy tissue, it can cause inflammation in lots of different body parts. ”

Lupus Foundation of America