Causes
It's generally believed that lupus is caused by alterations in the immune system. The body's immune system normally fights foreign bacteria and viruses. However, with lupus, the immune system may fail to recognize "self" substances and will make antibodies that attack the body's own tissue. This is called autoimmunity.
The exact cause of lupus is still unknown. Multiple factors are involved in the development of the disease, including heredity and environmental factors. It is recognized that sunlight causes symptoms to flare up. Other triggers include viral infections, the stress of illness, sometimes pregnancy, and certain medications. Because more women are affected than men, another theory suggests there is a relationship to estrogens.