Systemic Lupus Erythematosus
Defining Lupus continued...
Lupus is a complex disease, and its cause is unknown. It is likely that a
combination of genetic, environmental, and possibly hormonal factors work
together to cause the disease. Scientists are making progress in understanding
lupus, as described here and in the "Current Research" section of this
booklet. The fact that lupus can run in families indicates that its development
has a genetic basis. Recent research suggests that genetics plays an important
role; however, no specific "lupus gene" has been identified yet.
Studies suggest that several different genes may be involved in determining a
person's likelihood of developing the disease, which tissues and organs are
affected, and the severity of disease. However, scientists believe that genes
alone do not determine who gets lupus and that other factors also play a role.
Some of the factors scientists are studying include sunlight, stress, certain
drugs, and infectious agents such as viruses.
It is likely that a combination of...factors work together to cause the
In lupus, the body's immune system does not work as it should. A healthy
immune system produces proteins called antibodies and specific cells called
lymphocytes that help fight and destroy viruses, bacteria, and other foreign
substances that invade the body. In lupus, the immune system produces
antibodies against the body's healthy cells and tissues. These antibodies,
called autoantibodies, contribute to the inflammation of various parts of the
body and can cause damage to organs and tissues. The most common type of
autoantibody that develops in people with lupus is called an antinuclear
antibody (ANA) because it reacts with parts of the cell's nucleus (command
center). Doctors and scientists do not yet understand all of the factors that
cause inflammation and tissue damage in lupus, and researchers are actively
Symptoms of Lupus
Each person with lupus has slightly different symptoms that can range from
mild to severe and may come and go over time. However, some of the most common
symptoms of lupus include painful or swollen joints (arthritis), unexplained
fever, and extreme fatigue. A characteristic red skin rash-the so-called
butterfly or malar rash-may appear across the nose and cheeks. Rashes may also
occur on the face and ears, upper arms, shoulders, chest, and hands. Because
many people with lupus are sensitive to sunlight (called photosensitivity),
skin rashes often first develop or worsen after sun exposure.