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What Is Lupus?

Lupus is an autoimmune disease in which the immune system mistakes the body's connective tissue for a foreign invader and attacks it. There are times when the disease gets better and times when it gets worse. Some people with lupus suffer only minor inconvenience. Others suffer lifelong disability.

Lupus affects people of African, Asian or Native American descent three times as often as it affects whites. Nine out of 10 lupus patients are women. The disease usually strikes between age 15 and 45.

There are two kinds of lupus: discoid lupus erythematosus (DLE) and systemic lupus erythematosus (SLE).

DLE affects only skin that is exposed to sunlight.

SLE is more serious. It affects the skin and other vital organs, often causing a raised, scaly, butterfly-shaped rash across the bridge of the nose and cheeks that can leave scars if it goes untreated.

Systemic lupus may also damage the connective tissue in the joints, muscles and skin, as well as the membranes surrounding the lungs, heart, kidneys and brain. SLE can also cause kidney disease. Brain involvement is rare, but lupus can cause confusion, depression, seizures and rarely, strokes.

Blood vessels may come under attack. This can cause sores to break through the skin, especially in the fingers. Some lupus patients get Raynaud's syndrome, in which the small vessels in the skin tighten up and don't let enough blood get to the hands and feet -- especially in response to cold. Most attacks last only a few minutes, but can be very painful.

What Causes It?
No one thing is known to cause lupus. Research suggests that a combination of genetic, hormonal and immune system factors may be behind it. A predisposition to developing the disease does appear to be inherited.

Environmental elements, ranging from viral and bacterial infections to severe emotional stress or overexposure to sunlight, may play roles in provoking or triggering the disease. Certain drugs such as the blood pressure drug hydralazine and the heart rhythm drug procainamide may cause lupus-like symptoms. High estrogen levels resulting from pregnancy, estrogen replacement therapy, and oral contraceptives may aggravate lupus.