Systemic Lupus Erythematosus (Lupus)
Key points
- Systemic lupus erythematosus, commonly called lupus or sometimes SLE, is an autoimmune disorder, which means it is caused when immune defenses mistakenly attack the body's own cells rather than protecting them from outside invaders.
- In some patients, lupus causes only mild illness, but in others it leads to potentially deadly complications.
- Your doctor will begin by reviewing your symptoms, your medical history and your exposure to factors that can trigger lupus flares.
- Lupus is a long-lasting (chronic) condition, although there may be periods in which the illness is relatively inactive or even completely quiet.
What Is It?
Systemic lupus erythematosus, commonly called lupus or sometimes SLE, is an autoimmune disorder, which means it is caused when immune defenses mistakenly attack the body's own cells rather than protecting them from outside invaders. In lupus, immune proteins called autoantibodies target cells in many different parts of the body, causing inflammation and tissue damage in the joints, skin, kidney, nervous system (brain, spinal cord and nerves), blood, heart, lungs, digestive system and eyes. Autoantibodies also can attach themselves to specific body chemicals, forming abnormal molecules called immune complexes. When immune complexes deposit in various organs and tissues, they trigger additional inflammation and injury.
The exact cause of lupus remains a mystery, although scientists are investigating many different possibilities. Researchers believe several factors may play a role in the development of the disease. Since 90 percent of all lupus patients are women, usually of childbearing age, researchers think hormones may be involved. Lupus tends to run in families, so genetic factors may play a role. There is some evidence that the illness may be more common in people of African, Native American, West Indian and Chinese ethnic background. Some researchers think lupus may be triggered by a virus or another type of infection in people who are susceptible to the disease.
Lupus is relatively rare, affecting less than one in 2,000 people.
Symptoms
In some patients, lupus causes only mild illness, but in others it leads to potentially deadly complications. Its symptoms tend to come and go in a series of periods of intensified symptoms, called flares, followed by periods of decreased symptoms, called remissions. Flares can be triggered by many different factors, including sun exposure, infection, medication or possibly pregnancy, but often flares occur for no apparent reason.
Lupus has the potential to affect many different parts of the body, so it can cause a wide range of symptoms. They include:
- Malaise (a generally sick feeling)
- Fever
- Loss of appetite
- Weight loss
- Muscle pain, with pain and swelling of the joints
- A butterfly-shaped rash on the cheeks and bridge of the nose, called a malar rash
- Skin photosensitivity (a more widespread rash and flulike symptoms after exposure to sunlight)
- Hair loss
- In about 20 percent of patients, a discoid rash, which appears as firm, round red plaques with raised borders
- Painful ulcers in the mouth, nose and genital regions
Other possible symptoms of lupus include:
Written and revised by
Gerald Hurowitz, M.D.
Our doctors write and review articles for accuracy and keep them up to date.
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