lupus, noninfectious chronic disease in which antibodies in an individual's immune system attack the body's own substances. In lupus, medically known as lupus erythematosus, antibodies are produced against the individual's own cells, causing tissue inflammation and cell damage. Because the vascular and connective tissue of any body organ may be affected, various symptoms may result. Generalized symptoms include fever, weakness, weight loss, anemia, enlargement of the spleen, and a characteristic butterfly-shaped skin rash on the face. Heart, joint, and kidney disease are common (see nephritis). It is believed that the disease may be triggered by certain drugs or foreign proteins, exposure to ultraviolet radiation, or extreme stress. The disease, which may range from mild to fatal, occurs commonly in young women. It is treated with immunosuppressive drugs and steroids. See immunity; autoimmune disease.

Either of two inflammatory autoimmune diseases, both more common in women. In the discoid type, a skin disease, red patches with grayish brown scales appear on the upper cheeks and nose (often in a butterfly pattern), scalp, lips, and/or inner cheeks. Sunlight worsens it. Antimalarial drugs may help. The second type, systemic (disseminated) lupus erythematosus (SLE), may affect any organ or structure, especially the skin (with marks like those of the discoid type), kidneys, heart, nervous system, serous (moisture-forming) membranes (e.g., in synovial joints or lining the abdomen), and lymph nodes, with acute episodes and remissions. Symptoms vary widely. Kidney and central-nervous-system involvement can be life-threatening. Treatment includes pain relief, control of inflammation, and trying to limit damage to vital organs.

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