Systemic lupus erythematosus (SLE) is a chronic, inflammatory autoimmune disorder. It may affect the skin, joints, kidneys, and other organs.

SLE (lupus) is an autoimmune disease. This means there is a problem with the body's normal immune system response. Normally, the immune system helps protect the body from harmful substances. But in patients with an autoimmune disease, the immune system can't tell the difference between harmful substances and healthy ones. The result is an overactive immune response that attacks otherwise healthy cells and tissue. This leads to chronic (long-term) inflammation.

The underlying cause of autoimmune diseases is not fully known. Some researchers think autoimmune diseases occur after infection with an organism that looks like certain proteins in the body. The proteins are later mistaken for the organism and wrongly targeted for attack by the body's immune system.

SLE may be mild or severe enough to cause death.

SLE affects nine times as many women as men. It may occur at any age, but appears most often in people between the ages of 10 and 50 years. African Americans and Asians are affected more often than people from other races.

SLE may also be caused by certain drugs. For information on this cause of SLE, see drug-induced lupus erythematosus.

Symptoms vary from person to person, and may come and go. The condition may affect one organ or body system at first. Others may become involved later. Almost all people with SLE have joint pain and most develop arthritis. Frequently affected joints are the fingers, hands, wrists, and knees.

Inflammation of various parts of the heart may occur as pericarditis, endocarditis, or myocarditis. Chest pain and arrhythmias may result from these conditions.

General symptoms include:

• Fever
• Fatigue
• General discomfort, uneasiness or ill feeling (malaise)
• Skin rash -- a "butterfly" rash over the cheeks and bridge of the nose affects about half of those with SLE. The rash gets worse when in sunlight. The rash may also be widespread.
• Sensitivity to sunlight
• Joint pain and swelling
• Arthritis
• Swollen glands
• Muscle aches
• Nausea and vomiting
• Pleurisy (causes chest pain)
• Pleural effusions
• Seizures
• Psychosis

Additional symptoms that may be associated with this disease:

• Blood in the urine
• Coughing up blood
• Nosebleed
• Swallowing difficulty
• Skin color is patchy
• Red spots on skin
• Fingers that change color upon pressure or in the cold
• Numbness and tingling
• Mouth sores
• Hair loss
• Abdominal pain
• Visual disturbance
• Blood disorders, including blood clots

The diagnosis of SLE is based upon the presence of at least four out of eleven typical characteristics of the disease. The doctor will listen to your chest with a stethoscope. A sound called a heart friction rub or pleural friction rub may be heard. A neurological exam will also be performed.

Tests used to diagnose SLE may include:

• Antinuclear antibody (ANA) panel including anti-DNA and anti-Smith antibodies
• Chest x-ray showing pleuritis or pericarditis
• Urinalysis to show blood, casts, or protein in the urine
• CBC
• Kidney biopsy

This disease may also alter the results of the following tests:

• WBC count
• Serum globulin electrophoresis
• Rheumatoid factor
• Urine protein
• Serum protein electrophoresis
• Mononucleosis spot test
• ESR
• Cryoglobulins
• Coombs' test - direct
• Complement component 3 (C3)
• Complement
• Anti-thyroid microsomal antibody
• Anti-thyroglobulin antibody
• Anti-mitochondrial antibody
• Anti-smooth muscle antibody