What is Lupus?

By Dr. Ananya Mandal, MDReviewed by Benedette Cuffari, M.Sc.

Systemic lupus erythematosus (SLE), which is more commonly referred to as lupus, is a disease that affects the immune system.

Age spots of redness on the face  from systemic lupus erythematosus. Image Credit: Velimir Zeland / Shutterstock

What is lupus?

Normally, the immune system fights infections caused by germs. In the case of lupus, the immune system attacks the body's healthy cells rather than protecting the body.

Lupus can affect almost any part of the body, including the joints, skin, kidneys, heart, lungs, blood vessels, and brain.

For most people, lupus is a mild disease affecting only a few parts of the body. Whereas some patients do not experience inner organ problems, such as those affecting the heart and lungs, others might experience both skin and joint problems. Normally, lupus develops slowly, with symptoms that come and go. For some, it can cause serious and even life-threatening problems.

Even for patients with diseases that affect the normal functioning of their organs, with good care and management and a strong partnership between a patient and their health care provider, the prognosis is good.

Epidemiology

Lupus affects up to 1.4 million people in the United States. It is estimated that 9 in every 10 people who have lupus are women.

Lupus is three times more common in black women than in white women. It is also more common in women of Hispanic/Latina, Asian, and American Indian descent. Black and Hispanic/Latina women tend to develop symptoms at an earlier age than other women. African Americans with lupus often have more severe organ problems, especially with their kidneys.

Each person with lupus has slightly different symptoms that can range from mild to severe and may come and go over time.

Because many people with lupus are sensitive to sunlight (photosensitive), skin rashes often first develop or worsen after sun exposure.

Pathogenesis

In an autoimmune disorder like lupus, the immune system cannot tell the difference between foreign substances and its own cells and tissues. The immune system then makes antibodies that attack the body, which causes inflammation, pain, and damage to various organs.

Sometimes people with lupus experience a "flare," which occurs when some symptoms appear for short periods then disappear. Learning to recognize that a flare is coming can help the patient take steps to cope with it. Many people feel very tired or have pain, a rash, a fever, stomach discomfort, headache, or dizziness just before a flare.

Diagnosis

There is no one test to diagnose lupus, and it may take months or years to make the diagnosis. There is no cure for lupus; however, certain medications and lifestyle changes can help control it.

Causes

The cause of lupus is not known. It is likely that there is no single cause but a combination of genetic, environmental, and possibly hormonal factors that work together to cause the disease.

Lupus is not contagious and to date, no specific "lupus gene" has been identified, despite the fact that it does appear to run in families.

Further Reading

• All Lupus Content
• Lupus Symptoms
• Lupus Diagnosis
• Lupus Flares
• Lupus Treatments