Systemic Lupus

Systemic Lupus Erythematosus
(SLE or Lupus)

Medical Author: William C. Shiel Jr., MD, FACP, FACR

• What is lupus? What are the types of lupus?
• What causes lupus? Is it hereditary?
• What is drug-induced lupus?
• What are the symptoms and signs of lupus?
• How is lupus diagnosed?
• What is the treatment for systemic lupus?
• How can a lupus patient help prevent disease activity (flares)?
• How can lupus affect pregnancy or the newborn?
• What does the future hold for patients with lupus?
• Where can one get more information about lupus?
• Systemic Lupus At A Glance
• Related lupus articles:
  Lupus - on WebMD

What is lupus? What are the types of lupus?

Lupus is a condition characterized by chronic inflammation of body tissues caused by autoimmune disease. Autoimmune diseases are illnesses that occur when the body's tissues are attacked by its own immune system. The immune system is a complex system within the body that is designed to fight infectious agents, for example, bacteria, and other foreign invaders. One of the mechanisms that the immune system uses to fight infections is the production of antibodies. Patients with lupus produce abnormal antibodies in their blood that target tissues within their own body rather than foreign infectious agents. Because the antibodies and accompanying cells of inflammation can involve tissues anywhere in the body, lupus has the potential to affect a variety of areas of the body. Sometimes lupus can cause disease of the skin, heart, lungs, kidneys, joints, and/or nervous system. When only the skin is involved, the condition is called discoid lupus. When internal organs are involved, the condition is called systemic lupus erythematosus (SLE).

Both discoid and systemic lupus are more common in women than men (about eight times more common). The disease can affect all ages but most commonly begins from age 20 to 45 years. It is more frequent in African-Americans and people of Chinese and Japanese descent.

What causes lupus? Is it hereditary?

The precise reason for the abnormal autoimmunity that causes lupus is not known. Inherited genes, viruses, ultraviolet light, and drugs may all play some role. Genetic factors increase the tendency of developing autoimmune diseases, and autoimmune diseases such as lupus, rheumatoid arthritis, and immune thyroid disorders are more common among relatives of patients with lupus than the general population. Some scientists believe that the immune system in lupus is more easily stimulated by external factors like viruses or ultraviolet light. Sometimes, symptoms of lupus can be precipitated or aggravated by only a brief period of sun exposure.

It also is known that some women with SLE can experience worsening of their symptoms prior to their menstrual periods. This phenomenon, together with the female predominance of SLE, suggest that female hormones play an important role in the expression of SLE. This hormonal relationship is an active area of ongoing study by scientists.

More recently, research has demonstrated evidence that a key enzyme's failure to dispose of dying cells may contribute the development of SLE. The enzyme, DNase1, normally eliminates what is called "garbage DNA" and other cellular debris by chopping them into tiny fragments for easier disposal. The researchers turned off the DNase1 gene in mice. The mice appeared healthy at birth but after six to eight months, the majority of mice without DNase1 showed signs of SLE. Thus, a genetic mutation in a gene that could disrupt the body's cellular waste disposal may be involved in the initiation of SLE.

What is drug-induced lupus?

Dozens of medications have been reported to trigger SLE; however, more than 90% of this "drug-induced lupus" occurs as a side effect of one of the following six drugs: hydralazine (used for high blood pressure), quinidine and procainamide (used for abnormal heart rhythm), phenytoin (used for epilepsy), isoniazid [(Nydrazid, Laniazid), used for tuberculosis], d-penicillamine (used for rheumatoid arthritis). These drugs are known to stimulate the immune system and cause SLE. Fortunately, drug-induced SLE is infrequent (accounting for less than 5% of SLE among all patients with SLE) and usually resolves when the medications are discontinued.

Lupus - Symptoms at Onset of Disease

The MedicineNet physician editors ask:

The symptoms of lupus can vary greatly from patient to patient. What were your symptoms at the onset of your disease?

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