What is Lupus?
Lupus is a complex autoimmune disease. In people with lupus, the immune system turns against parts of the body it is designed to protect. There is much to learn about lupus including:
- symptoms (part 2 of this guide)
- diagnosis (part 3 of this guide)
- treatment (part 4 of this guide)
- staying healthy (part 5 of this guide)
Lupus can affect many parts of the body, including the:
- joints
- skin
- kidneys
- heart
- lungs
- blood vessels
- brain
Although people with lupus may have many different symptoms, some of the most common include:
- fatigue
- painful or swollen joints (arthritis)
- unexplained fever
- skin rashes
- kidney problems
At present, there is no cure for lupus. However, lupus can be effectively treated with drugs, and most people with the disease can lead active, healthy lives. Lupus is characterized by periods of illness, called flares, and periods of wellness, or remission. Understanding how to prevent flares and how to treat them when they do occur helps people with lupus maintain better health.
Two of the major questions researchers are studying are who gets lupus and why. We know that many more women than men have lupus. Lupus is three times more common in African American women than in Caucasian women and is also more common in women of Hispanic, Asian, and Native American descent. In addition, lupus can run in families, but the risk that a child or sibling of a patient will also have lupus is still quite low. It's difficult to estimate how many people have lupus since its symptoms vary widely and its onset is often hard to pinpoint.
Types
There are several types of lupus:
Systemic lupus erythematosus (SLE) is the form of the disease that most people are referring to when they say "lupus." The word "systemic" means the disease can affect many parts of the body. The symptoms of SLE may be mild or serious. Although SLE usually first affects people between the ages of 15 and 45 years, it can occur in childhood or later in life as well. This guide focuses on SLE.
Discoid lupus erythematosus is a chronic skin disorder in which a red, raised rash appears on the face, scalp, or elsewhere. The raised areas may become thick and scaly and may cause scarring. The rash may last for days or years and may recur. A small percentage of people with discoid lupus have or develop SLE later.
Subacute cutaneous lupus erythematosus refers to skin lesions that appear on parts of the body exposed to sun. The lesions do not cause scarring.
Drug-induced lupus is a form of lupus caused by medications. Many different drugs can cause drug-induced lupus. Symptoms are similar to those of SLE (arthritis, rash, fever, and chest pain) and they typically go away completely when the drug is stopped. The kidneys and brain are rarely involved.
Neonatal lupus is a rare disease that can occur in newborn babies of women with SLE, Sjögren's syndrome, or no disease at all.
It is important for women with SLE or other related autoimmune disorders to be under a doctor's care during pregnancy. Physicians can now identify mothers at highest risk for complications, allowing for prompt treatment of the infant at or before birth. SLE can also flare during pregnancy, and prompt treatment can keep the mother healthier longer.
What Causes Lupus?
Lupus is a complex disease, and its cause is unknown. It is likely that a combination of genetic, environmental, and possibly hormonal factors work together to cause the disease. The fact that lupus can run in families indicates that its development has a genetic basis. Research suggests that genetics plays an important role; however, no specific "lupus gene" has been identified yet. Studies suggest that several different genes may be involved in determining a person's likelihood of developing the disease, which tissues and organs are affected, and the severity of disease. However, scientists believe that genes alone do not determine who gets lupus and that other factors also play a role. Some of the factors scientists are studying include:
- sunlight
- stress
- certain drugs
- infectious agents such as viruses
In lupus, the body's immune system does not work as it should. A healthy immune system produces proteins called antibodies and specific cells called lymphocytes that help fight and destroy viruses, bacteria, and other foreign substances that invade the body. In lupus, the immune system produces antibodies against the body's healthy cells and tissues. These antibodies, called autoantibodies, contribute to the inflammation of various parts of the body and can cause damage to organs and tissues. The most common type of autoantibody that develops in people with lupus is called an antinuclear antibody (ANA) because it reacts with parts of the cell's nucleus. Scientists do not yet understand all of the factors that cause inflammation and tissue damage in lupus, and researchers are actively exploring them.
