Lupus fact sheet

What is lupus?

Lupus (LOO-puhss) is a chronic, autoimmune (aw-toh-ih-MYOON) disease. It can damage any part of the body (skin, joints, and/or organs inside the body). Chronic means that the signs and symptoms tend to last longer than six weeks and often for many years. In lupus, something goes wrong with your immune system, which is the part of the body that fights off viruses, bacteria, and other germs ("foreign invaders," like the flu). Normally your immune system produces proteins called antibodies that protect the body from these invaders. Autoimmune means your immune system cannot tell the difference between these invaders and your body's healthy tissues ("auto" means "self"). In lupus, your immune system creates autoantibodies (AW-toh-AN-teye-bah-deez), which sometimes attack and destroy healthy tissue. These autoantibodies contribute to inflammation, pain, and damage in various parts of the body.
When people talk about "lupus," they usually mean systemic lupus erythematosus (ur-uh-thee-muh-TOH-suhss), or SLE. This is the most common type of lupus. It is hard to guess how many people in the U.S. have lupus, because the symptoms are so different for every person. Sometimes is not diagnosed. The Lupus Foundation of America thinks that about 16,000 new cases are reported across the country each year.
Although lupus can affect almost any organ system, the disease, for most people, affects only a few parts of the body. For example, one person with lupus may have swollen knees and fever. Another person may be tired all the time or have kidney trouble. Someone else may have rashes. Over time, more symptoms can develop.
Normally, lupus develops slowly, with symptoms that come and go. Women who get lupus most often have symptoms and are diagnosed between the ages of 15 and 45. But the disease also can happen in childhood or later in life.
For some people, lupus is a mild disease. But for others, it may cause severe problems. Even if your lupus symptoms are mild, it is a serious disease that needs constant monitoring and treatment. It can harm your organs and put your life at risk if untreated.
Although the term “lupus” commonly refers to SLE, there are several kinds of lupus:

Systemic lupus erythematosus, or SLE, makes up about 70 percent of all cases of lupus. SLE can be mild or severe and can affect various parts of the body. Common symptoms include fatigue, hair loss, sensitivity to the sun (photosensitivity), painful and swollen joints, unexplained fever, skin rashes, and kidney problems. In general the diagnosis of lupus is based off of a combination of physical symptoms and laboratory results.
Cutaneous (kyoo-TAY-nee-uhss) lupus erythematosus can be limited to the skin or seen in those with SLE. “Cutaneous” means “skin.” Symptoms may include rashes/lesions, hair loss, vasculitis (swelling of the blood vessels), ulcers, and photosensitivity. A doctor will remove a small piece of the rash or sore and look at it under a microscope to tell if someone has skin lupus and what form it is. There are two major kinds of cutaneous lupus:
- Discoid (DISS-koid) lupus erythematosus, also called DLE, mainly affects the skin. The discoid rash usually begins as a red raised rash that becomes scaly or changes color to a dark brown. These rashes often appear on the skin on the face and scalp, but other areas may also be affected. Many people with DLE have scarring. Sometimes DLE causes sores in the mouth or nose. A doctor will remove a small piece of the rash or sore and look at it under a microscope to tell if someone has DLE. If you have DLE, there is a small chance that you will later get SLE. Currently there is no way to know if someone with DLE will get SLE.
- Subacute cutaneous lupus erythematosus makes up 10 percent of lupus cases. About 50 percent of the time, people with subacute cutaneous lupus also have SLE. Subacute cutaneous lupus causes skin lesions that appear on parts of the body exposed to sun. These lesions do not cause scars.
Drug-induced lupus is a form of lupus caused by certain medicines. The symptoms of drug-induced lupus are like those of systemic lupus, but only rarely affect major organs. Symptoms can include joint pain, muscle pain, and fever, and are mild for most people. Most of the time, the disease goes away when the medicine is stopped. However, not everyone who takes these drugs will get drug-induced lupus. The drugs most commonly connected with drug-induced lupus are used to treat other chronic conditions, such as seizures, high blood pressure, or rheumatoid arthritis. Examples include procainamide (Pronestyl®, Procanbid®); hydralazine (Apresoline®; also, hydralazine is an ingredient in Apresazide® and BiDil®); phenytoin (Dilantin®); etanercept (Enbrel®); and adalimumab (Humira®).
Neonatal lupus is a rare condition in infants that is caused by certain antibodies from the mother. These antibodies can be found in mothers who have lupus. But it is also possible for an infant to have neonatal lupus even though the mother is healthy. However, in these cases the mother will often develop symptoms of lupus later in life. At birth, an infant with neonatal lupus may have a skin rash, liver problems, or low blood cell counts, but these symptoms disappear completely after several months and have no lasting effects. Infants with neonatal lupus can also have a rare but serious heart defect. With proper testing, physicians can now identify most at-risk mothers, and the infant can be treated at or before birth. Most infants of mothers with lupus are healthy.