Systemic lupus erythematosus (disseminated lupus erythematosus or lupus) is a chronic inflammatory connective tissue disorder that can involve joints, kidneys, mucous membranes, and blood vessel walls.
About 70 to 90% of people who have lupus are young women in their late teens to 30s, but children (mostly girls) and older men and women can also be affected. Lupus occurs in all parts of the world but may be more common among blacks and Asians.
The cause of lupus is usually not known. Occasionally, the use of certain drugs (such as hydralazine and procainamide, which are used to treat heart conditions, and isoniazid, which is used to treat tuberculosis) can cause lupus. Drug-induced lupus usually disappears after the drug is discontinued.
The number and variety of antibodies that can appear in lupus are greater than those in any other disorder. These antibodies, which are the underlying physiologic problem in lupus, along with other unknown factors, may sometimes determine which symptoms develop. However, the levels of these antibodies may not always be proportional to the person's symptoms.
Discoid lupus erythematosus is a form of lupus that affects only the skin. In this condition, raised round rashes occur, sometimes with scarring and hair loss in affected areas. In 10% of people, manifestations of systemic lupus—for example, those affecting the joints, kidneys, and brain—may occur but are generally mild.
Symptoms vary greatly from person to person. Symptoms may begin suddenly with fever, resembling a sudden, severe (acute) infection. Or symptoms may develop gradually over months or years with episodes (called flare-ups) of fever, feeling unwell, or any of the symptoms discussed below alternating with periods when symptoms are absent or minimal.
Migraine-type headaches, epilepsy, or severe mental disorders (psychoses) may be the first abnormalities that are noticed. Eventually, however, symptoms may affect any organ system.
Joint symptoms, ranging from intermittent joint pains (arthralgias) to sudden inflammation of multiple joints (acute polyarthritis), occur in about 90% of people and may exist for years before other symptoms appear. In long-standing disease, marked joint deformity may occur (Jaccoud's arthropathy) but is rare. However, joint inflammation is generally intermittent and usually does not damage the joints.
Skin and Mucous Membrane Problems:
Skin rashes include a butterfly-like redness across the nose and cheeks (malar butterfly rash); raised bumps or patches of thin skin; and red, flat or raised areas on the face and sun-exposed areas of the neck, upper chest, and elbows. Blisters and skin ulcers are rare, although ulcers do commonly occur on mucous membranes, particularly on the roof of the mouth, on the inside of the cheeks, on the gums, and inside the nose. Generalized or patchy loss of hair (alopecia) is common during flare-ups. Mottled red areas on the sides of the palms and up the fingers; redness and swelling around the nails; and flat, reddish purple blotches between the knuckles on the inner surfaces of the fingers also may occur. Purplish spots (petechiae) may occur because of bleeding in the skin as a result of low platelet levels in the blood. Sensitivity to sunlight (photosensitivity) occurs in most people with lupus, particularly fair-skinned people.
It is common for people with lupus to feel pain when breathing deeply. The pain is due to recurring inflammation of the sac around the lungs (pleurisy), with or without fluid (effusion) inside this sac. Inflammation of the lungs (lupus pneumonitis), resulting in breathlessness, is rare, although minor abnormalities in lung function are common. Life-threatening bleeding into the lungs may rarely occur. Blockage of arteries in the lung caused by the formation of blood clots (thrombosis) can also occur.
People with lupus may have chest pain due to inflammation of the sac around the heart (pericarditis). More serious but rare effects on the heart are inflammation of the walls of the coronary arteries (coronary artery vasculitis), which can lead to angina (see Coronary Artery Disease: Angina), and inflammation of the heart muscle with scarring (fibrosing myocarditis), which can lead to heart failure (see Heart Failure). The valves of the heart can rarely be involved and may need to be surgically repaired. People are at increased risk of coronary artery disease.
Lymph Node and Spleen Problems:
Widespread enlargement of the lymph nodes is common, particularly among children, young adults, and blacks of all ages. Enlargement of the spleen (splenomegaly) occurs in about 10% of people. People may experience nausea, diarrhea, and vague abdominal discomfort. The occurrence of these symptoms may be the forewarning of a flare-up.
Nervous System Problems:
Involvement of the brain (neuropsychiatric lupus) can cause headaches, mild impairment of thinking, personality changes, stroke, epilepsy, severe mental disorders (psychoses), or a condition in which a number of physical changes may occur in the brain, resulting in disorders such as dementia. The nerves in the body or spinal cord may also be damaged.
Kidney involvement may be minor and without symptoms or may be relentlessly progressive and fatal. The most common result of this impairment is protein in the urine that leads to swelling (edema) in the legs.
The numbers of red blood cells, white blood cells, and platelets may decrease. Platelets assist in blood clotting, so if these numbers decrease greatly, bleeding may occur. Also, and for other reasons, the blood may clot too easily, which accounts for many of the problems that can affect other organs (such as strokes and blood clots to the lungs or recurrent miscarriages).
Gastrointestinal Tract Problems:
Impairment of blood supply to various parts of the gastrointestinal tract may result in abdominal pain, damage to the liver or pancreas (pancreatitis), or a blockage or tear (perforation) of the gastrointestinal tract.
Pregnant women have a higher-than-normal risk of miscarriage and stillbirth.
Doctors suspect lupus mainly on the basis of the person's symptoms and findings during a careful physical examination, particularly in a young woman. Nonetheless, because of the wide range of symptoms, distinguishing lupus from similar diseases can be difficult.
Laboratory tests can help doctors confirm the diagnosis. A blood test can detect antinuclear antibodies, which are present in almost all people who have lupus. However, these antibodies also occur in other diseases. Therefore, if antinuclear antibodies are detected, a test for antibodies to double-stranded DNA, as well as a test for other autoimmune antibodies (autoantibodies, such as anti-smith antibodies and others), are done. A high level of these DNA antibodies almost definitely means the person has lupus, but not all people who have lupus have these antibodies. Other blood tests, such as measuring the level of complement, are also performed and can help to predict the activity and course of the disease in some people. Women with lupus who have repeated miscarriages or have had problems with blood clots should be tested for antiphospholipid antibodies. This is an important test when planning contraceptive methods or pregnancy. This blood test, which detects antibodies to phospholipids, can help identify people at risk of recurrent blood clots. Women with positive antibodies to phospholipids should not take estrogen-containing oral contraceptives and should choose other methods of contraception. Blood tests can also indicate anemia, a low white blood cell count, or a low platelet count.
Laboratory tests can detect the presence of protein or red blood cells in the urine or an elevation of creatinine in the blood. These findings indicate kidney damage caused by inflammation of the filtering structure in the kidneys (glomeruli), a condition referred to as glomerulonephritis. Sometimes a kidney biopsy (removal of tissue for examination and testing) must be performed to help the doctor plan treatment. People who have lupus should be tested from time to time for kidney damage even if they have no symptoms. Testing includes blood and urine tests.
Lupus tends to be chronic and relapsing, often with symptom-free periods that can last for years. Flare-ups can be triggered by sun exposure, infection, surgery, or pregnancy. Flare-ups occur less often after menopause. Because many people are being diagnosed earlier than in the past and because better treatment is available, the prognosis has improved markedly over the last two decades. However, because the course of lupus is unpredictable, the prognosis varies widely. Usually, if the initial inflammation is controlled, the long-term prognosis is good. Early detection and treatment of kidney damage reduce the incidence of severe kidney disease.
Treatment depends on which organs are affected and how active the inflammation of lupus is. The severity of the lupus is not necessarily the same as the activity of the inflammation. For example, organs may be permanently damaged and scarred from lupus that caused inflammation in the past. Such damage may be referred to as “severe,” even if the lupus is not active (that is, it is not causing any inflammation or any further damage at this time). The goal of treatment is to decrease the activity of lupus—that is, to decrease inflammation, which in turn should prevent damage.
If lupus is not very active (sometimes called mild lupus), treatment may not need to be intensive. Nonsteroidal anti-inflammatory drugs (NSAIDs—see Pain: Nonsteroidal Anti-Inflammatory Drugs) often can relieve joint pain. Hydroxychloroquine, chloroquine, or quinacrine, sometimes taken in combination, helps relieve joint and skin symptoms. Sunscreen lotions (with a sun protection factor of at least 30) should be used, especially by people who have skin rashes.
Very active lupus (sometimes called severe lupus) is treated immediately with a corticosteroid such as prednisone (see Joint Disorders: Corticosteroids: Uses and Side Effects. The dose and duration of treatment depend on which organs are affected. Sometimes an immunosuppressive drug such as azathioprine or cyclophosphamide is given to suppress the body's autoimmune attack. Mycophenolate mofetil is an alternative immunosuppressive drug. The combination of a corticosteroid and an immunosuppressive drug is most often used for severe kidney disease or nervous system disease and for vasculitis.
Once the initial inflammation is controlled, a doctor determines the dose that most effectively suppresses inflammation over the long term. Usually, the dose of prednisone is gradually decreased when symptoms are controlled and laboratory test results show improvement. Relapses or flare-ups can occur during this process. For most people who have lupus, the dose of prednisone can eventually be decreased or occasionally discontinued.
Surgical procedures and pregnancy may be more complicated for people who have lupus, and they require close medical supervision. Miscarriages and flare-ups during pregnancy are common. Pregnancy should be avoided during a flare-up, and conception should be delayed until the disease seems likely to be inactive.
People who take corticosteroids should be tested periodically and, if necessary, treated for osteoporosis (thinning of the bones), which can occur with chronic corticosteroid use. People should be monitored closely by a doctor for coronary artery disease. Other risk factors for coronary artery disease (for example, high blood pressure and high cholesterol levels) should be controlled as well as possible.
Last full review/revision February 2008 by Rula A. Hajj-ali, MD