Sometimes, changes in blood counts (low red cell count, or anemia), may cause fatigue, serious infections (low white cell count), or easy bruising or bleeding (low platelet count). Many patients do not have symptoms from low blood counts, however, so it is important for people with lupus to have periodic blood tests in order to detect any problems.
Blood clots are more common in people with lupus. Clots often occur in the legs (called deep venous thrombosis or DVT) and lungs (called pulmonary embolus or PE) and occasionally in the brain (stroke). Blood clots that develop in lupus patients may be associated with the production of antiphospholipid (APL) antibodies. These antibodies are abnormal proteins that may increase the tendency of the blood to clot. Blood can be tested for these antibodies.
What Causes Lupus?
The cause of lupus is unknown. However, there appears to be something that triggers the immune system to attack various areas of the body. That's why suppressing the immune system is one of the main forms of treatment. Finding the cause is the object of major research efforts.
Factors that may contribute to the development of lupus include viruses, environmental chemicals and a person's genetic makeup.
Female hormones are believed to play a role in the development of lupus because women are affected by lupus much more often than men. This is especially true of women during their reproductive years, a time when hormone levels are highest.
The observation that lupus may affect more than one member of the same family has raised the possibility that the tendency to develop lupus may be inherited. Having such a tendency, however, does not predict that a relative will develop lupus. Only about 10% of people with lupus have a close relative with the disease.
How Is Lupus Diagnosed?
Lupus is diagnosed when a person has several features of the disease (including symptoms, findings on examination, and blood test abnormalities). The American College of Rheumatology has devised criteria to assist doctors in making the correct diagnosis of lupus. A person should have at least four of the following 11 criteria, either at the same time or one after the other, to be classified as having lupus. These criteria include:
What Is an Antinuclear Antibody Test?
An antinuclear antibody (ANA) test is a sensitive screening tool used to detect autoimmune diseases, including lupus. Antinuclear antibodies (ANAs) are antibodies that are directed against certain structures within a cell's nucleus (thus, antinuclear antibody). ANAs are found in particular patterns in people with autoimmune diseases (those in which a person's immune system works against his or her own body).