11 Symptoms Used to Diagnose Lupus
What is lupus?
Lupus isn't rarearound 1.5 million Americans, mostly women, are affected. But lupus can be misdiagnosed as rheumatoid arthritis or another condition. And symptoms that seem like lupus can sometimes be due to a virus.
The American College of Rheumatology says that if a patient has at least 4 of these 11 signs (though not necessarily all at the same time) they can be diagnosed with lupus.
While about 30% of lupus patients typically get this rash, it can also be due to rosacea or other skin conditions, and this symptom alone is not enough to make a diagnosis of lupus.
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Exposure to sunlight or other sources of ultraviolet light (even artificial) can worsen a lupus patient’s butterfly rash. It can also trigger sores on other parts of the body, usually on sun-exposed areas, and lead to joint pain and fatigue. Fair-skinned patients tend to be most affected.
However, Dr. Gilkeson warns that this symptom can be overused in diagnosis: "It is a confusing one," he says. "A lot of people say that they are sun-sensitive."
Mouth or nasal sores
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Dr. Belmont notes that at least two joints, typically smaller ones, have to be persistently affected for at least six weeks for the symptom to qualify as one of the four diagnostics.
Inflammation of the lining of the heart or lung
Even though the inflammation rarely affects the functioning of either the heart or lungs, it can cause sharp chest painespecially when a person is coughing or taking a deep breathand may occasionally spark shortness of breath.
A healthy kidney filters proteins out of the blood as it creates urine, explains Dr. Belmont. But if the kidney is inflamed and not functioning properly, as can be the case with lupus, proteins may sneak into the urine.
These abnormalities don’t usually cause symptoms. However, if the loss of protein (specifically albumin) is substantial, the feet may swell. And if someone has progressed to kidney failure, he or she might have some nausea and weakness.
Seizures or psychosis
For less specific symptoms like headaches, it can be difficult to tease apart whether they are caused by lupus, the medications used to treat it, or the stress of living with the disease.
"It’s not just a low blood count. The condition is actively destroying the cells," explains Dr. Gilkeson, adding that certain lab tests can tell the types apart.
While relatively common in SLE, discoid rashes can also stand alone in a diagnosis of discoid lupus, a type that affects only the skin. The singer Seal has been diagnosed with discoid lupus and has facial scars as a result.
Positive ANA test
ANAs are proteins made by the body that can attach to DNA and other substances inside cells. But just because they are present in the body doesn’t necessarily mean they will attack these substances. These antibodies are found in at least 5% of the general population, so there are "many more people walking around with ANAs who are perfectly healthy or have some illness that has nothing to do with lupus," adds Dr. Belmont.
Other antibody tests
"These confirmatory antibodies are very critical to the accuracy and reliability of the diagnosis," says Dr. Belmont. The series of tests, combined with the ANA, he adds, will usually provide a fairly reliable answer.