Lupus is a chronic autoimmune disease in which your immune system mistakenly attacks your own healthy tissues and organs. The word itself comes from the Latin term for “wolf,” first used in medical writing around 850 AD to describe skin lesions that resembled a wolf’s bite. Today, when people say “lupus,” they’re almost always referring to systemic lupus erythematosus (SLE), the most common and serious form. An estimated 204,000 people in the United States have SLE, and about 9 out of 10 of them are women.
How Lupus Affects the Body
In a healthy immune system, antibodies target foreign invaders like bacteria and viruses. In lupus, the body produces autoantibodies that instead target your own cells, particularly the genetic material inside them. These autoantibodies, called antinuclear antibodies (ANAs), can appear in the blood years before any symptoms show up.
The autoantibodies clump together with cellular debris to form immune complexes, which then deposit in organs like the kidneys, skin, heart, and brain. Once lodged there, they trigger inflammation and tissue damage. Normally, the body has cleanup systems that clear this debris, but in lupus those systems are impaired. The immune complexes pile up, fueling a cycle of worsening inflammation.
The kidneys are especially vulnerable. Between 40% and 50% of people with lupus develop kidney involvement, which can progress to kidney failure if not managed. Cardiovascular events, including heart attacks and strokes, occur in roughly 9% of lupus patients with kidney disease. The disease can also affect the joints, lungs, nervous system, and blood cells, which is why it’s called “systemic”: it can reach virtually any part of the body.
Types of Lupus
SLE is the form most people mean when they say “lupus.” It affects multiple organ systems and ranges from mild to life-threatening. But there are other forms worth knowing about.
- Cutaneous lupus is limited to the skin. The most well-known subtype is discoid lupus (DLE), which causes scaly, disk-shaped patches on the face, neck, and scalp. These patches expand slowly, then heal with discolored skin and sunken scars. On the scalp, discoid lupus can cause permanent hair loss. It’s more common in smokers and Black Americans.
- Drug-induced lupus looks similar to SLE, with joint pain and inflammation around the lungs, but it’s triggered by certain prescription medications. Drugs used for high blood pressure, irregular heart rhythms, tuberculosis, and acne have all been linked to it. Symptoms typically resolve once the medication is stopped.
Common Symptoms
Lupus is often called “the great imitator” because its symptoms overlap with many other conditions. The most recognizable sign is the butterfly rash (also called a malar rash): a flat or raised red patch that spreads across the bridge of the nose and both cheeks, sparing the creases beside the nostrils. It can be temporary or persistent.
Beyond the rash, lupus commonly causes joint pain and swelling, extreme fatigue, fevers with no clear infection, hair loss, mouth sores, and sensitivity to sunlight. Some people experience chest pain from inflammation of the lining around the heart or lungs. Neurological symptoms like seizures, confusion, or psychosis can occur in more severe cases. The disease tends to cycle between flares, when symptoms worsen, and quieter periods of remission.
Who Gets Lupus
Women of childbearing age, between 15 and 44, face the highest risk of developing SLE. The gender gap is dramatic: roughly 184,000 of the 204,000 Americans with SLE are female. Lupus also disproportionately affects people of color. Black and American Indian/Alaska Native women are two to three times more likely to develop the disease than white women. Hispanic and Asian populations are also affected at higher rates.
The reasons for these disparities aren’t fully understood, but genetics, hormones, and environmental triggers all play a role. Estrogen appears to influence immune activity, which partly explains why the disease overwhelmingly affects women during their reproductive years.
How Lupus Is Diagnosed
There’s no single test that confirms lupus. Diagnosis relies on a combination of blood work and clinical symptoms. The first step is usually an ANA blood test. A positive result doesn’t mean you have lupus (many healthy people test positive), but a negative result makes lupus very unlikely.
If the ANA is positive, doctors look for a pattern of symptoms across seven clinical categories: constitutional signs like fever, blood abnormalities, neurological symptoms, skin involvement, inflammation of the heart or lung lining, joint problems, and kidney issues. They also check three categories of immune markers in the blood. Each finding carries a different weight, and a combined score of 10 or more points toward an SLE diagnosis. Importantly, each symptom only counts if lupus is the most likely explanation, not some other condition.
Treatment and Management
Lupus has no cure, but treatment can control symptoms, prevent flares, and protect organs from long-term damage. The cornerstone medication is hydroxychloroquine, an antimalarial drug now recommended for virtually all lupus patients as a long-term treatment. It reduces disease activity in mild to moderate cases, lowers the frequency of flares, and has a meaningful impact on long-term survival.
Corticosteroids are commonly prescribed to tamp down inflammation quickly, but they come with significant side effects over time, including cardiovascular, metabolic, and bone problems. One of hydroxychloroquine’s most valuable roles is reducing the amount of steroids a patient needs. For more severe disease, particularly when the kidneys are involved, stronger immune-suppressing medications are added to the treatment plan.
The goal of treatment is to keep the disease as quiet as possible between flares while minimizing medication side effects. With modern management, the 10-year survival rate for people diagnosed with SLE is about 93%, a dramatic improvement over past decades when the disease was far more often fatal.