Systemic Lupus Erythematosus
Systemic lupus erythematosus (SLE), commonly called lupus, is a chronic autoimmune disease that can cause inflammation in many parts of the body. It develops when the immune system, which normally protects the body from infections, becomes misdirected and attacks the body's own cells and tissues.
Lupus can affect almost any organ, but commonly involves the:
- Joints – causing pain, stiffness or swelling
- Skin – causing rashes, including rashes that may worsen with sun exposure
- Kidneys – causing inflammation known as lupus nephritis
- Blood and blood cells – causing anemia, low white blood cell counts or low platelet counts
- Heart and lungs – causing inflammation of the tissues surrounding these organs or, less commonly, the organs themselves
- Brain and nervous system – causing a wide range of neurologic or cognitive symptoms in some patients
Because lupus can affect multiple organs and systems throughout the body, it is called a systemic autoimmune disease.
Lupus is different for every person
One of the defining features of lupus is its wide variation from person to person. Some people have a relatively mild form affecting primarily the skin and joints, while others develop inflammation involving major organs such as the kidneys, lungs, heart, blood vessels or nervous system.
The disease can also change over time. Many people experience periods when lupus becomes more active, called flares, followed by periods when symptoms and inflammation improve, known as remission or low disease activity.
Importantly, symptoms such as fatigue, pain, or difficulty concentrating may significantly affect quality of life even when major organ inflammation is not present.
Why early diagnosis & treatment matter
Uncontrolled inflammation from lupus can lead to permanent organ damage. Early recognition, regular monitoring and appropriate treatment can help control inflammation, prevent flares, protect organs and reduce the risk of long-term complications.
There is currently no cure for lupus, but treatment has advanced considerably. With modern therapies and careful long-term management, many people with lupus can achieve good disease control and lead active, fulfilling lives.
Because lupus can affect different organs in different ways, treatment is individualized. A rheumatologist typically coordinates care and may work closely with nephrologists, dermatologists, neurologists, pulmonologists, cardiologists and other specialists when needed.
Who gets lupus?
Anyone can develop lupus, but the disease is much more common in women. About 9 out of 10 people with systemic lupus erythematosus (SLE) are women, and the disease most often begins between the ages of 15 and 45. However, lupus can develop at any age, including during childhood or later adulthood.
Several factors are associated with an increased likelihood of developing lupus:
- Sex: Women are affected much more often than men. Hormonal, genetic, and immune-system differences are thought to contribute to this pattern.
- Family and genetics: Having a family member with lupus or another autoimmune disease can increase risk, although most people with lupus do not have a close relative with the disease.
- Race and ethnicity: In the United States, lupus is more common in Black, Hispanic/Latino, Asian and American Indian/Alaska Native populations than in White populations. Some groups also experience higher rates of certain serious manifestations, including kidney disease.
These differences are complex and likely reflect an interaction of genetic susceptibility, environmental exposures, social determinants of health and differences in access to healthcare. No single factor determines who will develop lupus.
Most importantly, lupus is not directly inherited from parent to child. Rather, a person may inherit a greater susceptibility to autoimmune disease, which can interact with other factors to contribute to the development of lupus.
What causes lupus?
The exact cause of lupus is not known. Research suggests that lupus develops through a complex interaction between genetic susceptibility, the immune system, hormones and environmental factors. No single gene, infection, exposure or lifestyle factor causes lupus on its own.
In people who are susceptible, the immune system loses some of its ability to distinguish the body's own cells from potential threats. This can lead to the production of autoantibodies and ongoing immune activation, which may cause inflammation and tissue damage in different parts of the body.
Several factors are thought to contribute:
- Genetics: Many genes can influence the risk of developing lupus. Having a family history of lupus or another autoimmune disease may increase susceptibility, but lupus is not usually passed directly from parent to child.
- Immune system changes: Multiple parts of the immune system can become overactive or poorly regulated. These changes contribute to autoantibody production and inflammation affecting the body's tissues and organs.
- Hormonal and biological factors: Lupus is much more common in women, particularly during the reproductive years. Sex hormones and differences in immune regulation are thought to contribute, although hormones alone do not cause lupus.
- Environmental factors: Certain exposures may contribute to the development of lupus or trigger increased disease activity in susceptible individuals. Ultraviolet (UV) light, some infections, cigarette smoking and certain medications are among the factors being studied or associated with lupus.
- Medications: A small number of medications can cause a lupus-like condition known as drug-induced lupus. This is different from systemic lupus erythematosus and often improves after the responsible medication is discontinued.
What can trigger a lupus flare?
The factors that cause lupus to develop are not necessarily the same as those that trigger a flare once the disease is present. Flares may sometimes occur after:
- Sun or ultraviolet light exposure
- Infections
- Physical or emotional stress
- Changes in certain medications
- Stopping lupus medications without medical guidance
Sometimes a flare occurs without an identifiable trigger.
Ultimately, lupus does not have one single cause. It develops when genetic and biological susceptibility interacts with environmental influences and abnormal immune responses. Understanding these mechanisms has led to increasingly targeted treatments that address specific parts of the immune system involved in lupus.
Common symptoms of lupus
Lupus can affect many different parts of the body and symptoms vary considerably from person to person. Symptoms may develop gradually or appear more suddenly. They may also improve for periods of time and then become more active during episodes called flares.
- Persistent or unexplained fatigue
- Fever without an obvious infection
- Changes in weight or appetite
- A general feeling of being unwell
Fatigue is one of the most common symptoms of lupus and can significantly affect work, physical activity, and quality of life.
Musculoskeletal symptoms are very common and may include:
- Joint pain and tenderness
- Joint swelling
- Morning stiffness
- Muscle aches or weakness
The hands, wrists, knees and other joints are commonly affected.
Lupus can cause several skin and mucosal manifestations, including:
- Rashes that develop or worsen after sun or ultraviolet (UV) exposure
- A rash across the cheeks and bridge of the nose, sometimes called a butterfly or malar rash
- Other forms of lupus-related skin rash
- Hair thinning or hair loss
- Painless or painful sores inside the mouth or nose
Inflammation may affect the lining surrounding the lungs or heart and can cause:
- Sharp chest pain, particularly with deep breathing
- Shortness of breath
- Persistent cough in some patients
Lupus can cause inflammation of the kidneys, known as lupus nephritis. Kidney involvement may not cause noticeable symptoms early in the disease, which is why regular blood and urine testing is important.
When symptoms do occur, they may include swelling of the legs or around the eyes, foamy urine, or high blood pressure.
Lupus may affect blood cells or blood vessels and can cause:
- Anemia
- Low white blood cell or platelet counts
- Easy bruising in some patients
- Fingers or toes that change color in response to cold or stress (Raynaud phenomenon)
- An increased tendency to develop blood clots in some patients
Some people with lupus develop neurologic or cognitive symptoms which may include:
- Headaches
- Difficulty with concentration or memory
- Numbness, tingling, or other nerve symptoms
- Seizures or other neurologic manifestations in less common, more severe cases
Not everyone with lupus experiences all of these symptoms. Some people primarily have skin and joint disease, while others develop inflammation involving internal organs.
Importantly, some organ involvement, particularly kidney disease or abnormalities in blood counts, may initially cause few or no symptoms. Regular follow-up, blood testing and urine testing are therefore important even when you are feeling well.
How is lupus diagnosed?
There is no single test that can diagnose lupus. Because lupus can affect many different organs and can resemble other autoimmune, infectious and medical conditions, diagnosis requires a careful evaluation of the overall pattern of symptoms, examination findings, laboratory results and, when necessary, imaging or tissue biopsy.
A rheumatologist typically considers:
- Medical history and pattern of symptoms
- Physical examination
- Blood tests for autoantibodies and inflammation
- Blood cell counts
- Kidney and liver function
- Urine testing
- Imaging studies when specific organs are involved
- Tissue biopsy in selected situations, particularly when evaluating kidney or certain skin manifestations
Several blood tests can provide important clues:
- Antinuclear antibody (ANA): Most people with lupus have a positive ANA. However, ANA can also be positive in healthy individuals and in many other autoimmune conditions. A positive ANA by itself does not mean that a person has lupus.
- Anti-double-stranded DNA (anti-dsDNA) antibodies: These antibodies are more specific for lupus and, in some patients, may be associated with disease activity, particularly kidney involvement.
- Anti-Smith (Sm) antibodies: These antibodies are strongly associated with lupus, although they are present in only a subset of patients.
- Complement levels: Complement proteins are part of the immune system. Low levels may occur when lupus is active and can help monitor disease activity in some patients.
- Blood counts: Lupus may cause anemia or reductions in white blood cells or platelets.
- Antiphospholipid antibodies: These may be measured because some people with lupus have antibodies associated with an increased risk of blood clots and certain pregnancy complications.
Additional laboratory testing may be performed depending on your symptoms and clinical findings.
Because lupus nephritis can develop without obvious symptoms, kidney function and urine testing are an important part of both the initial evaluation and ongoing monitoring of lupus.
Testing may include:
- Kidney function blood tests
- Urinalysis to look for blood or abnormal cells
- Measurement of protein in the urine
If significant kidney involvement is suspected, a kidney biopsy may be recommended to determine the type and severity of lupus nephritis and guide treatment.
Rheumatologists do not diagnose lupus based on one abnormal laboratory result. Instead, they determine whether the overall combination of symptoms, physical findings, autoantibodies, laboratory abnormalities and organ involvement is consistent with SLE while considering other possible explanations.
Established classification criteria can help provide a standardized framework for identifying SLE, but clinical judgment remains essential for diagnosis.
Because lupus can develop gradually and its symptoms overlap with many other conditions, reaching the correct diagnosis sometimes takes time. Once lupus is diagnosed, the next important step is determining which organs are involved and how active the disease is, as this guides treatment and long-term monitoring.
How can lupus affect the body?
Lupus is a systemic autoimmune disease that can affect many parts of the body. Some people primarily have symptoms involving the joints and skin, while others may develop inflammation affecting major organs such as the kidneys, heart, lungs, brain, nervous system or blood vessels.
One of the most important complications is lupus nephritis, or inflammation of the kidneys. Kidney involvement may initially cause few or no symptoms, which is why regular blood pressure checks, blood tests, and urine testing are an important part of lupus care.
Lupus can also cause abnormalities in blood cell counts and, in some people, is associated with antiphospholipid antibodies, which may increase the risk of blood clots and certain pregnancy complications.
Because the pattern of lupus varies greatly from person to person and can change over time, regular monitoring helps identify new organ involvement early and guides treatment decisions.
How is lupus treated?
Treatment for lupus is individualized based on disease activity, severity and the organs involved. The goal is to achieve remission or low disease activity while preventing flares, protecting organs and minimizing treatment-related side effects.
Hydroxychloroquine is a cornerstone of lupus treatment and is recommended for most patients unless there is a reason it cannot be used. It can help control disease activity, reduce flares and improve long-term outcomes. Regular eye examinations are recommended during treatment.
Corticosteroids can rapidly control inflammation during lupus flares or serious organ involvement. Because long-term steroid use can cause significant side effects, the goal is to use the lowest effective dose for the shortest possible time and reduce or discontinue steroids whenever disease control allows.
For patients with persistent disease or involvement of major organs such as the kidneys, lungs, heart, or nervous system, medications that more strongly control the immune system may be needed. The choice of therapy depends on the organ involved and the severity of disease.
Newer therapies target specific immune pathways involved in lupus. These treatments have expanded the options available for patients whose disease remains active despite standard therapy and may also help reduce the need for corticosteroids.
There is no single treatment plan for everyone with lupus. Your rheumatologist will select and adjust therapy based on your disease manifestations, response to treatment, other health conditions, and individual needs.
Regular monitoring is an essential part of treatment to assess disease activity, detect organ involvement, monitor medication safety, and maintain the best possible long-term health.
Living well with lupus
Although lupus is a chronic disease, many people with lupus can lead active and fulfilling lives with appropriate treatment, preventive care and regular monitoring.
Important steps include:
- Keeping regular appointments with your rheumatologist and completing recommended blood and urine testing
- Taking medications as prescribed and discussing any concerns before stopping or changing treatment
- Protecting your skin from excessive sun and ultraviolet (UV) exposure
- Staying physically active and maintaining a balanced, heart-healthy diet
- Avoiding smoking
- Maintaining healthy sleep habits and finding effective ways to manage stress
- Staying up to date with recommended vaccinations and preventive healthcare
Because lupus can affect different organs, your rheumatologist may coordinate care with nephrology, dermatology, neurology, cardiology, pulmonology, hematology, obstetrics and gynecology or other specialists depending on your individual needs.
Learning to recognize changes in your symptoms and communicating them early to your healthcare team can help identify disease flares and complications promptly.
When should you see a rheumatologist?
Consider evaluation by a rheumatologist when symptoms or laboratory abnormalities raise concern for lupus or another systemic autoimmune disease. These may include:
- Persistent or unexplained joint pain, stiffness, or swelling
- Recurrent rashes, particularly those that worsen with sun exposure
- Unexplained fevers or persistent fatigue
- Recurrent mouth or nasal ulcers
- Unexplained hair loss
- Abnormal blood cell counts or urine tests
- Positive autoimmune blood tests accompanied by symptoms or other clinical findings
- Unexplained inflammation affecting the kidneys, lungs, heart, nervous system, or other organs
Importantly, a positive ANA test alone does not mean that you have lupus. A rheumatologist evaluates the complete pattern of symptoms, examination findings, laboratory results and organ involvement to determine whether lupus or another condition is present.
If lupus is diagnosed, your rheumatologist will help develop an individualized treatment and monitoring plan aimed at controlling disease activity, preventing organ damage, and maintaining your long-term health and quality of life.
The bottom line
Lupus is a complex systemic autoimmune disease, but effective treatments are available. Early diagnosis, appropriate treatment and regular monitoring can control inflammation, reduce flares, protect vital organs and help prevent long-term complications.
With advances in lupus care, many people can achieve remission or low disease activity and maintain active, fulfilling lives.
If you have symptoms lupus-related symptoms, or have been diagnosed with lupus and need specialized care, talk with your healthcare provider or schedule an evaluation with a UK HealthCare rheumatologist.
