Systemic Lupus Erythematosus (SLE)

Systemic lupus erythematosus is a systemic autoimmune disease commonly referred to as lupus.

Normally, the immune system protects the body from infection. In SLE, abnormal immune activity leads to the production of autoantibodies and inflammation that can damage the body’s own tissues and organs.

SLE is much more common in women, particularly during the childbearing years, but it can also affect men, children, and older adults.

The disease varies greatly between individuals. Some people mainly experience skin and joint symptoms, while others develop kidney, neurologic, lung, or blood involvement that requires more intensive treatment and monitoring.

The exact cause of SLE is not fully understood. It is thought to involve a combination of genetic susceptibility, abnormal immune regulation, hormonal influences, and environmental factors.

Factors associated with disease development or flares may include genetic susceptibility, hormonal factors, ultraviolet exposure, smoking, certain infections, and some medications.

SLE is not inherited in a simple way. Having a family member with lupus can increase susceptibility, but most relatives of patients with SLE will never develop the disease.

Ultraviolet exposure can trigger or worsen skin disease and disease activity in some patients, making sun protection an important part of long-term care.

SLE can affect many organ systems, but no patient develops every possible symptom.

Common manifestations include fatigue, low-grade fever, joint pain or swelling, skin rashes, photosensitivity, recurrent mouth or nasal ulcers, hair loss, Raynaud phenomenon, and abnormalities in red blood cells, white blood cells, or platelets.

The skin and joints are commonly affected. One well-known skin manifestation is a butterfly-shaped rash across the cheeks and bridge of the nose, although many patients with SLE never develop this rash.

Kidney involvement may cause protein or blood in the urine, swelling, high blood pressure, or impaired kidney function.

Heart and lung involvement can cause chest pain, cough, or shortness of breath and may include pleuritis or pericarditis.

Neurologic involvement can cause seizures, cognitive or psychiatric symptoms, or peripheral nerve problems, but other causes such as infection and medication effects must also be considered.

Lupus Nephritis

Lupus nephritis is one of the most important forms of organ involvement in SLE. It may initially cause no obvious symptoms, so regular urine and kidney function testing remains important even when a patient feels well.

Monitoring may include urinalysis, measurement of urinary protein, serum creatinine, and estimated glomerular filtration rate.

When persistent proteinuria, blood in the urine, declining kidney function, or other signs of nephritis are present, a kidney biopsy may be recommended. Biopsy findings help classify lupus nephritis and guide treatment. The 2025 EULAR recommendations continue to emphasize kidney biopsy as an important part of diagnosis and treatment planning.

No single test can diagnose SLE. Diagnosis requires evaluation of the overall clinical pattern together with laboratory findings and organ involvement.

Common tests include ANA, anti-double-stranded DNA antibodies, anti-Smith antibodies, complement levels, complete blood count, urine testing, kidney and liver function tests, and antiphospholipid antibodies.

ANA is an important screening marker, but a positive ANA test does not necessarily mean that a person has lupus. ANA positivity can occur in other autoimmune diseases and even in some healthy individuals.

Anti-dsDNA and anti-Smith antibodies are more specific for SLE, and changes in anti-dsDNA antibodies and complement levels may also help assess disease activity in some patients.

The widely used 2019 EULAR/ACR classification criteria use a positive ANA as an entry criterion and then assess a combination of clinical and immunologic features. Classification criteria support clinical assessment but do not replace specialist judgment.

SLE treatment is individualized according to disease activity, the organs involved, previous flares, other medical conditions, and patient-specific factors.

Modern treatment aims not only to relieve current symptoms but also to achieve long-term remission or low disease activity, prevent irreversible organ damage, and minimize treatment-related toxicity.

Hydroxychloroquine is a foundation of long-term treatment for most patients with SLE unless there is a contraindication. Regular eye monitoring is recommended during long-term use.

Glucocorticoids can rapidly control inflammation, but current treatment strategies emphasize minimizing cumulative steroid exposure. Doses should be tapered as disease control improves and withdrawn when clinically possible.

Other immunomodulatory therapies, including methotrexate, azathioprine, and mycophenolate, may be used when additional disease control is needed.

Biologic therapies such as belimumab and anifrolumab are now important options for selected patients with persistently active SLE, while rituximab may be considered in some refractory or severe organ-threatening cases.

How Is Lupus Nephritis Treated?

Treatment of lupus nephritis depends on kidney biopsy findings, the severity of proteinuria, kidney function, and other organ involvement.

For active proliferative lupus nephritis, treatment commonly includes glucocorticoids together with mycophenolate-based therapy or low-dose intravenous cyclophosphamide. Belimumab or a calcineurin inhibitor may be added in selected patients. Both KDIGO 2024 and the 2025 EULAR lupus nephritis recommendations incorporate these combination strategies into current treatment pathways.

Maintenance therapy and long-term monitoring remain important after a kidney response has been achieved.

Daily Management

Long-term SLE care includes more than medication.

Patients should use appropriate sun protection and maintain regular physical activity as their health allows.

Because SLE and some of its treatments can increase the risks of infection, osteoporosis, and cardiovascular disease, preventive care may include vaccination, bone health assessment, and management of blood pressure, cholesterol, blood sugar, and infection risk.

Patients planning pregnancy should discuss this with their rheumatology and obstetric teams in advance. Many people with well-controlled SLE can have successful pregnancies with appropriate planning and monitoring.