Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease in which a dysregulated immune system generates autoantibodies that attack the body's own tissues, causing inflammation and organ damage across joints, skin, kidneys, heart, lungs, blood vessels, and the central nervous system. The hallmark malar ('butterfly') rash appears across the cheeks and nose in roughly half of patients. Lupus follows an unpredictable course of flares and remissions. Women account for approximately 90 percent of cases, and the disease typically emerges during reproductive years (ages 15–45). SLE affects an estimated 1.5 million Americans, with Black women bearing the highest burden.

• Malar (butterfly) rash across the cheeks and nose, worsened by sun exposure
• Discoid rash: raised, scaly patches, more common in Black patients
• Photosensitivity (unusual skin reactions to sunlight)
• Joint pain, swelling, and morning stiffness
• Severe fatigue disproportionate to activity
• Mouth or nose sores
• Hair loss (alopecia)
• Pleuritis or pericarditis (chest pain with breathing or lying flat)
• Kidney involvement: foamy urine, swelling, elevated blood pressure
• Raynaud's phenomenon: fingers turning white or blue in cold

There is no population-level SLE screening test. The antinuclear antibody (ANA) test is useful when clinical suspicion is high but has low specificity when ordered indiscriminately — up to 20 percent of healthy individuals are ANA-positive. Specific antibodies (anti-dsDNA, anti-Sm) are more specific for SLE. Once diagnosed, regular monitoring of urine albumin-to-creatinine ratio (ACR), eGFR, CBC, and complement levels (C3, C4) guides disease activity assessment and informs treatment decisions.

Hydroxychloroquine (HCQ, Plaquenil) is the cornerstone of SLE treatment for virtually all patients — it reduces flares, organ damage accrual, and mortality. Corticosteroids manage acute flares but have significant long-term side effects. Immunosuppressants including mycophenolate mofetil (CellCept), azathioprine, and methotrexate reduce organ damage. For lupus nephritis, voclosporin (Lupkynis) and belimumab (Benlysta) are FDA-approved targeted therapies. Anifrolumab (Saphnelo) targets the interferon pathway and reduces skin and joint disease. Regular ophthalmology exams are essential for patients on long-term hydroxychloroquine due to rare retinal toxicity risk.