Systemic lupus erythematosus
Systemic lupus erythematosus is a chronic multisystem autoimmune disease in which antinuclear and other autoantibodies drive immune-complex deposition and organ injury across skin, joints, kidneys, blood, serosa, and the nervous system. Diagnosis rests on a positive antinuclear antibody plus weighted 2019 EULAR/ACR criteria totaling 10 or more points. Hydroxychloroquine is lifelong first-line therapy for nearly every patient, with glucocorticoids and steroid-sparing immunosuppression added for moderate to severe or organ-threatening disease.
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What this article covers
- Overview
Definition: systemic lupus erythematosus (SLE) is a chronic multisystem autoimmune disease in which loss of self-tolerance generates antinuclear antibodies (ANA) and other autoantibodies that form…
- Epidemiology
Sex and age: about 90% of adult patients are women; female-to-male ratio is 9:1 to 15:1 in childbearing years, narrowing to about 2:1 after menopause; incidence peaks in the third decade.
- Risk factors
Female sex during reproductive years: the dominant demographic risk factor.
- Pathophysiology
Loss of self-tolerance: defective apoptotic clearance exposes nuclear antigens, and Toll-like receptor 7 and 9 activation by immune complexes drives type I interferon-alpha production.
- Clinical features
Mucocutaneous disease in most patients: a fixed "butterfly" malar rash over the cheeks and nasal bridge that spares the nasolabial folds and flares with sun exposure; subacute lesions are…
- Differential diagnosis
Rheumatoid arthritis: symmetric small-joint polyarthritis, but erosive with positive rheumatoid factor or anti-cyclic citrullinated peptide, unlike the nonerosive, radiographically normal arthritis of SLE (rheumatoid arthritis).
- Diagnosis
The diagnosis rests on the 2019 European League Against Rheumatism/American College of Rheumatology (EULAR/ACR) classification criteria, applied clinically: a positive ANA at a titer of 1:80 or…
- Management
Start hydroxychloroquine in essentially every patient without contraindications, as lifelong background therapy: 5 mg/kg actual body weight PO daily (typically 200 to 400 mg/day), continued…
- Complications
Lupus nephritis progressing to kidney failure, the dominant driver of morbidity; 10% to 30% of biopsy-proven nephritis reaches end-stage kidney disease within 15 years despite treatment (lupus nephritis).
- Prognosis
Improved but still shortened survival: 5-year survival is about 90%, though mortality remains elevated versus age-matched controls.
- Prevention
Maintain hydroxychloroquine at 5 mg/kg/day or less, with a baseline dilated retinal exam within the first year and annual screening from year 5, sooner with renal impairment or higher dosing.
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