Systemic lupus erythematosus (SLE)
Chronic autoimmune disease in which the immune system attacks the body's own tissues across multiple organ systems. Joints, skin, kidneys, blood cells, brain and heart can all be involved. 9× more common in women; usually onsets ages 15–45.
What it is
SLE is the prototype multisystem autoimmune disease. The immune system produces antibodies (most famously antinuclear antibody — ANA) against the body's own cell nuclei, forming immune complexes that deposit in tissue and trigger inflammation. The clinical picture is extraordinarily variable: any combination of fatigue, fever, joint pain, butterfly facial rash, photosensitivity, oral ulcers, hair loss, kidney inflammation (lupus nephritis), low blood counts, blood clots, pericarditis, neuropsychiatric symptoms. Prevalence is ~50 per 100,000; women are affected 9 times more than men; first symptoms usually appear between 15 and 45. The 2019 EULAR/ACR criteria are the diagnostic standard.
Key lab markers
- ANA (antinuclear antibody) — positive in >97% of SLE; required entry criterion. Negative ANA effectively rules SLE out.
- Anti-dsDNA, anti-Smith — highly specific to SLE.
- CRP, ESR — ESR usually elevated, CRP often disproportionately low; discordance can hint at SLE.
- Complement (C3, C4) — low during active disease; consumption by immune complexes.
- Creatinine, eGFR, urinalysis (proteinuria, RBC casts) — screen for lupus nephritis.
- Hemoglobin, WBC, platelets — autoimmune cytopenias common.
Symptoms
- Persistent fatigue, fever without infection
- Joint pain and morning stiffness, usually symmetric small joints
- Butterfly (malar) rash across cheeks and nose, photosensitivity
- Oral or nasal ulcers
- Raynaud's (cold fingers turning white→blue→red)
- Hair loss, sometimes patchy
- New foamy urine or leg swelling (lupus nephritis)
- Chest pain that worsens on inspiration (pleuritis / pericarditis)
- Recurrent miscarriage, blood clots (antiphospholipid antibodies)
When to discuss with a doctor
Persistent unexplained joint pain + rash + fatigue in a woman of reproductive age warrants ANA + basic immune panel. Positive ANA at >1:160 with any organ involvement should go to rheumatology; not all positive ANAs are SLE (5–10% of healthy adults have a low-titre positive). Treatment ranges from hydroxychloroquine (foundational, started in nearly everyone) to immunosuppression (mycophenolate, rituximab) for organ-threatening disease. New kidney involvement, severe cytopenia, neuropsychiatric symptoms, or pregnancy with active SLE are urgent referrals. Mediora.AI flags the lab pattern; the SLE diagnosis itself is rheumatology + criteria.