Clinical presentation:
The diagnosis lupus can be given with a 98 % specificity and a 97 % sensitivity, if there are 4 or more of the following ACR-criteria either concurrently or within any period of time during the course of illness.
ACR-criteria (1982)/classification criteria
- Exanthema of the cheek
- Discoid exanthema
- Photosensitivity
- Oral or nasopharyngeal ulcers
- Non-erosive arthritis of the peripheral joints
- Serositis (Pleuritis or pericarditis)
- Nephropathy (Cell cylinders or proteinuria > 0,5 g/d)
- Neurological disorders in the form of cramps or psychosis
- Hematological disorders. Immune hemolytic anemia (Reticulocytosis, Coombs-test positive or leucopenia < 4000/µl or lymphopenia < 1500/µl or thrombocytopenia < 100,000/µl.
- Immunological disorders (ANA positive or DsDNA-antibodies or Sm-antibodies detectable), several more autoantibodies
- ANA positive (without evidence of medication with known ANA-inducing effect)
Basic evaluations:
ESR, CRP, blood count, urine status, creatinine-clearance, cystatin C
Immunology:
ANA (90-100 %), RF, anti-CCP, anti-ds-DNA (activity parameters), ENA (Sm 10-40 %, SS-A 25-60 %, SS-B 10-35 %, U1-RNP 30-40 %, further antibodies), cardiolipin antibodies (30-50 %) (Phospholipid antibodies), C3, C4, immune complexes.
SLE special types:
- Subacute cutaneous lupus erythematosus (SCLE): ANA, SS-A antibodies (60-100 %), SS-B antibodies (25-80 %).
- Chronic discoid lupus erythematosus (CDLE): ANA usually negative
- Neonatal lupus erythematosus (NLE): ANA mostly positive, SS-A antibodies (approximately 90 %), SS-B antibodies (approximately 70 %)
- Medication induced lupus erythematosus (mostly due to procainamide, hydralazine): ANA, ENA, histones, anti-ss-DNA (approximately 80 %)
- Congenital heart block in case of maternal SLE
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