Systemic lupus erythematosus — Rapid

Synopsis

Recognise the multisystem patterns of systemic lupus erythematosus, measure activity and accumulated damage separately, screen organs proactively, and select proportionate treatment with infection and reproductive safety built into every decision.

Suspect SLE when inflammatory joint disease, photosensitive or subacute cutaneous rash, oral or nasal ulcers, alopecia, serositis, cytopenia, renal abnormality or neurological disease occur in a coherent multisystem pattern.
ANA is a sensitive entry test but is not specific and must not be used as a population screen for non-specific fatigue or pain; a negative result makes ordinary SLE less likely but does not replace specialist judgement.
When the phenotype supports lupus, define anti-dsDNA, anti-Sm, C3 and C4, FBC, renal and liver function, urinalysis and quantitative protein, and test antiphospholipid, anti-Ro and anti-La antibodies for their distinct consequences.
At every review, check blood pressure, urine, creatinine, blood count, symptoms and treatment adherence; clinically silent nephritis is missed if urine is tested only after oedema appears.
Continue hydroxychloroquine for most people unless contraindicated, using no more than 5 mg/kg actual body weight daily and arranging retinal monitoring according to dose, duration and kidney risk.
Match immunosuppression to the organ and severity: topical measures or steroid-sparing conventional therapy may control skin and joints, whereas renal, neurological, pulmonary or haematological disease needs rapid specialist combination treatment.
A rise in anti-dsDNA or fall in complement can support activity but neither alone proves a flare or justifies treatment escalation; integrate examination, organ measures, infection assessment and trend.
Plan pregnancy while disease is quiet on compatible medicines; continue hydroxychloroquine, identify antiphospholipid and anti-Ro or anti-La antibodies, and replace methotrexate, mycophenolate or cyclophosphamide before conception under specialist care.
Avoid using long-term oral glucocorticoid as maintenance by default; cumulative exposure drives infection, diabetes, cataract, cardiovascular disease, avascular necrosis and osteoporosis.
Distinguish reversible inflammatory activity from accumulated damage, infection, fibromyalgia and medicine toxicity before increasing immunosuppression.

Key red flags

Fever with hypotension, neutropenia, immunosuppression or a focal source requires immediate sepsis assessment even when lupus activity is also plausible.

Haemoptysis, falling haemoglobin and new diffuse infiltrates may indicate pulmonary haemorrhage and need emergency respiratory, renal and rheumatology care.

New proteinuria, glomerular haematuria, casts, hypertension or rising creatinine requires urgent lupus-nephritis assessment rather than routine follow-up.

Seizure, psychosis, transverse myelitis, mononeuritis multiplex or focal deficit requires urgent neurological investigation for inflammatory, thrombotic, infectious and metabolic causes.

Chest pain, troponin rise, arrhythmia, heart failure or tamponade physiology requires acute cardiac assessment rather than attribution to benign serositis.

Renal warning pattern

Hypertension, proteinuria, dysmorphic haematuria, casts or creatinine change may be the only evidence of nephritis and requires urgent combined review.

Neuropsychiatric disease

Seizure, psychosis, cognitive change, headache, neuropathy or stroke requires cause-specific investigation because lupus, APS, infection and metabolic disease overlap.

Investigation priorities

ANA by validated assayFirst step

Support diagnostic assessment when the clinical pre-test probability is meaningful.

Management branches

First assessmentBuild a clinical and organ map

Multisystem inflammatory features raise a credible suspicion of systemic lupus erythematosus.

Document chronology, objective skin and joint findings, serosal, neurological, renal, obstetric and thrombotic history, medicines, infections and family history.
Request ANA with FBC, renal and liver profile, ESR or CRP, blood pressure and urine assessment; add specific antibodies and complements when the phenotype remains compatible.
Refer to rheumatology, urgently when an organ is threatened, while directing acute kidney, neurological, cardiac, pulmonary, thrombotic or infection care in parallel.

Preferred background treatmentUse hydroxychloroquine with prevention

SLE is confirmed and no contraindication prevents antimalarial treatment.

Record actual body weight, eGFR, interacting medicines, ocular history and baseline examination requirements before selecting a dose no higher than 5 mg/kg/day.
Combine treatment with UV avoidance, smoking cessation, immunisation, cardiovascular and bone protection, reproductive planning and clear flare or infection advice.
Assess adherence and toxicity at review; a low drug exposure from missed doses should not be mislabelled refractory disease.

Key medicines

HydroxychloroquineUsually 200–400 mg orally once daily with food, using the lowest effective dose and not exceeding 5 mg/kg actual body weight per day; reduce exposure when kidney function or other toxicity risk requires it.Avoid in established maculopathy, review QT-prolonging combinations, cardiomyopathy, hypoglycaemia and renal impairment, and arrange retinal monitoring after five years or after one year when high risk. It is compatible with pregnancy and breastfeeding under BSR guidance.

AzathioprineSpecialist oral dosing is commonly started at 25–50 mg daily and increased toward 1–2 mg/kg/day according to TPMT status, response and blood monitoring.Check TPMT, FBC, liver and renal function and infection status; allopurinol or febuxostat interactions require expert dose adjustment or avoidance. Monitor cytopenia, hepatitis and pancreatitis. BSR regards doses no greater than 2 mg/kg/day as compatible with pregnancy.

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