Paediatric lupus and vasculitis — Rapid

Synopsis

Recognise multisystem paediatric lupus and common childhood vasculitis, screen urine and blood pressure early, distinguish flare from infection and accelerate renal, neurological, pulmonary and gastrointestinal organ-threatening treatment.

Think paediatric lupus when constitutional symptoms combine with photosensitive rash, oral ulcers, alopecia, non-erosive arthritis, cytopenia, nephritis, serositis or neurological disease.
First-line tests include FBC, film, ESR, CRP, renal and liver profiles, urine dip and protein:creatinine ratio, blood pressure, C3 and C4, ANA and anti-dsDNA with targeted ENA and antiphospholipid antibodies.
ANA is sensitive but nonspecific; a positive result without a compatible multisystem phenotype does not diagnose lupus.
Urine and blood pressure are vital signs in lupus and vasculitis because renal inflammation can be silent while irreversible scarring develops.
Kidney biopsy is the reference classification test for clinically important suspected lupus nephritis and directs induction therapy.
IgA vasculitis causes non-blanching palpable purpura predominantly on legs or buttocks with abdominal pain, arthralgia or nephritis and a normal platelet count.
Check urine and blood pressure at diagnosis and through at least six months after IgA vasculitis because nephritis can appear after rash resolution.
Severe abdominal pain in IgA vasculitis needs urgent ultrasound and surgical assessment for intussusception or ischaemia; corticosteroid may treat inflammation but does not replace exclusion of surgery.
Hydroxychloroquine is background therapy for most lupus unless contraindicated; organ-threatening nephritis, brain, lung or vascular disease needs glucocorticoid plus specialist immunosuppression.
Vaccination, infection prevention, sun protection, cardiovascular and bone health, mental health, fertility and transition are core disease-modifying care.

Key red flags

Haematuria, proteinuria, oedema, hypertension or rising creatinine can be the first lupus or vasculitis organ threat and requires urgent nephrology assessment.

Haemoptysis, falling haemoglobin, hypoxia or diffuse lung infiltrates raises pulmonary capillaritis and haemorrhage even when external bleeding is absent.

Seizure, psychosis, focal deficit, severe headache or altered consciousness in lupus requires infection, thrombosis and neuroinflammatory assessment.

IgA vasculitis with severe colicky abdominal pain, guarding, gastrointestinal bleeding or bile can indicate intussusception, bowel ischaemia or perforation.

Fever in an immunosuppressed child is infection until assessed; a lupus flare and sepsis can coexist and CRP may rise disproportionately with infection.

Purpura with thrombocytopenia is not typical IgA vasculitis and broadens meningococcal disease, haematological and other vasculitic diagnoses.

Investigation priorities

First-line FBC film ESR and CRPFirst stepFirst line

Detect cytopenia, inflammation, infection clues, haemolysis and malignant mimics.

Management branches

Triage organsFind kidney brain lung and gut threats

A child has multisystem autoimmune or purpuric inflammation.

Use ABCDE and assess blood pressure, urine, renal function, brain, breathing and abdominal peritonism.
Treat sepsis and thrombosis in parallel and involve the threatened-organ specialty urgently.
Obtain targeted imaging and biopsy without delaying stabilisation or essential immune treatment.

Key medicines

HydroxychloroquineFor paediatric lupus use up to 5 mg/kg/day orally based on actual body weight, maximum 400 mg daily, adjusted by rheumatology for renal function, disease and tablet practicality.Arrange baseline eye assessment and risk-based retinal surveillance, reduce in renal impairment, review QT-prolonging combinations and monitor adherence, skin, muscle and blood-count adverse effects.

Mycophenolate mofetilFor lupus nephritis induction, a common specialist paediatric regimen is 600 mg/m² orally twice daily, usually maximum 1.5 g twice daily, then adjusted to response, tolerability and maintenance intent.Monitor FBC, liver and renal function, infection and gastrointestinal effects; it is teratogenic, requires reliable contraception and specialist pregnancy planning, and must not be stopped without nephrology review.

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