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This is a clinician-written, evidence-based summary aligned to the 2026 MLA Content Map. It is intended for medical students and junior doctors preparing for the UKMLA. Always cross-reference with NICE guidance, local protocols, and clinical judgement.
The Bottom Line
- Acute medium-vessel vasculitis in children (peak 6 months to 5 years) — leading cause of acquired heart disease in developed countries
- Diagnostic criteria: fever 5+ days PLUS 4 of 5 features: bilateral non-exudative conjunctivitis, oral changes (strawberry tongue, cracked lips), cervical lymphadenopathy (1.5+ cm, usually unilateral), polymorphous rash, extremity changes (erythema/oedema then desquamation)
- Incomplete Kawasaki: fever 5+ days with 2–3 features — still treat if supportive labs or echo
- Treatment: IVIG 2 g/kg single dose + high-dose aspirin (30–50 mg/kg/day) — within 10 days of fever onset to reduce coronary aneurysm risk from 25% to <5%
- Echocardiography at diagnosis, 2 weeks, and 6–8 weeks
- Aspirin is the ONE exception to the no aspirin in children rule
Overview
Kawasaki disease is an acute, self-limiting systemic vasculitis predominantly affecting medium-sized arteries, with a particular predilection for the coronary arteries. The aetiology remains unknown but is thought to be an abnormal immune response to an infectious trigger in genetically susceptible individuals. Without treatment, approximately 25% develop coronary artery aneurysms, which can lead to myocardial infarction, sudden death, or chronic coronary artery disease. With timely IVIG and aspirin within 10 days, this risk falls to less than 5%.
Epidemiology
Kawasaki disease is the leading cause of acquired heart disease in children in developed countries. UK incidence is approximately 8–9 per 100,000 children under 5. Most common in East Asian descent. Peak age 6 months to 5 years (80% under 5). Male:female approximately 1.5:1. Recurrence ~3%. Mortality <0.1% with treatment.
Clinical Features
Symptoms
Persistent fever 5+ days — typically high (39C+), remitting, unresponsive to antipyretics or antibiotics
Bilateral non-exudative conjunctival injection (painless, no discharge)
Oral mucosal changes: strawberry tongue, erythematous dry cracked lips
Polymorphous rash — maculopapular, targetoid, urticarial, or erythroderma. NOT vesicular
Cervical lymphadenopathy — usually unilateral, 1.5+ cm, non-suppurative
Peripheral extremity changes: erythema/oedema of hands and feet (acute), periungual desquamation (subacute)
Marked irritability — especially in infants, disproportionate to fever
Chest pain or heart failure signs (suggests myocarditis or coronary involvement)
Signs
BCG scar erythema or induration — useful early sign in vaccinated children
Perineal desquamation — may occur early
Arthritis or arthralgia
New cardiac murmur (valvular involvement or myocarditis)
Investigations
First-line
BloodsFBC (leucocytosis, thrombocytosis in week 2–3), CRP/ESR (markedly raised), LFTs (hypoalbuminaemia), blood culture (negative)
UrinalysisSterile pyuria (WBCs without bacterial growth) supports diagnosis
EchocardiogramEssential at diagnosis — coronary artery dilatation, aneurysms, pericardial effusion, LV dysfunction
Second-line
Serial echocardiogramsRepeat at 2 weeks and 6–8 weeks. More frequent if abnormalities
ECGProlonged PR, ST-T changes, arrhythmias
Specialist
CT/MR coronary angiographyFor older children or equivocal echo findings
Management
RCPCH/AHA guidelines1
First-line (within 10 days of fever onset)
- IVIG 2 g/kg as single infusion over 10–12 hours
- High-dose aspirin 30–50 mg/kg/day until afebrile for 48 h
- Then low-dose aspirin 3–5 mg/kg/day for 6–8 weeks (lifelong if coronary aneurysms)
- Treat as soon as diagnosis suspected — do not wait for day 10
2
IVIG non-responders
- If fever persists/recurs >36 h after IVIG: consider second IVIG 2 g/kg
- Refractory: IV methylprednisolone, infliximab (anti-TNF), or ciclosporin
- Risk factors for IVIG resistance: age <1 year, male, very high CRP, low albumin
3
Cardiac follow-up
- Echo at diagnosis, 2 weeks, 6–8 weeks
- If coronary abnormalities: more frequent echo, continue low-dose aspirin, possible clopidogrel or warfarin for large aneurysms
- Long-term cardiology follow-up for persistent coronary changes
4
Incomplete Kawasaki disease
- Suspect if fever 5+ days + only 2–3 features, especially in infants <6 months
- Supportive labs: CRP 30+ or ESR 40+, anaemia, leucocytosis, thrombocytosis, hypoalbuminaemia, elevated ALT, sterile pyuria
- Treat as complete Kawasaki — same coronary artery risk
Complications
- Coronary artery aneurysms: 25% without treatment, <5% with IVIG — may cause thrombosis, MI, sudden death
- Myocarditis/pericarditis: Heart failure in acute phase
- Valvular regurgitation: Mitral most common
- Macrophage activation syndrome (MAS): Rare but life-threatening
- Giant aneurysms (8+ mm): Lifelong coronary risk, long-term anticoagulation
UKMLA Exam Tips
- 1Diagnostic criteria: fever 5+ days + 4 of 5 features (conjunctivitis, oral, rash, lymphadenopathy, extremities)
- 2Aspirin in children is usually contraindicated (Reye syndrome) but Kawasaki is THE exception
- 3IVIG 2 g/kg within 10 days — reduces coronary aneurysm risk from 25% to <5%
- 4Incomplete Kawasaki: fever 5+ days + 2–3 features — still needs treatment. Think in infants with prolonged unexplained fever
- 5Thrombocytosis is a LATE feature (week 2–3) — NOT present at diagnosis
- 6BCG scar erythema is a useful exam clue
- 7Strawberry tongue is shared with scarlet fever — but Kawasaki has conjunctivitis and no tonsillar exudate
practicetest your knowledge on kawasaki diseaseApply what you've learnt with UKMLA-style questions from the iatroX Q-Bank — paediatrics and beyond.
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