Why use it

KD is diagnosed clinically — there is no specific diagnostic test. Misdiagnosis or delayed diagnosis is the primary cause of preventable coronary aneurysms in children. This tool applies the AHA 2017 criteria systematically, identifies patients meeting complete or incomplete criteria, and provides guidance on echocardiography and treatment timing. Early IVIG treatment (before day 10 of illness) prevents the majority of coronary complications.

About

Kawasaki Disease (KD) is a self-limited, acute febrile systemic vasculitis predominantly affecting children under 5 years of age. It is the most common cause of acquired heart disease in children in developed countries, primarily due to coronary artery aneurysm (CAA) formation occurring in 15–25% of untreated patients. The diagnosis is clinical, based on the presence of fever ≥5 days plus at least 4 of 5 principal clinical features. In children with fewer than 4 principal features but with coronary artery abnormalities on echocardiography, or those with prolonged fever and laboratory evidence of systemic inflammation, Incomplete (Atypical) Kawasaki Disease should be considered. The 2017 American Heart Association (AHA) scientific statement provides updated diagnostic criteria and guidance for incomplete KD. Treatment with high-dose IVIG (2 g/kg single infusion) and aspirin significantly reduces CAA risk from 25% to 3–5% if given within the first 10 days of fever.

When to use

Any child with fever ≥5 days and one or more of the classic clinical features
Infants <6 months with prolonged fever of unknown origin — high suspicion for incomplete KD
Children with fever and echocardiographic evidence of coronary artery abnormalities
Evaluation of febrile children with elevated inflammatory markers (CRP, ESR, WBC) after exclusion of bacterial/viral causes
Before initiating IVIG treatment to confirm diagnostic criteria are met or threshold for incomplete KD is reached

Formula

COMPLETE KAWASAKI DISEASE: Fever ≥5 days + ≥4 of 5 principal criteria: 1. Bilateral bulbar conjunctival injection (non-exudative) 2. Changes in lips/oral cavity: erythema/cracking of lips, strawberry tongue, or erythema of oropharynx 3. Polymorphous exanthem (rash) 4. Changes in extremities: erythema/edema of hands/feet (acute) or periungual desquamation (subacute) 5. Cervical lymphadenopathy ≥1.5 cm (usually unilateral, anterior cervical) INCOMPLETE KAWASAKI DISEASE: Fever ≥5 days + 2–3 principal criteria AND one or more of the following: • CRP ≥3 mg/dL AND/OR ESR ≥40 mm/h • Plus ≥3 supplemental laboratory criteria: - Albumin ≤3.0 g/dL - Anemia for age - ALT elevated - Platelets ≥450,000/µL (after day 7) - WBC ≥15,000/mm³ - Sterile pyuria ≥10 WBC/hpf OR echocardiographic evidence of coronary artery abnormalities (z-score ≥2.5 for LAD or RCA)

Pearls & pitfalls

Infants <6 months have the highest risk of coronary aneurysms and often present with incomplete KD — maintain a low threshold for echocardiography and IVIG in this age group.
The rash of KD is polymorphous (macular, maculopapular, urticarial, or erythema multiforme-like) — it is never vesicular or bullous. Vesicular rash makes KD very unlikely.
Perineal desquamation (around the perianal area and groin) often precedes finger-tip desquamation and may be the first clue to the diagnosis.
BCG vaccination site induration/erythema in children with recent BCG (common in Asian countries) is a highly specific finding for KD.
Uveitis (anterior) is present in up to 80% of KD patients on slit-lamp examination — though rarely clinically apparent.
IVIG must be given before day 10 of illness for maximal coronary protection. It can still be given after day 10 if fever persists or CAA detected.
Macrophage Activation Syndrome (MAS) / secondary HLH can complicate KD — suspect if ferritin markedly elevated, cytopenias, or hepatosplenomegaly out of proportion.
KD shock syndrome occurs in ~5% — these children are often older, have lower hemoglobin, higher CRP, and are more likely to be IVIG-resistant.
Giant aneurysms (z-score ≥10 or absolute diameter ≥8 mm) carry the highest long-term risk of thrombosis, stenosis, and myocardial infarction — require anticoagulation with warfarin or low-molecular-weight heparin plus aspirin.

Next steps

Complete KD (fever ≥5d + ≥4 criteria): IVIG 2 g/kg single infusion over 10–12 hours. High-dose aspirin 80–100 mg/kg/day in 4 divided doses during febrile period, then low-dose aspirin 3–5 mg/kg/day once afebrile for ≥48h for 6–8 weeks (or longer if coronary abnormalities persist). Echocardiogram at diagnosis, 2 weeks, and 6–8 weeks. Incomplete KD (meets supplemental criteria): Same treatment. IVIG-resistant KD (fever persists/recurs ≥36h after IVIG): Second dose of IVIG 2 g/kg; or infliximab 5 mg/kg IV; or methylprednisolone 30 mg/kg/day × 3 days.

Evidence

McCrindle BW et al. Diagnosis, Treatment, and Long-Term Management of Kawasaki Disease: A Scientific Statement for Health Professionals From the American Heart Association. Circulation. 2017;135(17):e927-e999. PMID:28356445. Newburger JW et al. Diagnosis, treatment, and long-term management of Kawasaki disease: a statement for health professionals from the committee on rheumatic fever, endocarditis, and Kawasaki disease. Circulation. 2004;110(17):2747-2771.

References

McCrindle BW et al. Diagnosis, Treatment, and Long-Term Management of Kawasaki Disease. Circulation. 2017;135(17):e927-e999. — link
Newburger JW et al. Diagnosis, treatment, and long-term management of Kawasaki disease. Circulation. 2004;110(17):2747-2771. — link
Kawasaki T. Acute febrile mucocutaneous syndrome with lymphoid involvement with specific desquamation of the fingers and toes in children. Arerugi. 1967;16(3):178-222. — link

Kawasaki Disease Diagnostic Criteria

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