Kawasaki Disease

Clinically reviewed Aug 29, 2026 Updated Aug 30, 2026

Clinical Snapshot

Kawasaki disease (KD) is an acute, self-limited but potentially serious systemic vasculitis of small- and medium-sized arteries, of unknown cause, that predominantly affects young children — most commonly those under 5 years of age — and can occur throughout childhood.[1] It is a leading cause of acquired heart disease in children in Canada, a status it holds specifically because of its particular predilection for the coronary arteries: coronary artery aneurysm formation is the source of essentially all serious long-term morbidity and, rarely, mortality from this disease, and preventing it is the central organizing goal of every intervention described in this chapter.[1]

The diagnostic backbone: fever plus 4 of 5 principal features. Kawasaki disease is diagnosed clinically. The required core feature is fever for at least 5 days, together with at least 4 of 5 principal clinical features — bilateral non-exudative conjunctival injection, oral mucous membrane changes, a polymorphous rash, extremity changes, and cervical lymphadenopathy. See Recognize the Condition for the full criteria table, including the important incomplete/atypical presentation that is especially common — and especially dangerous to miss — in infants under 6 months.[1]

Left untreated, roughly 25% of children with Kawasaki disease develop coronary artery aneurysms.[2] The single most important treatment goal is to reduce that risk: intravenous immunoglobulin (IVIG), given ideally within the first 10 days of fever onset, reduces the aneurysm risk to under 5% — making timely recognition and treatment, more than any other factor, the central clinical priority in this chapter.[1] Acute-phase treatment pairs IVIG with aspirin — an anti-inflammatory, higher dose during the febrile phase, transitioning to a low, antiplatelet dose once fever resolves — a deliberate, guideline-endorsed exception to the usual pediatric avoidance of aspirin due to Reye syndrome, addressed explicitly in Common Errors to Avoid.[1] Patients at higher risk of IVIG resistance, or with IVIG-refractory disease, may receive adjunctive corticosteroids or the biologic infliximab; long-term management is then stratified by the severity of any coronary artery involvement found on echocardiography.[3]

Recognize the Condition

Epidemiology

In Canada, the incidence of Kawasaki disease is highest in preschoolers, at 19.6 to 26.0 cases per 100,000 children under age 5, and it represents a leading cause of acquired childhood heart disease nationally.[1] The cause remains unknown; a triggering infection or environmental exposure in a genetically susceptible child is suspected, but no single causative organism has been identified.[1]

The classic diagnostic criteria — complete Kawasaki disease

Complete (classic) Kawasaki disease is diagnosed by fever for at least 5 days plus at least 4 of the 5 principal clinical features below; diagnosis can be made as early as day 4 of fever if 4 or more principal features are already present.[1]

Required core featureDescription
FeverPresent for at least 5 days (diagnosis may be made on day 4 if ≥4 principal features are already present)
Principal clinical feature (≥4 of 5 required)Description
Bilateral conjunctival injectionNon-exudative (non-purulent), typically with perilimbal sparing — see photograph below
Oral mucous membrane changesStrawberry tongue, and red, cracked, swollen lips — see photograph below
Polymorphous rashVariable morphology; typically truncal, non-vesicular
Extremity changesErythema and edema of the palms/soles in the acute phase; periungual desquamation in the subacute phase (roughly 2-3 weeks after fever onset) — see photograph below
Cervical lymphadenopathyAt least 1.5 cm, typically unilateral — usually the least consistently present of the 5 features

[1]

Bilateral non-exudative conjunctival injection with perilimbal sparing in a child with Kawasaki disease
Bilateral, non-exudative conjunctival injection with perilimbal sparing — one of the 5 principal clinical features. Image: Dong Soo Kim, CC BY 2.0, via Wikimedia Commons.
Strawberry tongue and red, swollen, cracked lips in a child with Kawasaki disease
Strawberry tongue with bright red, swollen lips showing vertical cracking — the classic oral mucous membrane change. Image: Dong Soo Kim, CC BY 2.0, via Wikimedia Commons.
Erythema of the palms with edema of the hands in a child with Kawasaki disease
Erythema of the palms with painful, brawny edema of the dorsa of the hands — the acute-phase extremity change; periungual desquamation follows in the subacute phase. Image: Dong Soo Kim, CC BY 2.0, via Wikimedia Commons.

Incomplete (atypical) Kawasaki disease — a genuinely important and clinically tricky variant

Fewer classic features does not mean lower risk — often the opposite. Incomplete/atypical Kawasaki disease is defined as fever for at least 7 days in infants under 12 months, OR fever for at least 5 days with only 2-3 principal features, together with elevated inflammatory markers (ESR ≥40 mm/h or CRP ≥30 mg/L) and either supportive echocardiographic findings or at least 3 of 6 supplemental laboratory criteria.[1] This presentation is more common in infants under 6 months — and these same infants are at higher risk of coronary artery complications despite the less classic clinical picture: patients age ≤6 months (or with a coronary artery Z-score ≥2.5 at diagnosis) carry an approximately 16-fold increased likelihood of coronary artery aneurysm development.[3] This is precisely the group most likely to be missed or diagnosed late, exactly when they are at greatest risk — maintain a high index of suspicion for prolonged, unexplained fever in a young infant even when fewer than 4 principal features are present.[1][3]

Risk Factors

  • Age under 5 years — the incidence peaks in preschoolers, at 19.6-26.0 cases per 100,000 children under age 5 in Canada.[1]
  • Age under 12 months, and particularly under 6 months — the highest-risk group both for an incomplete/atypical presentation and, independently, for coronary artery aneurysm development (an approximately 16-fold increased risk versus older children).[3]
  • No single causative organism or environmental exposure has been confirmed; a preceding infectious or environmental trigger in a genetically susceptible child is suspected but not established, and Kawasaki disease is not considered contagious.[1]
  • A coronary artery Z-score of 2.5 or higher already present at diagnosis independently identifies a higher-risk group regardless of age.[3]
  • Male sex and East Asian ancestry are recognized epidemiologic associations in the broader international literature, though this chapter's Canadian incidence figures reflect the general Canadian pediatric population.[1]

Red Flags & Refer

This entire chapter is fundamentally about timely recognition — prolonged, unexplained fever in a young child should prompt consideration of Kawasaki disease rather than being dismissed as a routine viral illness. Refer promptly for pediatric (or pediatric cardiology/emergency) evaluation for:

  • Fever for 5 or more days (7 or more days in an infant under 12 months) without a clear alternative explanation, particularly with any of the 5 principal clinical features present — even if fewer than 4 are present, especially in an infant under 6 months (see Recognize the Condition for incomplete/atypical Kawasaki disease).[1]
  • Any suspected case — do not wait for echocardiography or laboratory confirmation before arranging urgent assessment; echocardiography should never delay treatment once the clinical picture is convincing.[1]
  • IVIG resistance — persistent or recrudescent fever 24-36 hours or more after completing an IVIG infusion — which requires prompt reassessment and second-line therapy rather than simply waiting it out (see Treatment Failure/Next Step).[1]
  • Signs suggesting Kawasaki disease shock syndrome or macrophage activation syndrome (hypotension, poor perfusion, or a markedly more severe/atypical illness course) — these require urgent escalation and specialist-directed intensified therapy (see Special Populations).[1]
  • New or worsening cardiac symptoms in a child with a known coronary artery aneurysm (chest pain, syncope, pallor, or irritability with diaphoresis in a young child, which can represent myocardial ischemia) — evaluate emergently.[3]

The pharmacist's role here is recognition and prompt escalation, not outpatient reassurance — the aneurysm-prevention benefit of treatment is time-dependent, and delay has a real, measurable cost.[1]

Assessment & Diagnosis

Kawasaki disease is a clinical diagnosis, supported by labs and echocardiography

Diagnosis rests primarily on the fever-plus-principal-features pattern described in Recognize the Condition. Laboratory testing and echocardiography support the diagnosis — particularly for incomplete/atypical presentations — and guide risk stratification, but should not delay treatment once the clinical picture is convincing.[1]

Laboratory findings

No single laboratory test is diagnostic. Supportive findings include elevated inflammatory markers (ESR ≥40 mm/h, CRP ≥30 mg/L), which are used both to support the diagnosis of incomplete Kawasaki disease and to help confirm the incomplete-KD supplemental laboratory criteria (which also include anemia for age, a white blood cell count ≥15,000/mm³, sterile pyuria, elevated ALT, low albumin, and a platelet count ≥450,000/mm³ after day 7 of illness).[1] Thrombocytosis is a particularly characteristic finding in the subacute phase — the platelet count is usually normal in the first several days of illness and rises, sometimes markedly, as the acute inflammation begins to resolve, typically in the second or third week.[1]

Echocardiography — obtain it, but never let it delay treatment

Echocardiography at diagnosis is essential for assessing coronary artery involvement using standardized Z-score calculations, but should never delay initiation of therapy in a clinically convincing presentation.[1] Coronary artery aneurysms can continue to develop for up to 4 to 6 weeks after disease onset, which is why serial follow-up echocardiography (not a single study at diagnosis alone) is essential — see Monitoring & Follow-Up for the specific schedule.[1]

Coronary artery Z-score categoryDefinition
No involvementZ-score always <2
Dilatation onlyZ-score ≥2 to <2.5
Small aneurysmZ-score ≥2.5 to <5
Medium aneurysmZ-score ≥5 to <10
Large/giant aneurysmZ-score ≥10, or an absolute internal diameter ≥8 mm

Cardiac prognosis worsens with increasing coronary artery size; this classification directly determines the long-term antithrombotic strategy described in Monitoring & Follow-Up.[1][3]

Differential diagnosis

Consider and exclude alternative explanations for prolonged fever with a mucocutaneous/rash picture, particularly measles, scarlet fever, staphylococcal or streptococcal toxin-mediated illness (toxic shock syndrome), drug hypersensitivity reactions, juvenile idiopathic arthritis, and — in the appropriate epidemiologic context — multisystem inflammatory syndrome in children (MIS-C). A clear alternative diagnosis with a typical course argues against Kawasaki disease, but persistent or atypical fever should prompt reassessment rather than premature closure.[1]

Treatment Targets

  • Reduce systemic inflammation during the acute febrile phase.
  • Reduce the risk of coronary artery aneurysm formation — the single most important treatment goal, since this is the complication that drives essentially all long-term cardiac morbidity, and rarely mortality, from this disease.[1]
  • Treat within the defined early time window from fever onset (ideally within the first 10 days) to maximize the aneurysm-risk reduction achievable with IVIG.[1]
  • Identify patients at higher risk of IVIG resistance or more severe disease early, so that adjunctive therapy can be added up front rather than only after resistance has already occurred.[3]
  • Prevent thrombosis in any coronary artery abnormality that does develop, with antiplatelet or, where indicated, anticoagulant therapy matched to aneurysm severity.
  • Support the family through an acute, frightening illness and its monitoring requirements with clear, honest education — including specifically addressing aspirin/Reye syndrome concerns (see Common Errors to Avoid).

Choose Initial Treatment

Direct treatment rule

IVIG plus aspirin — the central acute pharmacotherapy

Every confirmed or strongly suspected case: give IVIG 2 g/kg as a single IV infusion, ideally within the first 10 days of fever onset — earlier treatment is more effective at preventing coronary complications, a genuinely time-critical point. Treatment given after day 10 is still beneficial if fever, inflammation, or aneurysm formation is ongoing, and should not be withheld solely because the 10-day window has passed.[1]

Pair IVIG with aspirin at an anti-inflammatory dose during the acute febrile phase — either 30-50 mg/kg/day PO divided every 6 hours (up to 80-100 mg/kg/day in some protocols), or low-dose aspirin from the outset; both approaches are currently accepted.[1]

The high-dose-to-low-dose aspirin transition — a specific and important protocol detail

Once the child has been afebrile for 24-48 hours and inflammatory markers are improving, transition aspirin from the anti-inflammatory dose to a low, antiplatelet dose of 3-5 mg/kg PO once daily, continued for a minimum of 4-6 weeks or longer if any coronary artery abnormality is identified.[1]

A deliberate exception to routine pediatric aspirin avoidance. Aspirin is normally avoided in febrile children because of the risk of Reye syndrome, particularly during varicella or influenza infection. Its use in Kawasaki disease is a specific, guideline-endorsed exception to that rule — not an oversight — and pharmacists should be prepared to explain this proactively, since it is a common point of parent/caregiver concern and even occasional prescriber hesitation. Monitor for concurrent varicella or influenza during the low-dose maintenance phase and switch to an alternative antiplatelet (clopidogrel or dipyridamole) if either occurs; children on long-term aspirin should also receive annual influenza vaccination.[1]

Adjunctive corticosteroids for higher-risk patients

For patients identified as being at higher risk of IVIG resistance by current risk-scoring approaches, or for IVIG-refractory disease, add an adjunctive corticosteroid: oral prednisone/prednisolone 2 mg/kg/day (maximum 60 mg/day), used consultatively and tapered per specialist direction, is the typical approach for up-front intensification or IVIG resistance; IV methylprednisolone 30 mg/kg (maximum 1000 mg/dose) is reserved specifically for the more severe presentations of Kawasaki disease shock syndrome or macrophage activation syndrome.[1] In this higher-risk/IVIG-resistant group, adding either a corticosteroid or infliximab reduces progression of coronary artery aneurysm size compared with IVIG alone — the evidence suggests that using one of the two matters more than which specific agent is chosen.[3]

Biologic and second-line options for IVIG-resistant disease

Infliximab is a well-established second-line option, alongside a second dose of IVIG or corticosteroids, for patients with IVIG-refractory disease — see Treatment Failure/Next Step for the full escalation pathway.[1][3]

Non-Pharmacologic Treatment

  • Admit every patient with confirmed or strongly suspected Kawasaki disease for IVIG administration, monitoring, and baseline echocardiography.[1]
  • Supportive care during the acute febrile phase: adequate hydration, and antipyresis with acetaminophen as needed alongside the anti-inflammatory aspirin dose.
  • Confirm the child has been afebrile for at least 24-48 hours and is clinically improving before considering discharge, and confirm the aspirin dose has been (or is ready to be) transitioned to the low, antiplatelet dose.[1]
  • Arrange the full serial echocardiography follow-up schedule before discharge — do not leave this to be arranged later (see Monitoring & Follow-Up).[1]
  • Provide clear caregiver education before discharge: the deliberate, guideline-endorsed reason for using aspirin in this specific illness despite the usual Reye syndrome caution; the specific signs of varicella or influenza that should prompt a call and a switch to an alternative antiplatelet; the specific signs of IVIG resistance (recurring or persisting fever) that should prompt prompt reassessment rather than a wait-and-see approach; and, for any child found to have a coronary artery abnormality, honest counseling about the long-term follow-up and antithrombotic therapy that will be needed.[1]
  • Defer live-virus vaccines (e.g. measles-mumps-rubella, varicella) for 11 months after high-dose IVIG, since IVIG can blunt the immune response to live vaccines; inactivated vaccines, including seasonal influenza vaccine, can proceed on the usual schedule and are specifically recommended for children remaining on long-term aspirin.[1]
  • Involve pediatric cardiology early and continuously in any child with coronary artery involvement, and arrange psychological support for families navigating a frightening acute illness and, where relevant, an ongoing cardiac diagnosis.

Pharmacologic Treatment Options

Drug / interventionRoleDose / useImportant adverse effectsTeaching points
Immunoglobulin (Human) — IVIG
Preferred
First-line disease-modifying therapy for every confirmed or strongly suspected case2 g/kg IV as a single infusion, ideally within the first 10 days of fever onsetAseptic meningitis, hemolytic anemia, anaphylaxis in IgA-deficient patients, rare acute kidney injuryEarlier treatment substantially reduces coronary artery aneurysm risk (to under 5%) — do not delay for confirmatory testing
Acetylsalicylic acid (ASA) — acute (anti-inflammatory) dosing
Preferred
Anti-inflammatory dosing paired with IVIG during the acute febrile phase30-50 mg/kg/day PO divided every 6 hours (up to 80-100 mg/kg/day in some protocols) until afebrileGI upset, rare hepatotoxicity, tinnitus at high dosesA deliberate, guideline-endorsed exception to routine pediatric aspirin avoidance for this specific indication — see Common Errors to Avoid
Acetylsalicylic acid (ASA) — maintenance (antiplatelet) dosing
Preferred
Low-dose antiplatelet dosing once the child is afebrile and inflammatory markers are improving3-5 mg/kg PO once daily; continue for a minimum of 4-6 weeks, or longer if coronary abnormalities are presentGI upset, bleeding riskSwitch to clopidogrel or dipyridamole if the child develops varicella or influenza while on this dose
Prednisone/prednisolone
Alternative
Adjunctive therapy for patients at higher risk of IVIG resistance, or added for IVIG-refractory disease2 mg/kg/day PO (maximum 60 mg/day), tapered per specialist directionHyperglycemia, mood changes, GI upset, immunosuppressionChoosing a corticosteroid or infliximab in this higher-risk group reduces coronary aneurysm progression versus IVIG alone
Methylprednisolone (IV pulse)
Alternative
Reserved for Kawasaki disease shock syndrome or macrophage activation syndrome30 mg/kg IV (maximum 1000 mg/dose)Hyperglycemia, hypertension, GI bleeding, adrenal suppression with repeated dosingFor the most severe/atypical presentations, not routine adjunctive use
Infliximab
Alternative
Second-line biologic for IVIG-resistant/refractory disease5 mg/kg IV single infusion, specialist-directedInfusion reactions, infection risk, rare hepatotoxicityAn alternative to a second IVIG dose or corticosteroids for IVIG-resistant disease — choice among second-line options is specialist-directed
Clopidogrel
Alternative
Antiplatelet alternative to ASA when ASA is contraindicated or during intercurrent varicella/influenza1 mg/kg/day PO (maximum 75 mg/day), specialist-directedBleeding, GI upset, rare thrombocytopeniaA reasonable substitute for low-dose ASA specifically when Reye syndrome risk factors are present
Warfarin
Alternative
Anticoagulation added to antiplatelet therapy for large/giant coronary aneurysmsSpecialist-directed, titrated to INR targetBleeding, requires frequent monitoring, numerous drug/food interactionsReserved for large/giant aneurysms (Z-score ≥10) — see Monitoring & Follow-Up for the full risk-stratified approach

Special Populations

Infants under 6 months

The single most important special population in this chapter. Infants under 6 months are more likely to present with incomplete/atypical Kawasaki disease (fewer than 4 principal features), yet carry an approximately 16-fold higher risk of coronary artery aneurysm development than older children.[3] This combination — a less classic presentation in the group at greatest risk — is precisely why these infants are more likely to be missed or diagnosed late. Maintain a low threshold to investigate prolonged, unexplained fever in this age group even without 4 principal features, and use the incomplete-KD criteria (fever ≥7 days plus elevated inflammatory markers and supportive echo/lab criteria) rather than waiting for a more classic picture to emerge.[1][3]

Kawasaki disease shock syndrome and macrophage activation syndrome

A minority of patients present with, or develop, a more severe, atypical course marked by hypotension and poor perfusion (Kawasaki disease shock syndrome) or hyperinflammatory macrophage activation syndrome. These patients require urgent escalation, intensive supportive care, and IV pulse methylprednisolone (see Choose Initial Treatment) rather than standard-dose adjunctive therapy alone.[1]

IgA deficiency

As with any IVIG indication, anaphylaxis is a recognized risk in patients with known IgA deficiency; screen where feasible and have the treating team plan accordingly.

Vaccination timing

Defer live-virus vaccines for 11 months after high-dose IVIG, since the antibody load can blunt the vaccine immune response; inactivated vaccines, including seasonal influenza vaccine, are not affected and influenza vaccination is specifically recommended for children remaining on long-term aspirin.[1]

Renal and hepatic considerations

Use IVIG cautiously in renal impairment, favouring a non-sucrose formulation and adequate hydration where feasible, consistent with IVIG use in any other indication. Aspirin should be used cautiously, with attention to bleeding risk and GI tolerability, in any child with a bleeding diathesis or significant hepatic impairment; there is no specific Kawasaki-disease-specific dose adjustment beyond standard pediatric practice.

Monitoring & Follow-Up

Echocardiography follow-up schedule

Obtain a baseline echocardiogram at diagnosis, without delaying treatment to do so, then repeat at 2 weeks and again at 4-6 weeks after disease onset, since aneurysms can continue to develop for up to 4-6 weeks.[1] In patients identified as high-risk (age ≤6 months, or a coronary artery Z-score ≥2.5 at diagnosis), repeat the echocardiogram again 2-3 days after the first study even if it was normal, and arrange outpatient follow-up at 1 week rather than the standard 1-2 week interval.[3]

Long-term management, stratified by coronary artery involvement

  • No or minimal involvement (Z-score consistently <2.5) confirmed on follow-up echocardiography at 6-8 weeks: discontinue low-dose aspirin at that point and no further cardiology follow-up is generally needed.[1]
  • Small-to-medium aneurysms (Z-score 2.5 to <10): continue low-dose aspirin long-term and maintain periodic cardiology follow-up. Small-to-moderate aneurysms typically regress within 1 year, though 1.5-3% of patients experience recurrent disease within 12 months.[1]
  • Large/giant aneurysms (Z-score ≥10, or ≥8 mm absolute diameter): add anticoagulation — warfarin, a low-molecular-weight heparin, or a direct oral anticoagulant (DOAC) — to ongoing antiplatelet therapy, with long-term specialized cardiology follow-up; this is the highest-risk group for coronary thrombosis and long-term cardiac morbidity. A DOAC offers reduced monitoring requirements and fewer drug/food interactions than warfarin, where appropriate.[3] For a medium aneurysm where a documented thrombus has regressed, continuing anticoagulation rather than switching to antiplatelet therapy alone is a reasonable specialist-directed approach.[3]

Complications

Coronary artery aneurysm formation is the central complication of this disease, with the long-term risks of thrombosis, myocardial infarction, and (rarely) sudden cardiac death rising with aneurysm size, particularly for large/giant aneurysms.[3] Other recognized acute-phase complications include myocarditis, valvular regurgitation, and, uncommonly, Kawasaki disease shock syndrome or macrophage activation syndrome (see Special Populations). Most children with no or minimal coronary involvement have an excellent long-term prognosis.[1]

Treatment Failure / Next Step

  1. IVIG resistance — persistent or recrudescent (recurring) fever 24-36 hours or more after completing an IVIG infusion — affects approximately 10-20% of patients and requires prompt reassessment rather than a wait-and-see approach.[1]
  2. First-line escalation options for IVIG-resistant disease include a repeat dose of IVIG, a corticosteroid (oral prednisone/prednisolone or, for more severe presentations, IV methylprednisolone), or infliximab; the specific choice is specialist-directed, since current evidence suggests using one of these matters more than which one is chosen.[1][3]
  3. Further-line options for refractory disease, particularly where hemoglobin has dropped more than 20 g/L after the first IVIG dose, include anakinra; additional options described in the current American literature include etanercept and cyclosporine.[1][3]
  4. Persistent shock, hypotension, or a markedly more severe course despite escalation: reconsider and evaluate for Kawasaki disease shock syndrome or macrophage activation syndrome, and escalate to intensive/critical care.[1]
  5. An evolving or new coronary artery abnormality on any follow-up echocardiogram: escalate the antithrombotic strategy per the Z-score-based tiers in Monitoring & Follow-Up rather than continuing the prior aspirin-only plan unchanged.[3]
  6. Diagnostic uncertainty at any stage, including a atypical or non-classic course: reconsider alternative diagnoses (see Assessment & Diagnosis) rather than continuing to treat empirically as Kawasaki disease indefinitely.

Common Errors to Avoid

  • Withholding aspirin in a child with Kawasaki disease out of a general Reye-syndrome-related reflex against pediatric aspirin use — this is a specific, deliberate, guideline-endorsed exception, not an oversight, and should be explained proactively to concerned caregivers and, where needed, to hesitant prescribers.[1]
  • Dismissing prolonged, unexplained fever in a young child — especially an infant under 6 months — as a routine viral illness without considering Kawasaki disease, particularly when fewer than 4 principal features are present; this is exactly the presentation most likely to be missed in the group at highest coronary risk.[1][3]
  • Waiting for echocardiographic or laboratory confirmation before initiating IVIG in a clinically convincing presentation — treatment timing from fever onset is directly tied to aneurysm-risk reduction.[1]
  • Forgetting to transition aspirin from the high, anti-inflammatory dose to the low, antiplatelet dose once the child becomes afebrile — continuing high-dose aspirin unnecessarily increases bleeding and GI risk without added benefit at that stage.[1]
  • Treating a recurring or persisting fever after IVIG as simply "the same illness continuing" rather than recognizing it as IVIG resistance requiring prompt reassessment and second-line therapy.[1]
  • Discontinuing low-dose aspirin, or relaxing echocardiography follow-up, before the full 4-6 week (or longer, if abnormalities are found) monitoring schedule is complete.[1]
  • Giving a live-virus vaccine too soon after high-dose IVIG, which can blunt the vaccine response — defer for 11 months; inactivated vaccines, including influenza vaccine, are not affected.[1]
  • Underestimating the long-term risk in large/giant coronary artery aneurysms, or failing to add anticoagulation to antiplatelet therapy when the Z-score threshold is met.[3]

Clinical Decision Algorithm

Algorithm A — Recognition and diagnostic pathway
Fever in a young child, especially prolonged or unexplained (≥ 5 days; ≥ 7 days in an infant under 12 months)
Screen for the 5 principal clinical features: bilateral non-exudative conjunctival injection, oral mucous membrane changes (strawberry tongue / red cracked lips), polymorphous rash, extremity changes (erythema/edema acute, periungual desquamation subacute), cervical lymphadenopathy ≥ 1.5 cm[1]
Fever ≥ 5 days plus ≥ 4 of 5 features (or ≥ 4 features present by day 4)
Complete Kawasaki disease — proceed to Algorithm B (treatment) without delay[1]
Fever ≥ 5 days with only 2-3 features, or fever ≥ 7 days in an infant under 12 months, plus elevated inflammatory markers
Incomplete/atypical Kawasaki disease — obtain echocardiography and supplemental labs. Infants under 6 months are at HIGHER coronary risk despite the less classic presentation — do not let an atypical picture lower suspicion[1][3]
Meets echo findings or ≥ 3 of 6 supplemental laboratory criteria — treat as confirmed Kawasaki disease, proceed to Algorithm B[1]
A clear alternative explanation is identified (e.g. classic viral exanthem, streptococcal infection, drug reaction)
Reconsider the diagnosis; reassess promptly if fever persists or new principal features develop
Algorithm B — Acute pharmacotherapy
Confirmed or strongly suspected Kawasaki disease
IVIG 2 g/kg IV as a single infusion, ideally within the first 10 days of fever onset — earlier treatment reduces coronary aneurysm risk from ~25% (untreated) to under 5%[1][2]
Aspirin at anti-inflammatory dosing (30-50 mg/kg/day, divided every 6 hours) during the acute febrile phase[1]
Higher risk of IVIG resistance, or already IVIG-refractory
Add an adjunctive corticosteroid (prednisone/prednisolone, or IV methylprednisolone for shock/MAS) or consider infliximab — either reduces coronary aneurysm progression versus IVIG alone in this group[3]
Standard risk
IVIG plus acute-phase aspirin alone
Once afebrile for 24-48 hours and inflammatory markers improving: transition aspirin from high dose to LOW dose (3-5 mg/kg once daily, antiplatelet) — continue for at least 4-6 weeks[1]
Persistent or recrudescent fever ≥ 24-36 hours after completing IVIG = IVIG resistance — do NOT simply wait; reassess and escalate per Treatment Failure/Next Step[1]
Proceed to Algorithm C for coronary artery monitoring and long-term management
Algorithm C — Coronary artery monitoring and risk-stratified long-term management
Baseline echocardiogram at diagnosis — obtain it, but never let it delay IVIG/aspirin treatment[1]
Repeat echocardiogram at 2 weeks and again at 4-6 weeks. High-risk patients (age ≤ 6 months, or Z-score ≥ 2.5 at diagnosis): repeat again 2-3 days after the first study and arrange 1-week outpatient follow-up[1][3]
No/minimal involvement (Z-score consistently < 2.5) at 6-8 week follow-up
Discontinue low-dose aspirin; no further cardiology follow-up generally needed[1]
Small-to-medium aneurysm (Z-score 2.5 to < 10)
Continue low-dose aspirin long-term with periodic cardiology follow-up — most regress within 1 year, but 1.5-3% recur within 12 months[1]
Large/giant aneurysm (Z-score ≥ 10, or ≥ 8 mm absolute diameter)
Add anticoagulation (warfarin, LMWH, or a DOAC) to antiplatelet therapy; long-term specialized cardiology follow-up — the highest-risk group for thrombosis and long-term cardiac morbidity[3]

Drug Tables

How to use this table: Doses are adult doses and require patient-specific confirmation (renal/hepatic function, weight, allergy history). Pediatric dosing is weight-based per the current product monograph unless stated. Drug pricing is intentionally omitted. Select any drug name to open its complete Pharmasist Drug Database page.

Disease-Modifying Acute Therapy

The essential acute pharmacotherapy for every confirmed or strongly suspected case — start as early as possible, ideally within 10 days of fever onset.

DrugDosageAdverse effectsDrug interactionsComments
Immunoglobulin (Human) — IVIG
Standard dose: 2 g/kg IV as a single infusion
Aseptic meningitis, hemolytic anemia, anaphylaxis in IgA-deficient patients, rare acute kidney injuryMay reduce the efficacy of live vaccines given within about 11 months of infusionReduces coronary artery aneurysm risk from roughly 25% (untreated) to under 5% when given within the first 10 days of fever onset.

Aspirin — Acute (Anti-Inflammatory) and Maintenance (Antiplatelet) Dosing

A deliberate, guideline-endorsed exception to the usual pediatric avoidance of aspirin due to Reye syndrome — see Common Errors to Avoid.

DrugDosageAdverse effectsDrug interactionsComments
Acetylsalicylic acid (ASA) — acute phase
Acute (anti-inflammatory) dose: 30-50 mg/kg/day PO divided every 6 hours (up to 80-100 mg/kg/day in some protocols)
GI upset, rare hepatotoxicity, tinnitus at high dosesAdditive bleeding risk with other antiplatelet agents or anticoagulantsContinue at this anti-inflammatory dose until the child has been afebrile for 24-48 hours.
Acetylsalicylic acid (ASA) — maintenance phase
Maintenance (antiplatelet) dose: 3-5 mg/kg PO once daily
GI upset, bleeding riskAdditive bleeding risk with other antiplatelet agents or anticoagulantsContinue for a minimum of 4-6 weeks, or longer if any coronary artery abnormality is present; switch to clopidogrel or dipyridamole if varicella or influenza develops.

Adjunctive and Second-Line Therapy — Higher IVIG-Resistance Risk or IVIG-Refractory Disease

Adding a corticosteroid or infliximab in this group reduces coronary aneurysm progression compared with IVIG alone; the specific choice among these options is specialist-directed.

DrugDosageAdverse effectsDrug interactionsComments
Prednisone / prednisolone
Standard dose: 2 mg/kg/day PO, maximum 60 mg/day
Hyperglycemia, mood changes, GI upset, immunosuppressionAdditive hyperglycemia with other agents affecting glucose controlTypical approach for up-front intensification in higher-risk patients, or for IVIG resistance; tapered per specialist direction.
Methylprednisolone sodium succinate (IV pulse)
Pulse dose: 30 mg/kg IV, maximum 1000 mg/dose
Hyperglycemia, hypertension, GI bleeding, adrenal suppression with repeated dosingAdditive hyperglycemia with other agents affecting glucose controlReserved specifically for Kawasaki disease shock syndrome or macrophage activation syndrome — not routine adjunctive use.
Infliximab
Standard dose: 5 mg/kg IV single infusion, specialist-directed
Infusion reactions, infection risk, rare hepatotoxicityAvoid with live vaccines; additive infection risk with other immunosuppressantsSecond-line biologic option for IVIG-resistant/refractory disease, alongside a repeat IVIG dose or a corticosteroid.
Anakinra
Dose: Specialist-directed, weight-based
Injection-site reactions, infection risk, neutropeniaAdditive infection risk with other immunosuppressantsA further-line option for refractory disease, particularly where hemoglobin has dropped more than 20 g/L after the first IVIG dose.

Alternative Antiplatelet Agents (Reye-Syndrome-Related Aspirin Substitution)

Use in place of low-dose aspirin if ASA is contraindicated, or if the child develops varicella or influenza during the maintenance antiplatelet phase.

DrugDosageAdverse effectsDrug interactionsComments
Clopidogrel
Dose: 1 mg/kg/day PO, maximum 75 mg/day, specialist-directed
Bleeding, GI upset, rare thrombocytopeniaAdditive bleeding risk with other antiplatelet agents or anticoagulantsA reasonable substitute for low-dose ASA specifically when Reye syndrome risk factors are present.
Dipyridamole
Dose: Specialist-directed, weight-based
Headache, dizziness, GI upsetAdditive bleeding risk with other antiplatelet agents or anticoagulantsAn alternative antiplatelet agent where clopidogrel is not preferred or available.

Anticoagulation — Large/Giant Coronary Artery Aneurysms Only

Reserved for the highest coronary-risk tier (Z-score ≥ 10, or ≥ 8 mm absolute diameter), added to ongoing antiplatelet therapy, with long-term specialized cardiology follow-up.

DrugDosageAdverse effectsDrug interactionsComments
Warfarin
Dose: Specialist-directed, titrated to INR target
Bleeding, requires frequent INR monitoring, numerous drug/food interactionsExtensive — CYP2C9/VKORC1-mediated interactions with many co-administered drugs and foods high in vitamin KThe traditional standard for long-term anticoagulation in large/giant aneurysms; titrated to a specialist-directed INR target.
Enoxaparin
Dose: Specialist-directed, weight-based
Bleeding, injection-site bruising, rare heparin-induced thrombocytopeniaAdditive bleeding risk with antiplatelet agents or anticoagulantsA low-molecular-weight heparin alternative to warfarin, particularly for bridging or shorter-term use.
Rivaroxaban
Dose: Specialist-directed, weight-based
Bleeding; fewer dietary interactions than warfarinAdditive bleeding risk with antiplatelet agents or anticoagulants; interacts with strong CYP3A4/P-glycoprotein inhibitors or inducersA direct oral anticoagulant (DOAC) option offering decreased monitoring requirements and fewer drug/food interactions than warfarin, where appropriate for the patient.

References

  1. Kawasaki disease: Practical guidance on diagnosis and management — Canadian Paediatric Society, Community Paediatrics Committee (Chen A, Rozenblyum E, Dahdah N, Lang B, Scuccimarri R, Lahiry P, Tam H, Chan M, Human A, Lee J, Wong P, Tsoukas P). Paediatr Child Health 2026;31(5):550-555
  2. Diagnosis, Treatment, and Long-Term Management of Kawasaki Disease: A Scientific Statement for Health Professionals From the American Heart Association — Circulation, American Heart Association (McCrindle BW, Rowley AH, Newburger JW, et al.). Circulation 2017;135(17):e927-e999
  3. Update on Diagnosis and Management of Kawasaki Disease: A Scientific Statement From the American Heart Association — Circulation, American Heart Association (Jone PN, Tremoulet A, Choueiter N, et al.). Circulation 2024;150(23):e481-e500

Professional reference only. Apply clinical judgment and verify patient-specific decisions against current authoritative guidance and product information.

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