Signs and Symptoms of Kawasaki Disease
Classic Kawasaki disease is diagnosed by fever lasting ≥5 days plus at least 4 of 5 principal clinical features: oral mucosal changes, bilateral nonexudative conjunctivitis, polymorphous rash, extremity changes, and cervical lymphadenopathy. 1
Diagnostic Criteria
The diagnosis requires fever for at least 5 days (counting the first day of fever as day 1) combined with ≥4 of the following 5 principal features 1:
The Five Principal Clinical Features:
Oral mucosal changes: Erythema and cracking of lips, strawberry tongue, and/or erythema of oral and pharyngeal mucosa
Bilateral bulbar conjunctival injection: Nonexudative, usually begins shortly after fever onset, often spares the limbus (avascular zone around the iris). Anterior uveitis may be observed on slit-lamp examination 1
Polymorphous rash: Most commonly diffuse maculopapular eruption. Also includes scarlatiniform erythroderma or erythema multiforme-like patterns. Typically extensive on trunk and extremities with characteristic accentuation in the groin with early desquamation 1
Extremity changes:
- Acute phase: Erythema of palms and soles with firm, sometimes painful induration of hands or feet
- Subacute phase: Periungual desquamation beginning 2-3 weeks after fever onset, may extend to palms and soles
- Later: Beau's lines (deep transverse nail grooves) at 1-2 months 1
Cervical lymphadenopathy: Usually unilateral, ≥1.5 cm diameter, confined to anterior cervical triangle. This is the least common of the principal features 1
Fever Characteristics
Fever is typically high-spiking (>39°C to 40°C) and remittent. Without treatment, fever persists 1-3 weeks. Fever usually resolves within 36 hours after IVIG completion; persistence indicates IVIG resistance requiring further therapy 1.
Timing Considerations
A critical pitfall: Not all clinical features present simultaneously. Diagnosis is often impossible very early in the course. Some features may have resolved by presentation after 1-2 weeks of fever—careful history of prior signs and symptoms is essential 1.
Experienced clinicians may diagnose with only 4 days of fever when ≥4 principal features are present, particularly with hand/foot involvement, or rarely with 3 days of fever in classic presentations 1.
Additional Clinical Manifestations
Beyond the principal features, patients commonly exhibit 1:
Musculoskeletal:
- Arthritis, arthralgia with synovial fluid pleocytosis
Gastrointestinal:
- Diarrhea, vomiting, abdominal pain
- Hepatitis, jaundice
- Gallbladder hydrops
- Pancreatitis
Laboratory Findings:
- Normal or elevated WBC with neutrophil predominance
- Elevated acute phase reactants (CRP, ESR)
- Low serum sodium and albumin
- Elevated liver enzymes
- Sterile pyuria
- Thrombocytosis in second week after fever onset 1
Important Diagnostic Caveats
Features that argue AGAINST Kawasaki disease 1:
- Exudative conjunctivitis
- Exudative pharyngitis
- Oral ulcerations
- Splenomegaly
- Vesiculobullous or petechial rashes
- Bullous rashes
Cervical lymphadenopathy can mimic bacterial lymphadenitis, potentially delaying diagnosis. In KD, multiple lymph nodes are enlarged with retropharyngeal edema or phlegmon common. Ultrasound/CT can differentiate: bacterial lymphadenitis typically shows a single node with hypoechoic core 1.
Incomplete Kawasaki Disease
Patients with fever ≥5 days and only 2-3 principal features should be evaluated for incomplete KD, particularly infants <6 months who are at highest risk for coronary artery aneurysms and atypical presentations 2, 3. If coronary artery abnormalities are detected on echocardiography, the diagnosis is confirmed in most cases 1.