What are the signs and symptoms of Kawasaki disease?

Kawasaki Disease: Signs and Symptoms

Diagnostic Criteria

Kawasaki disease is diagnosed by fever lasting at least 5 days plus at least 4 of 5 principal clinical features: bilateral conjunctival injection, oral mucosal changes, polymorphous rash, extremity changes, and cervical lymphadenopathy. 1, 2

Fever Characteristics

• High-spiking fever typically exceeding 39-40°C (102.2-104°F) is the hallmark feature 1, 2
• Without treatment, fever persists for an average of 11 days, though it can last several weeks 1
• Diagnosis can be made with only 4 days of fever when ≥4 principal features are present, particularly with hand/foot swelling 1, 2
• Experienced clinicians may diagnose with 3 days of fever in rare classic presentations 1, 2

The Five Principal Clinical Features

1. Extremity Changes

Acute phase:

• Erythema of palms and soles with sharp demarcation at ankles and wrists 1
• Firm, sometimes painful induration of hands or feet 1

Convalescent phase (2-3 weeks after onset):

• Membranous desquamation beginning in periungual region 1
• Deep transverse grooves across nails (Beau's lines) at 1-2 months 1

2. Oral Mucosal Changes

• Erythema and cracking of lips 1
• Strawberry tongue 1
• Diffuse injection of oral and pharyngeal mucosae without focal lesions, ulcerations, or exudates 1

3. Bilateral Conjunctival Injection

• Nonexudative, primarily bulbar conjunctival injection 1
• Typically spares the limbus (avascular zone around iris) 1
• Photophobia and eye pain are usually absent 1
• Anterior uveitis often observed by slit-lamp examination during first week 1

4. Polymorphous Rash

• Appears within first 5 days of illness, typically truncal with groin accentuation 1
• Most commonly diffuse maculopapular eruption 1
• May also appear urticarial, scarlatiniform, erythema multiforme-like, or as erythroderma 1
• Critical distinction: Bullous and vesicular lesions are NOT consistent with Kawasaki disease 1

5. Cervical Lymphadenopathy

• Least common principal feature 1
• Usually unilateral, ≥1.5 cm diameter, confined to anterior cervical triangle 1
• May be the most prominent initial finding, especially in older children, leading to misdiagnosis as bacterial lymphadenitis 1

Additional Clinical Findings (Not Required for Diagnosis)

Cardiovascular

• Gallop rhythm or distant heart sounds 1
• ECG changes including arrhythmias, prolonged PR/QT intervals, ST-T wave changes 1
• Pericardial effusion, decreased ventricular function, mild valvular regurgitation 1

Gastrointestinal

• Diarrhea, vomiting, abdominal pain 1
• Hydrops of gallbladder 1
• Mild jaundice and elevated transaminases 1

Laboratory Abnormalities

• Markedly elevated ESR (often >40 mm/hr, commonly ≥100 mm/hr) and CRP (typically ≥3 mg/dL) 1
• Leukocytosis with left shift 1
• Thrombocytosis in subacute phase (second week) 1, 2
• Hypoalbuminemia and mild anemia 1
• Sterile pyuria of urethral origin 1

Musculoskeletal

• Arthralgia and arthritis present in approximately one-third of patients in acute phase 1, 2

Neurological

• Striking irritability 1
• Mononuclear pleocytosis in cerebrospinal fluid 1

Respiratory

• Cough, rhinorrhea, pulmonary infiltrates 1

Incomplete (Atypical) Kawasaki Disease

Consider incomplete Kawasaki disease in children with fever ≥5 days AND only 2-3 principal features, or infants with fever ≥7 days without explanation. 2, 3

High-Risk Populations Requiring Extra Vigilance

• Infants <6 months: May present with only prolonged fever and irritability, yet have the highest risk of coronary abnormalities 2, 3
• Older children and adolescents: Often have delayed diagnosis and higher prevalence of coronary artery abnormalities 2, 3

Evaluation Algorithm for Incomplete Disease

• Check inflammatory markers (ESR, CRP) 2, 3
• If elevated, measure serum albumin, transaminases, complete blood count, and urinalysis 1
• Obtain echocardiography to assess for coronary artery abnormalities 1, 3
• Diagnosis can be made with only 3 clinical features if coronary artery abnormalities are detected 1

Critical Diagnostic Pitfalls to Avoid

Features that should prompt consideration of alternative diagnoses:

• Exudative conjunctivitis or pharyngitis 1
• Discrete intraoral lesions or ulcerations 1
• Bullous or vesicular rash 1
• Generalized lymphadenopathy 1

Common mimics to exclude:

• Viral infections (adenovirus, measles) 3
• Scarlet fever (look for circumoral pallor, Pastia's lines, peripheral eosinophilia) 4
• Toxic shock syndrome (thrombocytopenia rather than thrombocytosis) 4
• Drug reactions 1

Clinical Significance

Early recognition is critical because treatment with IVIG and aspirin within 10 days of fever onset significantly reduces coronary artery abnormality risk from 15-25% to <5%. 2, 5 Fever typically resolves within 36 hours after IVIG completion; persistence indicates IVIG resistance requiring further therapy 1, 2.