Paediatric Vasculitis: Kawasaki Disease & IgA Vasculitis (HSP)

The two most common childhood vasculitides, covered together here.

Kawasaki Disease

Second most common childhood vasculitis (after IgA vasculitis/HSP, below). A clinical diagnosis. Early treatment with IVIg reduces morbidity and mortality.

• Demographics: 85% <5 years old; more common in children of Asian background.

Diagnostic criteria

Fever for ≥5 days AND 4 of the following 5:

1. Conjunctivitis (bilateral, non-purulent)
2. Cervical lymphadenopathy
3. Rash — variable, but not vesicular or crusting; may be urticarial, morbilliform, or resemble scarlet fever
4. Lip/oral mucosal involvement — redness/cracking of the lips, diffuse oropharyngeal erythema, strawberry tongue
5. Extremity oedema/erythema progressing to desquamation, often with perineal desquamation

Children may not show all features — urgent paediatric review may be warranted with as few as 2 features present, given the consequences of a missed diagnosis.

Investigations

Echocardiogram at baseline, then at 6 weeks (coronary artery aneurysm surveillance).

Management

• IVIg 2 g/kg.
• High-dose aspirin until fever resolves (30–100 mg/kg/day in 4 divided doses), then low-dose aspirin (3–5 mg/kg daily) for 6 weeks if no coronary artery lesions are found.
• If coronary artery lesions are detected on echo, continue aspirin.
• Corticosteroids — controversial; used if fever persists after IVIg.

IgA Vasculitis (Henoch-Schönlein Purpura)

The most common vasculitis in children — can occur at any age.

Clinical features

Palpable purpura over the lower limbs up to the buttocks; large-joint arthritis; abdominal pain. Typically follows a URTI, associated with strep throat — a post-streptococcal complication. Most recover within a few months.

Complications

May develop IgA nephritis. Other serious complications: GI haemorrhage (melaena), intussusception, scrotal involvement.

Treatment

Symptomatic. Monitor for renal involvement — UEC and early morning urine for protein.