The cause of Kawasaki syndrome remains unknown; an infectious agent is suspected because of the following
• Seasonal peak in the winter and spring months in most geographic areas.
• Geographic focal epidemics occurred in the 1970s and 1980s.
Burns et al., point out that ‘‘peak incidence in the toddler age-group with only rare cases in infants under 3 months of age and in adults suggests a role for trans¬placental antibodies conferring protection and develop¬ment of protective immunity as a result of asymptomatic infection in most individuals.’’ Burns et al, suggest that ‘‘Research should focus on unique features of the vasculitis that might serve as a diagnostic test, even if the underlying cause remains unknown.’’
Kawasaki syndrome and polyarteritis nodosa possess similarities and essential differences:
• Coronary artery aneurysms occur in about 20% of children with kawasaki and in less than 1% with polyarteritis nodosa.
• The pattern of inflammation in Kawasaki reveals infiltration of CD8-positive T cells and macrophage and few polymorphonuclear cells with prominent edema without fibrinoid necrosis versus prominent fibronoid necrosis, a hallmark of polyarteritis nodosa.