TABLE 101.17 DIFFERENTIAL DIAGNOSIS OF KAWASAKI DISEASE KD is most commonly confused with exanthematous infections of childhood ( Table 101.17 ) Measles, echovirus, and adenovirus may share many of the signs of mucocutaneous inflammation, but they typically have less evidence of systemic inflammation, and generally lack the extremity changes seen in KD Toxin-mediated illnesses, especially β-hemolytic streptococcal infection and toxic shock syndrome, generally lack the ocular and articular involvement typical of KD Finally, drug reactions such as Stevens–Johnson syndrome or serum sickness may mimic KD but with subtle differences in the ocular and mucosal manifestations Triage Considerations Young children with prolonged fever, especially in the setting of irritability or fussiness, in association with one or more of the following cardinal signs, conjunctivitis, rash, mucosal inflammation, cervical lymphadenopathy, or extremity changes, should lead to prompt evaluation for KD The most serious complications of KD are cardiac and the major complication is coronary artery aneurysms Infants younger than year of age have the highest risk of developing coronary artery aneurysms A rare but potentially life-threatening complication is Kawasaki shock syndrome It is defined as systolic hypotension for age, a sustained decrease in systolic blood pressure from baseline of ≥20%, or clinical signs of poor perfusion Clinical Assessment The conventional diagnostic criteria are particularly useful in preventing overdiagnosis, but they may result in failure to recognize incomplete forms of the illness It should be emphasized that children who not fulfill formal diagnostic criteria are still at risk of