Differences in the Clinical Characteristics of Kawasaki Disease Between Older and Younger Children (2015-2019): A Single-Center, Retrospective Study

The objective of this study was to investigate the differences in the clinical characteristics of Kawasaki disease between older and younger children.This retrospective study examined 405 children with Kawasaki disease admitted to Showa University Northern Yokohama Hospital between 2015 and 2019.Eligible patients were classified into the older (≥3.0 years of age, n = 169) and younger (<3.0 years of age, n = 236) groups. Skin rash was found in significantly fewer cases (112 [66.3%] vs 229 [97.0%], P < .001 in the younger group). Cervical lymphadenopathy was more common in older children (153 [90.5%] vs 165 [69.9%], P < .001) and in incomplete Kawasaki disease (3 or 4 findings) (34 [20.1%] vs 25 [10.6%], P = .0078). The diagnosis was more delayed in older children (median: 5.0 days vs 4.0 days, P = .003) than the younger group. Additionally, fever nonresponsive to a single intravenous immunoglobulin was more common, and the duration of fever was significantly longer in the older group (48 [28.4%] vs 47 [19.9%], P = .0479).Kawasaki disease should be suspected in children aged >3.0 years with cervical lymphadenopathy and fever, despite the absence of skin rash. Additionally, incomplete Kawasaki disease, fever unresolved by a single intravenous immunoglobulin infusion, and the tendency to delay treatment initiation are more common in children aged >3.0 years.