Age-related differences in the course of the acute phase symptoms of Kawasaki disease.

Background: Knowledge about age-related differences in the course of the acute phase symptoms is helpful to make an accurate and timely diagnosis of Kawasaki disease (KD).

Methods: We performed a retrospective study involving 100 consecutive patients with KD. Time to the first detection of the principal symptoms was examined. The first day of fever was defined as day 1.

Results: Median age was 24 months. In patients >24 months, cervical lymphadenopathy was the earliest symptom other than fever and appeared earlier than in younger patients (2.6 ± 2.2 versus 3.8 ± 1.9 days of illness; P < 0.0001). Of the total, 67% of the older patients initially presented with cervical lymphadenopathy alone, which remained the only symptom for 2.8 days on an average. In younger patients, polymorphous rash was the most common initial symptom and appeared earlier than in older patients (2.8 ± 1.6 versus 4.2 ± 1.8 days of illness; P < 0.0001). Time to diagnosis since the initial symptoms was shorter in younger patients (2.1 ± 1.5 versus 3.2 ± 1.6 days; P = 0.006).

Conclusions: A high index of suspicion for KD is required in febrile patients ≤24 months presenting with rash and in those >24 months with cervical lymphadenopathy. Younger patients need close observation because their acute phase symptoms progress rapidly. On the contrary, in older patients, cervical lymphadenopathy often remains the only manifestation for more than a few days and complicates the diagnosis. Recognizing age-specific patterns is useful for accurate and timely diagnosis of KD.