Kawasaki disease in adolescents: age-specific clinical features and factors associated with outcomes

In adolescents, Kawasaki disease (KD) often manifests with non-specific clinical symptoms, which delays diagnosis and treatment and consequently increases the risk of coronary artery lesions (CALs). This study investigated the clinical characteristics of KD across age groups, focusing on adolescents, and identified age-specific factors associated with treatment resistance and CALs.

A retrospective analysis was conducted using nationwide survey data compiled in South Korea from 2009 to 2017.

A total of 34,408 patients with KD were stratified into four age groups at the time of diagnosis: < 1 year (7425; 21.6%), 1-4 years (22,629; 65.8%), 5-9 years (4089; 11.9%), and ≥ 10 years (265; 0.8%). Compared to younger age groups, the ≥ 10-year age group had a greater proportion of males, longer total and pre-admission fever duration, a greater likelihood of incomplete KD with fewer typical symptoms, more cervical lymphadenopathy, and less erythema at the Bacillus Calmette-Guérin inoculation site. Although some differences were not statistically significant, this group had higher rates of unresponsiveness to first and second intravenous immunoglobulin (IVIG) treatments and second-line steroid use, and more coronary dilatation and aneurysms, but no differences in coronary stenosis, occlusion, or mortality. In adolescents, IVIG unresponsiveness was only associated with prolonged fever, and CALs was associated with recurrent KD, prolonged fever, lower total protein levels, and fewer acute-phase extremity changes.

Adolescents with KD exhibit distinct clinical features, characteristic age-specific risk factors, and a higher risk of CALs, highlighting the need for age-specific management strategies. Key Points • KD in adolescence is rare, accounting for approximately 0.8% of all cases. • Adolescents with KD exhibited longer fever duration, more incomplete KD presentation, higher rates of unresponsiveness to IVIG, and a greater incidence of CALs. • Prolonged fever and recurrent KD were associated with treatment resistance and CALs in adolescent KD.