Kawasaki disease (KD) is a vasculitis syndrome causing coronaritis in young children. As a result of the vascular damage, coronary lesions (CL), ectasia and aneurysms form in 20%-25% of the untreated children. The assessment of KD is difficult and challenging because of the lack of specific diagnostic or laboratory criteria. This is a retrospective study of 107 patients for a period of 21 years (1993-2014). In the cohort, 30.8% of patients had CL (19.6% had coronary aneurysms and 11.2% had significant coronary dilatations). The number of CL was high compared to that reported in international studies, although 45% of children were treated by modern protocols. In an attempt to analyse the reasons for the high coronary risk, the aim of this study was to investigate the clinical aspects of the disease and to establish the diagnostic problems causing diagnosis delay, which is subsequently related to increased coronary risk. The high incidence of the observed CL was associated with the failure of recognizing the disease, delayed diagnosis and, subsequently, lack of correct treatment. The analysis of the clinical presentation indicated significant correlation of gastrointestinal syndrome with typical and atypical KD. The incidence of the gastrointestinal syndrome correlated with the typical KD symptoms (p = 0.030), suggesting that it could be considered as a further diagnostic criterion.