Objective: Kawasaki disease (KD) is a childhood vasculitis, and the inflammation of coronary arteries is the most severe complication of KD. Despite the fever, diagnosis may be delayed when clinical symptoms do not fulfill the criteria. In this study, we aimed to determine whether the complete blood count (CBC) parameters can differentiate KD from other diseases that caused fever in children.

Methods: The present study included 51 patients, 21 of whom were diagnosed as KD and 30 febrile non-KD patients who had viral or infections. We analyzed groups' initial CBC parameters in the first visit.

Results: Fourteen of the 21 patients (66%) were atypical KD. There were no statistically significant differences in patients' characteristics, clinical symptoms, and signs between the groups. Six of the patients had abnormal coronary arteries like dilatation. A higher neutrophil-to-lymphocyte ratio (NLR) (2.5 (1.8–5.9) vs. 1.41 (0.89–3.6); p=0.028, retrospectively) and higher CRP levels (58.1 (25.6–129.3) vs. 22.8 (4.3–41.6); p= 0.021, retrospectively) were found in KD group when compared with non- KD group. When combining NLR> 1.41 and CRP> 31 mg/L, there was a higher odds ratio of 24.84 (95% confident interval (2.41–198.53) of KD predicting the possibility.

Conclusion: Neutrophil-to-lymphocyte ratio and CRP can show inflammation and immune reactivity, and they can be used to distinguish KD patients from virally infected children.

Keywords: febrile children, kawasaki disease, neutrophil-to-lymphocyte ratio, C reactive protein.