The incidence of periungual desquamation and thrombocytosis in Kawasaki disease and the importance of systematic observation in the subacute phase.

Background: Periungual desquamation and thrombocytosis are characteristic of the subacute phase of Kawasaki disease (KD). However, accurate observations of periungual desquamation and thrombocytosis are lacking. Methods: This retrospective study included patients with acute-phase KD who received treatment at seven affiliated university hospitals in Korea between 2015 and 2017. Data were extracted from an anonymized registry established by the Korean Society of Kawasaki Disease. We investigated whether the findings of patients observed according to a set protocol until the subacute stage (group I) were different from those of patients observed without the use of a protocol (group II). Results: A total of 879 patients with KD were included in the analysis. Periungual desquamation was observed in 85% and 12.7% of patients in groups I and II, respectively. Thrombocytosis was observed in 76.7% and 44.7% of patients in groups I and II, respectively. Furthermore, compared to the initial test, the platelet counts of patients increased 100% and 67.9% in group I and II, respectively. When incomplete KD was defined only by the main symptoms during the acute stage and the diagnostic criterion of periungual desquamation during the subacute stage was excluded, the significant difference in the incidence of incomplete KD between groups I and II was no longer apparent. Conclusion: Performing regular and detailed observations has resulted in a higher incidence of periungual desquamation and thrombocytosis during the subacute phase of KD than those reported in recent studies. This indicates that until now, we have been neglecting the observation of symptoms and signs during the subacute phase. Regular monitoring during this period can also aid in differentiating suspected cases of KD and facilitate appropriate follow-up of complications.

Newly Developed Sex-Specific Z Score Model for Coronary Artery Diameter in a Pediatric Population.

BACKGROUND: This study aimed to generate a Z score calculation model for coronary artery diameter of normal children and adolescents to be adopted as the standard calculation method with consensus in clinical practice. METHODS: This study was a retrospective, multicenter study that collected data from multiple institutions across South Korea. Data were analyzed to determine the model that best fit the relationship between the diameter of coronary arteries and independent demographic parameters. Linear, power, logarithmic, exponential, and square root polynomial models were tested for best fit. RESULTS: Data of 2,030 subjects were collected from 16 institutions. Separate calculation models for each sex were developed because the impact of demographic variables on the diameter of coronary arteries differs according to sex. The final model was the polynomial formula with an exponential relationship between the diameter of coronary arteries and body surface area using the DuBois formula. CONCLUSION: A new coronary artery diameter Z score model was developed and is anticipated to be applicable in clinical practice. The new model will help establish a consensus-based Z score model.

Changes in the Clinical Characteristics of Kawasaki Disease After Coronavirus Disease (COVID-19) Pandemic: A Database Analysis.

BACKGROUND: The impact of the coronavirus disease 2019 (COVID-19) pandemic on Kawasaki disease (KD) has not yet been established. We investigated changes in the observed number and severity of KD cases and accompanying coronary artery complications during the COVID-19 pandemic in Korea. METHODS: This retrospective observational study included patients aged < 18 years with acute-phase KD diagnosed between March 2018 and February 2021. Data were extracted from the Clinical Data Warehouse that houses data from five affiliated university hospitals in Korea. We analyzed changes in the number of patient admissions and clinical characteristics, including cardiac complications, before and after the onset of the COVID-19 pandemic. RESULTS: A total of 475 admissions were included in the analysis. After March 2020, we observed a significant decrease of 33% in the number of hospitalizations for KD compared with the average number of hospitalizations during the previous 2 years. The number of admissions per month significantly decreased by 7.9 persons/month (95% confidence interval, -13.8 to -2.0; P < 0.05) compared with that before COVID-19. By contrast, the proportion of patients aged < 1 year with KD increased. The proportion of patients with refractory KD and the rate of cardiac complications did not change significantly. CONCLUSION: Since the onset of the COVID-19 pandemic, the total number of hospital admissions for KD has decreased in Korea. Although the proportion of admissions of infants aged < 1 year increased, no changes were observed in clinical courses and complications.

Epidemiology of Kawasaki Disease in South Korea: A Nationwide Survey 2015-2017.

BACKGROUND: This study aimed to investigate recent epidemiologic features of Kawasaki disease (KD) in South Korea. METHODS: The ninth triennial nationwide questionnaire survey collected data on the demographic findings, symptoms and signs, treatment patterns and coronary artery complications of acute-phase KD occurred in 2015-2017 from 98 hospitals with pediatric residency programs and 108 community hospitals without residency programs. RESULTS: We received data from 93 of the 98 hospitals (response rate: 94.9%) with residency programs and 75 of the 108 community-based children's hospitals (response rate: 69.4%) without residency programs. In the 3-year survey period, a total of 15,378 (5449 in 2015, 5171 in 2016 and 4758 in 2017) cases of KD were reported. The mean age at diagnosis was 33.0 ± 24.8 months (range: 0-205 months), and the male-to-female ratio was 1.41:1. The overall KD incidence was 196.9 (202.2 in 2015, 197.1 in 2016 and 191.0 in 2017) per 100,000 younger than 5 years population. Recurrent cases were 4.85%. KD occurred more frequently during winter (December-January) and late spring (May-June). Intravenous immunoglobulin (IVIG) was administered to 95% of the patients; nonresponder rate for the first IVIG was 14.8%. Coronary artery aneurysms and giant coronary artery aneurysms (internal diameter >8 mm) occurred in 1.7% and 19 patients, respectively. Two patients died due to multiorgan failure and hepatic encephalopathy. CONCLUSION: Peak incidence of KD in South Korea was 202.2 per 100,000 younger than 5 years population (2015), and the incidence of giant coronary artery aneurysm decreased to 0.09% (2017).

A Presumed Etiology of Kawasaki Disease Based on Epidemiological Comparison With Infectious or Immune-Mediated Diseases.

Background: Kawasaki disease (KD) may be associated with infection of unknown pathogen(s). For predicting of the etiology of KD, we evaluated epidemiological characteristics in KD, common infectious diseases and immune-mediated diseases in childhood. Methods: We respectively, reviewed the data of patients with KD, influenza, aseptic meningitis, exanthem subitum (ES), Mycoplasma pneumoniae (MP) pneumonia, acute pyelonephritis (APN), Henoch-Schönlein purpura (HSP), acute poststreptococcal glomerulonephritis (APSGN), and childhood asthma. We compared and interpreted epidemiological data across the groups. Results: In age distribution, KD, APN, and ES showed a similar pattern in that majority of patients were infants or young children, and other diseases showed a relatively even age-distribution which had a peak age, mainly 5-6 years, with bell-shape patterns. In annual-case pattern, there were epidemic years in aseptic meningitis and MP pneumonia, and the fluctuated annual cases were seen in other diseases. The trends of decreasing cases were seen in APSGN, HSP, and childhood asthma in recent years. In seasonal frequency, influenza or aseptic meningitis occurred in mainly winter or summer season, respectively. HSP and APSGN cases had less in summer, and KD, APN, and ES showed relatively even occurrence throughout a year without significant seasonal variations. Conclusions: Our results suggest that KD agents may be associated with normal flora that are influenced by environmental changes, since pathogens of APN and ES could be regarded as normal flora that originate from the host itself or ubiquitously existing human reservoirs.

Immunogenicity and safety of a combined DTPa-IPV/Hib vaccine administered as a three-dose primary vaccination course in healthy Korean infants: phase III, randomized study.

We assessed the immunogenicity and safety of a three-dose primary vaccination schedule with the combined diphtheria-tetanus-acellular pertussis-inactivated poliovirus/Haemophilus influenzae type b vaccine (DTPa-IPV/Hib) in Korean infants. In this phase III open-label, multicenter study (NCT01309646), healthy infants aged 42-69 days (randomized 1:1) received three doses of either pentavalent DTPa-IPV/Hib (DTPa-IPV/Hib group) or DTPa-IPV and Hib vaccines administered separately (DTPa-IPV+Hib group) at 2, 4, 6 months of age. The primary objective was to demonstrate non-inferiority of DTPa-IPV/Hib compared to DTPa-IPV+Hib vaccines in terms of immune responses to all vaccine antigens, 1 month post-dose 3. Solicited symptoms (local and general) were recorded during 4 days, and unsolicited adverse events (AEs) during 31 days, after each vaccination. Serious AEs (SAEs) were recorded throughout the study duration. The immunogenicity of the pentavalent DTPa-IPV/Hib vaccine was non-inferior compared to concomitant administration of DTPa-IPV+Hib vaccines. One month post-dose 3, nearly all infants had antibody levels above the seroprotective thresholds for anti-diphtheria toxoid, anti-tetanus toxoid, anti-polyribosyl-ribitol phosphate, and anti-poliovirus type 1, 2 and 3, and had antibody levels above the seropositive thresholds for anti-pertussis toxoid (PT), anti-filamentous hemagglutinin (FHA) and anti-pertactin (PRN) antibodies. A vaccine response for PT, FHA and PRN was observed in at least 96.7% of study participants. Anti-PRP geometric mean concentrations appeared lower for the DTPa-IPV/Hib group (8.456 µg/mL) than for the DTPa-IPV+Hib group (18.700 µg/mL). In both groups, the most common solicited symptoms were injection site redness and irritability. Fifty-seven SAEs were reported throughout the study; none were considered to be vaccination related.

Clinical implications in laboratory parameter values in acute Kawasaki disease for early diagnosis and proper treatment.

PURPOSE: This study aimed to analyse laboratory values according to fever duration, and evaluate the relationship across these values during the acute phase of Kawasaki disease (KD) to aid in the early diagnosis for early-presenting KD and incomplete KD patients. METHODS: Clinical and laboratory data of patients with KD (n=615) were evaluated according to duration of fever at presentation, and were compared between patients with and without coronary artery lesions (CALs). For evaluation of the relationships across laboratory indices, patients with a fever duration of 5 days or 6 days were used (n=204). RESULTS: The mean fever duration was 6.6±2.3 days, and the proportions of patients with CALs was 19.3% (n=114). C-reactive proteins (CRPs) and neutrophil differential values were highest and hemoglobin, albumin, and lymphocyte differential values were lowest in the 6-day group. Patients with CALs had longer total fever duration, higher CRP and neutrophil differential values and lower hemoglobin and albumin values compared to patients without CALs. CRP, albumin, neutrophil differential, and hemoglobin values at the peak inflammation stage of KD showed positive or negative correlations each other. CONCLUSION: The severity of systemic inflammation in KD was reflected in the laboratory values including CRP, neutrophil differential, albumin, and hemoglobin. Observing changes in these laboratory parameters by repeated examinations prior to the peak of inflammation in acute KD may aid in diagnosis of early-presenting KD patients.

Correlation between elevated platelet count and immunoglobulin levels in the early convalescent stage of Kawasaki disease.

Kawasaki disease (KD) may be an acute systemic immune-mediated disease which occurs after infection of unknown KD pathogen(s). The aim of this study is to evaluate the changes in platelet count and immunoglobulin (Ig) levels (IgG, IgM, IgA, and IgE) during hospitalization.Forty-three patients with complete KD who received intravenous Ig at 2 g/kg were enrolled in South Korea. The platelet count and Ig levels of the patients were examined twice at presentation and around discharge (mean 6.2 ±â€Š2.4 days apart) and the relationships between platelet level and Ig levels were evaluated.The mean patient age was 31 ±â€Š18 months; 28 patients were male and 15 were female. The values of all parameters measured, with the exception of IgE, were significantly increased at the second examination compared with their values at presentation. These values gradually increased over time after fever onset, over periods ranging from 2 to 16 days. The extent by which platelet levels increased over these 2 time points was correlated with the extents by which IgG (P < .01), IgM (P < .01), and IgA levels (P = .01) increased.Both the platelet count and the Ig (IgG, IgM, and IgA) levels increased with a correlation each other during the early convalescent stage of KD. This finding suggests that all Ig subtypes except IgE and platelets may be involved in the recovery from KD and that the extent of increased parameters may reflect the degree of systemic inflammation in acute KD.

Medium- or Higher-Dose Acetylsalicylic Acid for Acute Kawasaki Disease and Patient Outcomes.

OBJECTIVE: To investigate the effect of medium- or higher-dose acetylsalicylic acid (ASA) for treating acute-phase Kawasaki disease to prevent coronary artery aneurysm (CAA). STUDY DESIGN: Among the children with acute Kawasaki disease investigated in the eighth nationwide survey in the Republic of Korea, 8456 children with adequate data were included in this study. The subjects were divided into 2 groups according to the use of medium- or higher-dose ASA (≥30 mg/kg/day), or-low dose ASA (3-5 mg/kg/day) during the acute febrile phase. Both z- score-based criteria and Japanese criteria for CAA were used. RESULTS: The prevalence of CAA based on z-score (24.8% vs 18.3%; P = .001) and on the Japanese criteria (19.0% vs 10.4%; P < .001) was higher in the 7947 patients who received medium- or higher-dose ASA compared with the 509 patients who received low-dose ASA. The use of medium- or higher-dose ASA was a significant predictor of CAA based on both sets of criteria by univariate analysis (based on z-score: OR, 1.472, 95% CI, 1.169-1.854, P = .001; based on Japanese criteria: OR, 2.013, 95% CI, 1.507-2.690, P < .001) and multivariate logistic regression analysis (OR, 1.527, 95% CI, 1.166-2.0, P = .003 and OR, 2.198, 95% CI, 1.563-3.092, P < .001, respectively). CONCLUSIONS: The use of medium- or higher-dose ASA in acute Kawasaki disease did not prevent CAA. A future randomized controlled trial is needed to determine the optimum dose of ASA.

Epidemiology and Clinical Features of Kawasaki Disease in South Korea, 2012-2014.

BACKGROUND: To reveal the recent epidemiologic features of Kawasaki disease (KD) in South Korea based on data from a nationwide survey. METHODS: We collected data between 2012 and 2014 regarding the incidence, symptoms and signs, treatment trends and coronary complications associated with acute KD by sending questionnaires to 97 hospitals with pediatric residency programs as well as 19 community hospitals without residency training. RESULTS: We received full and partial data from 97 and 13 hospitals, respectively (response rate: 94.8%). A total of 14,916 cases of KD were reported by these 110 hospitals (4588 in 2012, 5183 in 2013 and 5145 in 2014). The male-to-female ratio was 1.4:1, and the median age at diagnosis was 29 months. The incidence of KD per 100,000 children younger than 5 years of age were 170.9, 194.9 and 194.7 in 2012, 2013 and 2014, respectively. The recurrence rate was 4.7%. KD occurred more frequently during summer (especially June and July) and winter (December and January) seasons. Intravenous immunoglobulin was administered to 95.4% of the patients, and the nonresponder rate for the first intravenous immunoglobulin was 11.8%. Coronary aneurysm occurred in 1.7% of the patients, and giant aneurysm developed in 19 patients (0.16%) during the 3 years. One patient had myocardial infarction and 1 patient died of suspected coronary aneurysm rupture. CONCLUSIONS: The incidence of KD in South Korea increased to 194.7 per 100,000 children younger than 5 years in 2014; meanwhile, the coronary aneurysm rate decreased to 1.7%.

Usefulness of anterior uveitis as an additional tool for diagnosing incomplete Kawasaki disease.

PURPOSE: There are no specific tests for diagnosing Kawasaki disease (KD). Additional diagnostic criteria are needed to prevent the delayed diagnosis of incomplete Kawasaki disease (IKD). This study compared the frequency of coronary artery lesions (CALs) in IKD patients with and without anterior uveitis (AU) and elucidated whether the finding of AU supported the diagnosis of IKD. METHODS: This study enrolled patients diagnosed with IKD at The Catholic University of Korea, Uijeongbu St. Mary's Hospital from January 2010 to December 2014. The patients were divided into 2 groups: group 1 included patients with IKD having AU; and group 2 included patients with IKD without AU. We analyzed the demographic and clinical data (age, gender, duration of fever, and the number of diagnostic criteria), laboratory results, and echocardiographic findings. RESULTS: Of 111 patients with IKD, 41 had uveitis (36.98%, group 1) and 70 did not (63.02%, group 2). Patients in group 1 had received a diagnosis and treatment earlier, and had fewer CALs (3 of 41, 1.7%) than those in group 2 (20 of 70, 28.5%) (P=0.008). All 3 patients with CALs in group 1 had coronary dilatation, while patients with CALs in group 2 had CALs ranging from coronary dilatation to giant aneurysm. CONCLUSION: The diagnosis of IKD is challenging but can be supported by the presence of features such as AU. Group 1 had a lower risk of coronary artery disease than group 2. Therefore, the presence of AU is helpful in the early diagnosis and treatment of IKD and can be used as an additional diagnostic tool.

Prediction of nonresponsiveness to medium-dose intravenous immunoglobulin (1 g/kg) treatment: an effective and safe schedule of acute treatment for Kawasaki disease.

PURPOSE: Medium-dose (1 g/kg) intravenous immunoglobulin (IVIG) is effective in the majority of patients with Kawasaki disease (KD) but some patients who do not respond to medium-dose IVIG are at high risk for the development of coronary artery lesions (CALs). The purpose of this study was to identify the clinical predictors associated with unresponsiveness to medium-dose IVIG and the development of CALs. METHODS: A retrospective study was performed in 91 children with KD who were treated with medium-dose IVIG at our institution from January 2004 to December 2013. We classified the patients into responders (group 1; n=68) and nonresponders (group 2; n=23). We compared demographic, laboratory, and echocardiographic data between the 2 groups. RESULTS: Multivariate logistic regression analysis identified 6 variables as predictors for resistance to medium-dose IVIG. We generated a predictive scoring system assigning 1 point each for percentage of neutrophils ≥65%, C-reactive protein≥100 mg/L, aspartate aminotransferase≥100 IU/L, and alanine aminotransferase≥100 IU/L, as well as 2 points for less than 5 days of illness, and serum sodium level≤136 mmol/L. Using a cutoff point of ≥4 with this scoring system, we could predict nonresponsiveness to medium-dose IVIG with 74% sensitivity and 71% specificity. CONCLUSION: If a patient has a low-risk score in this system, medium-dose IVIG can be recommended as the initial treatment. Through this process, we can minimize the adverse effects of high-dose IVIG and incidence of CALs.

Normal left ventricular torsion mechanics in healthy children: age related changes of torsion parameters are closely related to changes in heart rate.

BACKGROUND AND OBJECTIVES: This study was aimed at assessing left ventricular torsion (LVtor) mechanics using speckle tracking echocardiography (STE), establishing normal reference values of principal LVtor parameters, and analyzing the age-related changes in normal children. SUBJECTS AND METHODS: Eighty children (aged 3 months to 15 years) with normal cardiac function and rhythm were recruited. LVtor parameters including rotations, twist and untwist, torsion, and their rate indices were measured using STE. Age and heart rate related changes of the parameters were analyzed. RESULTS: Speckle tracking echocardiography analyses for LVtor parameters had excellent reliability in 64 of 80 subjects (80%) (intraclass correlation coefficients; 0.93-0.97). Early systolic twist (EST) motions (-8.4--0.1°) were observed in all subjects during an early 20±7% of systolic time intervals. The peak systolic twist and torsion were 17.0±6.5° and 2.9±1.3°/cm, respectively. The peak twist velocity was recorded at 51±13% of systolic time and the peak untwist velocity at 13.8±11.5% of diastolic time intervals. Multivariate analysis showed that heart rate change was an independent predictor of changes in torsion parameters; significantly decreasing LV length-normalized apical and basal rotation, torsion, and twist and untwist rate with increasing age. Isovolumetric recoil rate was independent of change in age and heart rate. CONCLUSION: Left ventricle showed unique torsion mechanics in children with EST, torsion, and untwists. Heart rate was an independent predictor of the change in torsion parameters with aging.

Evaluation of the Temporal Association between Kawasaki Disease and Viral Infections in South Korea.

BACKGROUND AND OBJECTIVES: This study is aimed at elucidating potential temporal associations between the occurrence of Kawasaki disease (KD) and various viral infections. SUBJECTS AND METHODS: We obtained monthly patterns of KD from the seventh nationwide survey and viral detection data from the Korea Centers for Disease Control and Prevention from 2009 to 2011 and evaluated temporal correlations between them for each month. The respiratory viruses detected using a multiplex real-time-polymerase chain reaction kit were influenza virus (A/H1N1, A/H3N2, A/H5N1, and B), adenovirus, parainfluenza virus (type 1, 2, 3), respiratory syncytial virus (type A, B), human rhinovirus, human coronavirus (OC43/229E, NL63), human bocavirus, and enterovirus. RESULTS: We obtained data from a total of 13031 patients who were treated for acute KD from 87 hospitals with pediatric residence programs. During this survey, KD showed highest overall incidence in summer and winter seasons and lowest incidence in February and October. We received viral detection data for a total of 14267 patients. Viral detection was highest during winter and spring seasons. The most commonly detected virus was human rhinovirus (32.6%), followed by influenza virus (26.8%). The monthly incidence of KD showed significant correlation with the monthly overall viral detection (p=0.022, r=0.382). In particular, human bocavirus and enterovirus have significant correlations with monthly patterns of KD occurrence (p=0.032 and p=0.007, respectively) and influenza virus correlated with KD occurrence with borderline significance (p=0.063). CONCLUSION: The temporal association between monthly occurrence of KD and viral detection suggests the etiologic importance of precedent infection in the development of KD.

Baseline heart rate variability in children and adolescents with vasovagal syncope.

PURPOSE: This study aimed to evaluate the autonomic imbalance in syncope by comparing the baseline heart rate variability (HRV) between healthy children and those with vasovagal syncope. METHODS: To characterize the autonomic profile in children experiencing vasovagal syncope, we evaluated the HRV of 23 patients aged 7-18 years and 20 healthy children. These children were divided into preadolescent (<12 years) and adolescent groups. The following time-domain indices were calculated: root mean square of the successive differences (RMSSD); standard deviation of all average R-R intervals (SDNN); and frequency domain indices including high frequency (HF), low frequency (LF), normalized high frequency, normalized low frequency, and low frequency to high frequency ratio (LF/HF). RESULTS: HRV values were significantly different between healthy children and those with syncope. Student t test indicated significantly higher SNDD values (60.46 ms vs. 37.42 ms, P=0.003) and RMSSD (57.90 ms vs. 26.92 ms, P=0.000) in the patient group than in the control group. In the patient group, RMSSD (80.41 ms vs. 45.89 ms, P=0.015) and normalized HF (61.18 ms vs. 43.19 ms, P=0.022) were significantly higher in adolescents, whereas normalized LF (38.81 ms vs. 56.76 ms, P=0.022) and LF/HF ratio (0.76 vs. 1.89, P=0.041) were significantly lower in adolescents. In contrast, the control group did not have significant differences in HRV values between adolescents and preadolescents. CONCLUSION: The results of this study indicated that children with syncope had a decreased sympathetic tone and increased vagal tone compared to healthy children. Additionally, more severe autonomic imbalances possibly occur in adolescents than in preadolescents.

Changes in Kawasaki disease during 2 decades at a single institution in Daejeon, Korea.

BACKGROUND: The goal of this study is to evaluate the changes in the epidemiologic and clinical features of Kawasaki disease (KD) in a period of 20 years. METHODS: We compared the epidemiologic features of 3 KD patient groups: those admitted from 1987 to 1990 (122 cases), from 1997 to 2000 (137 cases) and from 2007 to 2010 (102 cases). For clinical features, we reviewed the medical records of patients admitted from 1996 to 2000 (141 cases) and from 2006 to 2010 (121 cases). RESULTS: There were a total of 772 KD patients during the study period (mean age: 27.2 months; male-to-female ratio: 1.6:1). There were some variations in the mean ages (23.8, 27.8 and 30 months), in the male-to-female ratios (1.9:1, 1.3:1 and 1.8:1) and in the age distributions, including the patients of ages <6 months and >5 years, but the differences were not statistically significant across the groups. The seasonal distributions were relatively consistent with some variations. In clinical features, the preadmission and total fever durations were shorter (P < 0.001, respectively), and the proportions of incomplete KD tended to increase, and the rates of coronary artery aneurysm tended to decrease in recently admitted patients. CONCLUSIONS: There were no significant changes in the demographic and seasonal features of KD, although the evaluation of the clinical features showed shorter fever duration suggestive of improved identification and treatment of KD over time.

Epidemiologic features of Kawasaki disease in South Korea: data from nationwide survey, 2009-2011.

BACKGROUND: To assess the recent epidemiologic features of Kawasaki disease (KD) in South Korea from the nationwide survey conducted between 2009 and 2011. METHODS: We collected data regarding the incidence, symptoms, treatment and coronary complications associated with acute KD by sending questionnaires to the 100 hospitals that have pediatric residency programs from 2009 to 2011. RESULTS: We received complete responses from 73 hospitals and partial responses from 14 hospitals. A total of 13,031 patients of KD were reported from the 87 hospitals (3941 in 2009, 4635 in 2010 and 4455 in 2011). The male to female ratio was 1.44:1, and the median age at diagnosis was 28 months. From the questionnaires with complete responses, we noted that the incidence of KD per 100,000 children <5 years of age was 115.4 in 2009, 132.9 in 2010 and 134.4 in 2011 (average rate, 127.7). KD occurred more frequently during summer (June, July and August) and during winter (December and January). The recurrence rate was 3.83%. The standard dose of intravenous immunoglobulin was administered to 93.6% of the patients, and nonresponder rate was 11.6%. Coronary aneurysm occurred in 1.9% of the patients and giant aneurysm developed in 26 patients (0.26%) over 3 years, and 2 patients had myocardial infarction. No mortality was reported. CONCLUSIONS: The average annual incidence of KD in South Korea has continuously increased to 134.4 per 100,000 children <5 years of age in 2011, which is the second highest incidence of KD worldwide, following its incidence in Japan.