Kawasaki disease (KD) is currently the leading cause of acquired heart diseases in children in developed countries. Cardiac involvement is the main determinant of the long-term prognosis of these patients, as coronary aneurisms (CAAs) may lead to ischemic heart disease and even sudden death. The current standard of care for KD has consistently reduced CAAs frequency from 25-30% to about 5%. Unfortunately, 10-20% of KD patients results resistant to standard treatment leading to a major risk of cardiac complications. Thus, scoring systems have been constructed in order to identify patients likely to be resistant to IVIG and who may benefit from more aggressive initial therapy. Different scoring scales developed by Kobayashi, Egami et Sano had shown a good sensitivity (77-86%) and specificity (67-86%) in predicting IVIG unresponsiveness in Japanese populations. However, their predictive value was not confirmed by subsequent studies in different ethnic populations. Recently, the French Kawanet group have proposed a IVIG unresponsiveness score that provided good sensitivity and acceptable specificity in a non-Asian KD population even if it was not subsequent validated by an external study. In our study population, the achievement of specificity and sensitivity values for both scores consistent with those reported by the original studies (sensitivity 70% and specificity 80% for Kobayashi and sensitivity 77% and specificity 60% for Kawanet), will be considered a success.

Inclusion Criteria:

• Patients aged less than 18 years at diagnosis
• Diagnosis of KD according to the AHA criteria

Exclusion Criteria:

• Patients who do not meet the criteria for KD
• Patients for which an alternative infectious diagnosis was not investigated and/or excluded.

The setting is represented by 1 Asian and 4 European pediatric rheumatology centres which with internationally recognized expertise in the treatment and follow-up of a large number of Kawasaki disease patients