Kawasaki Disease at 50 Years.

Importance: Kawasaki disease (KD) is the most recognized vasculitis of childhood. The condition's characteristic high fever, rash, mucositis, conjunctivitis, lymphadenopathy, and extremity changes are superficially unexceptional, and resolve spontaneously within a mean of 12 days. It is the acuity and the potential for life-changing damage to the coronary arteries that distinguish KD from conditions that mimic it and exemplify the unique aspects and challenges of vascular inflammation in children. Observations: Although KD is an orphan disease, its role as a leading cause of acquired heart disease in children has led to significant efforts to determine its etiology, optimize diagnosis, and customize treatment according to individuals' needs. The result is that KD can now be controlled without sequelae in more than 95% of cases. Furthermore, advances in stratifying patients according to measurable risk factors allow therapy to be personalized in increasingly effective ways. High-risk patients, such as infants younger than 6 months, those with early evidence of coronary artery dilatation, and those with extreme abnormalities in laboratory test results, are often identified at presentation. This early identification allows them to be treated with corticosteroids in addition to intravenous immunoglobulin to improve their outcomes. Children with similar findings on laboratory tests and echocardiography may be treated based on algorithms for managing "incomplete KD" despite falling short of fulfilling classic diagnostic criteria. Children who do not respond to intravenous immunoglobulin are the focus of trials to minimize the duration of inflammation and thereby protect their coronary arteries in ways never before considered. Conclusions and Relevance: Kawasaki disease is a hybrid condition at the junction of infectious diseases, immunology, rheumatology, and cardiology. Rather than being left an orphan disease, KD is bringing disciplines together to identify its genetic, pathophysiological, and hemodynamic features. In turn, this work promises to shed light on many other inflammatory conditions as well.