1. Departments of Dermatology and
2. Department of Dermatology, Hospital de la Santa Creu I Sant Pau, Barcelona, Spain;
3. Division of Dermatology (Pediatrics), CHU Sainte-Justine, University of Montreal, Montreal, Canada;
4. Department of Dermatology, Hospital for Sick Children, University of Toronto, Toronto, Canada;
5. Center for Vascular Anomalies, Division of Plastic Surgery, Cliniques Universitaires St Luc, Brussels, Belgium;
6. Departments of Dermatology and Pediatrics, Columbia University, New York, New York;
7. Departments of Dermatology and Pediatrics, Indiana University, School of Medicine, Indianapolis, Indiana;
8. Department of Oncology, Cincinnati Children’s Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio;
9. Department of Dermatology, Medical College of Wisconsin, Milwaukee, Wisconsin;
10. Division of Dermatology, Children’s Mercy Hospitals and Clinics, Kansas City, Missouri; and
11. Department of Dermatology, National Institute of Pediatrics, Mexico City, Mexico
12. Epidemiology and Biostatistics, University of California at San Francisco, San Francisco, California;