1 Division of Dermatology, Department of Paediatrics, University of Toronto, Toronto, Ontario, Canada. Electronic address: Cathryn.sibbald@sickkids.ca.
2 Department of Medicine, Division of Dermatology, University of Toronto, Toronto, Ontario, Canada.
3 Division of Clinical Pharmacology and Toxicology, Department of Paediatrics, Hospital for Sick Children, Toronto, Ontario, Canada; Division of Rheumatology, Department of Paediatrics, Hospital for Sick Children, Toronto, Ontario, Canada.