[1] Royal Liverpool & Broadgreen Univ Hosp NHS Trust, Broadgreen Hosp, Dept Dermatol, Liverpool L14 3LB, Merseyside, England
[2] Barts Hlth NHS Trust, Royal London Hosp, Dept Dermatol, London, England
[3] Great Ormond St Hosp Sick Children, Dept Dermatol, London, England