[1] Epsom & St Helier Univ Hosp NHS Trust, Dept Dermatol, Carshalton, England
[2] Croydon Univ Hosp, Croydon, England
[3] Kingston Hosp NHS Fdn Trust, Dept Dermatol, Kingston, England
[4] St Georges Univ Hosp NHS Trust, Dept Dermatol, London, England
[5] St Georges Univ London, Populat Hlth Res Inst, London, England