[1] Department of Dermatology, The Royal London Hospital, London
[2] Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London
[3] Department of Dermatology, University College London Hospitals Nhs Foundation Trust, London
[4] Hospital for Tropical Diseases, University College London Hospitals Nhs Foundation Trust, London
[5] Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London