1. Centre of Evidence Based Dermatology; University of Nottingham; King's Meadow Campus Lenton Lane Nottingham NG7 2NR U.K
2. Nuffield Department of Clinical Medicine; Oxford University; Oxford OX3 7BN U.K
3. Medical Research Council Clinical Trials Unit; Aviation House 125 Kingsway London WC2B 6NH U.K
4. School for Medicine; Pharmacy and Health; Wolfson Research Institute; Durham University; Stockton on Tees TS17 6BH U.K
5. Nottingham Clinical Trials Unit; Nottingham Health Science Partners; C Floor South Block Nottingham U.K
6. Dermatology Department; Queen's Medical Centre; University of Nottingham; Nottingham NG7 2UH U.K