1. The University of Nottingham; c/o Cochrane Skin Group; A103, King's Meadow Campus Lenton Lane Nottingham UK NG7 2NR
2. University Hospital of Wales; Department of Dermatology; Heath Park Cardiff Wales UK CF14 4XW
3. Imperial College London; Section of Paediatrics, Division of Infectious Diseases, Department of Medicine; Wright Fleming Building Norfolk Place London UK W2 1PG
4. Imperial College London; Department of Epidemiology and Biostatistics; Faculty of Medicine St Mary's Campus, Norfolk Place London UK W2 1PG
5. The University of Nottingham; Centre of Evidence Based Dermatology; Queen's Medical Centre Derby Road Nottingham UK NG7 2UH
6. University of Virginia; Department of Medicine, Division of Asthma, Allergy and Immunology; Box 801355 Charlottesville Virginia USA 22901