1. Leeds Centre for Dermatology, Chapel Allerton Hospital; Leeds LS7 4SA UK
2. Centre for Occupational and Environmental Health, Centre for Epidemiology, Institute of Population Health, Faculty of Medical and Human Sciences, The University of Manchester; Manchester M13 9PL UK
3. St Mary's Hospital, Manchester Academic Health Science Centre, Central Manchester University Hospitals NHS Foundation Trust; Manchester M13 9WL UK