1 Department for Endocrinology, Whipps Cross University Hospital, Barts Health NHS Trust, London, UK. Electronic address: jeffrey.harte@bartshealth.nhs.uk.
2 Department for Renal Medicine, Whipps Cross University Hospital, Barts Health NHS Trust, London, UK.
3 Department of Photodermatology, St Johns Institute of Dermatology, Guy's and St Thomas' Hospital, London, UK.