1. Department of Dermatology, The Skin Hospital, Quay Street, Manchester M3 3HL, UK
2. Department of Dermatology, Royal Victoria Infirmary, Belfast, UK
3. Department of Dermatology, University Hospital, Lund, Sweden
4. Department of Dermatology, The Royal Liverpool Hospital, Prescott Street, PO Box 147, Liverpool L69 3BX, UK