1. Department of Dermato-Allergology, National Allergy Research Centre; Copenhagen University Hospital Gentofte; Hellerup; 2900; Denmark
2. Department of Dermato-Allergology; Copenhagen University Hospital Gentofte; Hellerup; 2900; Denmark
3. The National Research Centre for the Working Environment; Copenhagen 2100; Denmark
4. Department of Occupational and Environmental Medicine; Copenhagen University Hospital Bispebjerg; Copenhagen 2400; Denmark