1. Department of Medical Informatics, Biometry and Epidemiology; University of Erlangen/Nürnberg; 91054 Erlangen Germany
2. Contact Allergy Unit, Department of Dermatology; University Hospital K.U. Leuven; 3000 Leuven Belgium
3. Department of Dermatology; University Hospital and Faculty of Medicine, University of Coimbra; 3000-075 Coimbra Portugal
4. Department of Dermato-Allergology, National Allergy Research Centre, Gentofte Hospital; University of Copenhagen; 2900 Hellerup Denmark