1. Department of Allergy and Clinical Immunology; 424 General Military Training Hospital; Thessaloniki; Greece
2. Ambulatorio di Allergologia; Clinica San Carlo; Paderno Dugnano; Millan; Italy
3. Department of Allergy; Clinica Universidad de Navarra; Pamplona; Spain
4. Department of Dermatology and Allergology; University Medical Center Utrecht; Utrecht; The Netherlands
5. Department of Dermatology and Allergy; Charité - Universitätsmedizin Berlin; Berlin; Germany
6. Department of Dermatology and Allergy; Hannover Medical School; Hannover; Germany
7. Allergy Unit; Department of Dermatology; University Hospital; Zurich; Switzerland
8. Department of Dermatology; Odense University Hospital; Odense Area; Denmark
9. Department of Dermatology; St John's Institute of Dermatology; London and Norfolk and Norwich University Hospital; Norwich; UK