**6. Acknowledgment**

We would like to thank the following individuals and associations for their collaboration, teaching and daily efforts, as well as for the material provided: the European Society of Contact Dermatitis (ESCD), the Dermatology Workgroup of the European Academy of Allergy and Clinical Immunology (EAACI), the Skin Allergy Committee of the Spanish Society of Allergology and Clinical Immunology (SEAIC), especially Dr. Pilar Iriarte Sotés (Arquitecto Marcide - Profesor Novoa Santos Hospital Complex, Ferrol, Spain); and the Spanish Workgroup on Contact Dermatitis (GEIDC) of the Spanish Academy of Dermatology and Venereology (AEDV). Their final input was crucial for the preparation of this manuscript.
