title: Nickel allergy in a Danish population 25 years after the first nickel regulation.
abstract: BACKGROUND
  Nickel in metallic items has been regulated in Denmark since 1990; however, 10% of young Danish women are still sensitized to nickel. There is a need for continuous surveillance of the effect of regulation.
  
  
  OBJECTIVE
  To identify current self-reported metallic exposures leading to dermatitis in nickel-allergic patients, and the minimum contact time needed for dermatitis to occur.
  
  
  METHODS
  A questionnaire was sent to all patients who reacted positively to nickel sulfate 5% pet. within the last 5 years at the Department of Dermatology and Allergy, Gentofte Hospital.
  
  
  RESULTS
  The response rate was 63.2%. Earrings were the foremost cause of dermatitis after the EU Nickel Directive had been implemented, followed by other jewellery, buttons on clothing, belt buckles, and wrist watches. Dermatitis reactions within 10 min of contact were reported by 21.4% of patients, and dermatitis reactions within 30 min of contact were reported by 30.7% of patients.
  
  
  CONCLUSIONS
  Nickel exposures that led to the implementation of a nickel regulation seem to persist. The durations of contact with metallic items to fall under the current REACH regulation of nickel correspond well with the results of this study.
authors.affiliation: Department of Dermatology and Allergy, National Allergy Research Centre, Herlev and Gentofte Hospital, University of Copenhagen, 2900, Hellerup, Denmark.
authors.forename: Malin G
authors.identifier: http://orcid.org/0000-0003-2092-7826
authors.initials: MG
authors.lastname: Ahlström
authors.affiliation: Department of Dermatology and Allergy, National Allergy Research Centre, Herlev and Gentofte Hospital, University of Copenhagen, 2900, Hellerup, Denmark.
authors.forename: Torkil
authors.initials: T
authors.lastname: Menné
authors.affiliation: Department of Dermatology and Allergy, National Allergy Research Centre, Herlev and Gentofte Hospital, University of Copenhagen, 2900, Hellerup, Denmark.
authors.forename: Jacob P
authors.initials: JP
authors.lastname: Thyssen
authors.affiliation: Department of Dermatology and Allergy, National Allergy Research Centre, Herlev and Gentofte Hospital, University of Copenhagen, 2900, Hellerup, Denmark.
authors.forename: Jeanne D
authors.initials: JD
authors.lastname: Johansen
mesh_terms: D000293:Adolescent; D000328:Adult; D046288:Body Piercing / Q000009:adverse effects; D002648:Child; D003020:Clothing / Q000009:adverse effects; D003257:Consumer Product Safety / Q000331:legislation & jurisprudence*; D003718:Denmark / Q000453:epidemiology; D017449:Dermatitis, Allergic Contact / Q000453:epidemiology* / Q000209:etiology / Q000517:prevention & control; D005260:Female; D006801:Humans; D055498:Jewelry / Q000009:adverse effects; D008297:Male; D008875:Middle Aged; D009532:Nickel / Q000009:adverse effects*; D057566:Self Report; D013997:Time Factors; D055815:Young Adult
chemical_list: D009532:Nickel
keywords: EU directive; allergic nickel dermatitis; metallic items; nickel; prolonged direct contact