title: Association between cobalt allergy and dermatitis caused by leather articles--a questionnaire study.
abstract: BACKGROUND
  Cobalt is a strong skin sensitizer and a prevalent contact allergen. Recent studies have recognized exposure to leather articles as a potential cause of cobalt allergy.
  
  
  OBJECTIVE
  To examine the association between contact allergy to cobalt and a history of dermatitis resulting from exposure to leather.
  
  
  METHODS
  A questionnaire case-control study was performed: the case group consisted of 183 dermatitis patients with a positive patch test reaction to cobalt chloride and a negative patch test reaction to potassium dichromate; the control group consisted of 621 dermatitis patients who did not react to either cobalt or chromium in patch testing. Comparisons were made by use of a χ(2) -test, Fisher's exact, and the Mann-Whitney test. Logistic regression analyses were used to test for associations while taking confounding factors into consideration.
  
  
  RESULTS
  Leather was observed as the most frequent exposure source causing dermatitis in the case group. Although the case group significantly more often reported non-occupational dermatitis caused by leather exposure (p < 0.001), no association was found between cobalt allergy and dermatitis caused by work-related exposure to leather.
  
  
  CONCLUSIONS
  Our study suggests a positive association between cobalt allergy and a history of dermatitis caused by non-occupational exposure to leather articles.
authors.affiliation: Department of Dermato-Allergology, National Allergy Research Centre, Copenhagen University Hospital Gentofte, Hellerup, 2900, Niels Andersens Vej 65, Denmark.
authors.forename: David
authors.initials: D
authors.lastname: Bregnbak
authors.forename: Jacob P
authors.initials: JP
authors.lastname: Thyssen
authors.forename: Claus
authors.initials: C
authors.lastname: Zachariae
authors.forename: Torkil
authors.initials: T
authors.lastname: Menné
authors.forename: Jeanne D
authors.initials: JD
authors.lastname: Johansen
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000485:Allergens / Q000009:adverse effects*; D016022:Case-Control Studies; D003035:Cobalt / Q000009:adverse effects*; D003430:Cross-Sectional Studies; D017449:Dermatitis, Allergic Contact / Q000209:etiology*; D009783:Dermatitis, Occupational / Q000209:etiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010328:Patch Tests; D011788:Quality of Life; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires; D013633:Tanning; D055815:Young Adult
chemical_list: D000485:Allergens; D003035:Cobalt; C018021:cobaltous chloride
keywords: allergic cobalt dermatitis; allergy; cobalt; cobalt allergy; cobalt chloride; dermatitis; leather; metals