title: Exposures and reactions to allergens among hairdressing apprentices and matched controls.
abstract: BACKGROUND
  Early and extensive exposures to chemical substances such as are found in hair dyes, perfumes and nickel are known risk factors for allergic reactions. Hairdressing apprentices belong to a high-risk group, as they are exposed both occupationally and personally.
  
  
  OBJECTIVE
  To estimate the degree of exposure and adverse skin reactions to chemical substances in a cohort of hairdressing apprentices, at the start of their education, as compared with a matched sample from the general population.
  
  
  METHODS
  During their first 2 weeks of training, 382 hairdressing apprentices were enrolled in this study. All apprentices completed a self-administered questionnaire that included questions regarding, for example, exposures and skin reactions to hair dye, perfumed products, and piercings. For comparison, the questionnaire was sent to a control group from the general population, matched on age, sex, and postal code (n = 1870).
  
  
  RESULTS
  Within the previous year, 95.2% of hairdressing apprentices and 66.9% of the control group had dyed their hair (p < 0.001); the apprentices dyed their hair, on average, 6.6 times per year, as compared with 3.7 times per year in the control group (p < 0.001). The mean age of the first hair dying among the apprentices was 12.1 years, as compared with 13.3 years for the matched control group (p < 0.001). The hairdressing apprentices reported more eczematous reactions to hair dye (p = 0.002) than the controls. Semi-permanent so-called 'black henna tattoos' had been carried out in 48.1% of the apprentices, as compared with 31.0% of the controls (p < 0.001).
  
  
  CONCLUSIONS
  Both hairdressing apprentices and the matched control group of young people from the general population were highly exposed to potent allergens. The hairdressing apprentices were even more exposed to products containing hair dye substances and piercings, and reported more adverse reactions to hair dye products than their matched controls from the general population.
authors.affiliation: Research Centre for Hairdressers and Beauticians, Department of Dermato-Allergology, Copenhagen University Hospital Gentofte, DK-2900 Hellerup, Denmark. annbre03@geh.regionh.dk
authors.forename: Anne
authors.initials: A
authors.lastname: Bregnhøj
authors.forename: Heidi
authors.initials: H
authors.lastname: Søsted
authors.forename: Torkil
authors.initials: T
authors.lastname: Menné
authors.forename: Jeanne Duus
authors.initials: JD
authors.lastname: Johansen
mesh_terms: D000293:Adolescent; D000328:Adult; D001505:Beauty Culture; D046288:Body Piercing / Q000009:adverse effects / Q000706:statistics & numerical data; D017449:Dermatitis, Allergic Contact / Q000453:epidemiology*; D004485:Eczema / Q000139:chemically induced* / Q000453:epidemiology*; D005260:Female; D006197:Hair; D006202:Hair Dyes / Q000009:adverse effects; D006801:Humans; D008297:Male; D009532:Nickel / Q000009:adverse effects; D010476:Perfume / Q000009:adverse effects; D016016:Proportional Hazards Models; D011795:Surveys and Questionnaires; D013653:Tattooing / Q000009:adverse effects / Q000706:statistics & numerical data; D055815:Young Adult
chemical_list: D006202:Hair Dyes; D010476:Perfume; D009532:Nickel