title: Contact sensitizers in commercial hair dye products sold in Thailand.
abstract: BACKGROUND
  Hair dyes are known to contain potent contact allergens for which sensitization rates have increased over the last decade.
  
  
  OBJECTIVE
  To examine the type and frequency of potent contact sensitizers labelled on hair dyes sold in metropolitan Bangkok, Thailand.
  
  
  METHODS
  During the 2013-2014 study period, labelled ingredient information from home use and professional hair dye products was collected.
  
  
  RESULTS
  Two hundred and fifty-two hair dye products were evaluated. One hundred and forty-nine products from 48 brands were domestically produced in Thailand, and 103 products were from 23 multinational brands produced in countries other than Thailand. Two hundred and fourteen of 252 (84.9%) hair dye products were found to contain strong skin sensitizers, with 118 (46.8%) being found in domestically produced products, and 96 (38.1%) being found in multinational brand products. Thirty-eight hair dye products (15.1%) were free of potent skin sensitizers. The number of domestically produced products (31, 20.8%) that were free of potent skin sensitizers was significantly higher (p = 0.002) than the number of multinational brand products (7, 6.8%).
  
  
  CONCLUSIONS
  p-Phenylenediamine was the most prevalent potent sensitizer found among domestically produced hair dyes available on the market. Our findings indicate regional differences in hair dye allergen exposure.
authors: Contact Dermatitis Clinic, Department of Dermatology, Faculty of Medicine Siriraj Hospital, Mahidol University, 10700, Bangkok, Thailand.
authors: Waranya
authors: W
authors: Boonchai
authors: Contact Dermatitis Clinic, Department of Dermatology, Faculty of Medicine Siriraj Hospital, Mahidol University, 10700, Bangkok, Thailand.
authors: Monthathip
authors: M
authors: Bunyavaree
authors: Contact Dermatitis Clinic, Department of Dermatology, Faculty of Medicine Siriraj Hospital, Mahidol University, 10700, Bangkok, Thailand.
authors: Waranaree
authors: W
authors: Winayanuwattikun
authors: Contact Dermatitis Clinic, Department of Dermatology, Faculty of Medicine Siriraj Hospital, Mahidol University, 10700, Bangkok, Thailand.
authors: Pranee
authors: P
authors: Kasemsarn
mesh_terms: D000485:Allergens / Q000009:adverse effects / Q000032:analysis*; D003430:Cross-Sectional Studies; D017449:Dermatitis, Allergic Contact / Q000209:etiology; D006202:Hair Dyes / Q000009:adverse effects / Q000032:analysis / Q000737:chemistry*; D006801:Humans; D010655:Phenylenediamines / Q000009:adverse effects / Q000032:analysis; D011356:Product Labeling; D013785:Thailand
chemical_list: D000485:Allergens; D006202:Hair Dyes; D010655:Phenylenediamines; C029728:4-phenylenediamine
keywords: contact allergens; hair colouring; hair dye; p-phenylenediamine; sensitizer