p-Phenylenediamine and other allergens in hair dye products in the United States: a consumer exposure study

Contact Dermatitis. 2014 Apr;70(4):213-8. doi: 10.1111/cod.12164.


Background: Hair dye products constitute an important source of allergen exposure, and contribute importantly to allergic contact dermatitis in consumers and hairdressers.

Objectives: To evaluate the presence of potent contact sensitizers in oxidative hair dye products intended for home use on the US market.

Methods: Ingredient labels of 107 hair dyes from 10 major brands were examined and used to assess the prevalence of hair dye substances known to be potent contact sensitizers.

Results: One hundred and six of 107 (99%) products contained at least one potent sensitizer, and the average product contained six (range 0-11). p-Phenylenediamine (PPD) was found in 83 products (78%), but resorcinol (89%), m-aminophenol (75%), p-aminophenol (60%) and toluene-2,5-diamine (21%) were also frequently identified.

Conclusions: Potent contact sensitizers were almost universally included in the hair dyes investigated in the United States. Although PPD is a common allergen, resorcinol and m-aminophenol were found more frequently. In total, 30 potent sensitizers were found. Clinicians should consider other allergens in addition to PPD when evaluating patients with suspected hair dye allergy.

Keywords: allergens; allergic contact dermatitis; consumer product safety; exposure analysis; hair dye; market survey; p-phenylenediamine; patch testing.

MeSH terms

  • Allergens / adverse effects*
  • Aminophenols / adverse effects
  • Barbering*
  • Coloring Agents / adverse effects*
  • Dermatitis, Allergic Contact / etiology*
  • Environmental Exposure / adverse effects
  • Environmental Exposure / statistics & numerical data
  • Hair Dyes / adverse effects
  • Hair Dyes / chemistry*
  • Humans
  • Occupational Exposure / adverse effects*
  • Occupational Exposure / statistics & numerical data
  • Phenylenediamines / adverse effects*
  • Resorcinols / adverse effects
  • United States


  • Allergens
  • Aminophenols
  • Coloring Agents
  • Hair Dyes
  • Phenylenediamines
  • Resorcinols
  • 2,5-diaminotoluene
  • 3-aminophenol
  • 4-aminophenol
  • 4-phenylenediamine
  • resorcinol