An overview of hair dye safety

Summary Background  Due to their basic reactive chemistry, the safety evaluation of hair dyes has always been a major consideration. Hair dyes are therefore one of the most studied and regulated consumer products on the market with an overwhelming amount of safety data. Yet, hair dyes continue to come under scrutiny, primarily regarding two safety concerns: First, a potential link to increased cancer risk, and second, skin allergy. Aims  This paper will review epidemiologic studies regarding hair dye safety, discuss hair dye allergies incidence and consumer practices, and provide practical recommendations for dermatologists and patients. Conclusion  Numerous epidemiologic studies have been conducted, evaluating a potential correlation between hair dye use and an increased risk for any possible cancer type. Taking all currently available epidemiology studies and state‐of‐the‐art safety data into account, it is concluded that hair dyes do not pose an increased cancer risk, either for consumers and clients, or for professional hairdressers. Like other products such as certain foods or drugs, hair dyes can cause allergic reactions in a few sensitive individuals. The vast majority of hair dye allergies are delayed hypersensitivity or type IV reactions. Allergic reactions to hair dyes are rare when compared to their widespread use and occur at a rate of approximately 1 per 1 million products sold. To further minimize the risk of hair dye allergies, the cosmetic industry has voluntarily implemented risk management measures. For example, all oxidative hair dye products bear allergy warning labels on pack, making consumers and hairdressers aware of a potential allergy risk. In addition, hair coloring products are equipped with clear use instructions and the majority of brands recommend conducting a skin sensitivity test 48 h before the hair coloration. Finally, professional hairdressers are advised to apply appropriate occupational safety measures (like wearing gloves). In collaboration with dermatologists, we will continue the education efforts towards consumers, clients, and hairdressers to improving the compliance with the risk management measures with the overall aim to further minimize any potential allergy risk.