The August 2026 edition of Pubmed journal relates the case of a woman who had a severe anaphylactic reaction to a hair dye, despite having used the product safely four months prior. She had also tested negative in a skin test performed before colour application.
Despite these precautions, a few minutes after applying the hair dye, the woman had hives all over her body, nausea, swelling, and trouble breathing. Medical personnel were required to treat her for a life-threatening allergic reaction. Indeed, experts warn that previous tolerance does not indicate future safety.
Toxic components
Chemical hair dye is a complex formulation. The colouring agents such as PPD (p-phenylenediamine)or TDA/PTDS (toluene-2,5-diamine) are activated by oxidising agents such as hydrogen peroxide. Both components are allergenic and may contain additional substances with allergenic potential. Cross-reactions between the two are also possible.
The use of PPD in hair colour formulations is still common despite its increasingly toxic reputation. Manufacturers often use toluene-2,5-diamine as an alternative to it, claiming “PPD-free” to appeal to consumers, who assume the substitute is safe to use. This is why the American Contact Dermatitis Society named the sulfate form of toluene-2,5-diamine the 2025 Allergen of the Year to raise awareness of its toxicity.
Allergies to hair dyes usually appear a day or two after application and can vary across itching, redness and swelling. While immediate whole-body reactions are rare, they can occur suddenly after years of uneventful use.
Hairstylists: an endangered profession?
Hairstylists appear to be most directly impacted by the toxicity of hair colours. Almost one in five are at risk of developing a health issue. The International Agency for Research on Cancer (IARC), a World Health Organization panel, states that regular exposure to hair dyes, processing agents and other chemicals used by hairstylists probably increases their cancer risk.
Studies have shown that hairstylists have significantly more miscarriages and risk of infertility. According to the American Journal of Epidemiology, those who have worked with chemical hair dye for over five years also have triple the risk of developing breast cancer. Hairstylists are also more likely to develop respiratory diseases, and studies suggest an overwhelming 70% will develop some form of dermatitis.
Hair colour remains high in demand
Despite the potential health risks, the demand for hair colour continues unabated. According to Garnier’s Hair Colour Insights Report, a massive 85% of people in the UK dye their hair, either at home or in the salon. The study also shows that younger people are colouring their hair, at ages ranging from 25 to 34 years, before gray hair typically becomes visible.
Growing demand for healthier alternatives
Hairstylist Victoria of the Curly Cow salon in Bolton says “coming into contact with harsh chemicals always felt like part of the job”. She suffers from acute dermatitis, and this has pushed her to search for other healthier alternatives. While her salon still offers traditional chemical colour for those clients who want to continue with it, she herself will only apply safe and clean alternatives.
Cancer survivors Sarah and Kimberly in Wrexham have created the Aura Holistic Hair and Beauty salon, vowing to use only 100% plant hair colours containing no chemicals at all. According to Sarah, “Cancer rarely has one simple cause, and it is impossible to identify every individual exposure. But the recognised health risks within our industry are real – and I no longer feel comfortable ignoring them.” She says her purpose today is to show her clients that alternatives exist for a more health and safety conscious approach to hair care.
Too few salons in the UK today offer these clean options, and many stylists are afraid of endangering their business by switching to natural techniques of hair colour, very different from the chemical colours they were trained in. Still, as customers become increasingly aware of the health risks, many will ask for truly clean and safe products. Hopefully that will encourage the industry to change as well.
