Hair Dye Allergies – Introduction
About 5% of permanent hair dye users develop an allergy, mostly in the form of an allergic contact dermatitis with a redness and itch in the head area. A systemic reaction with an involvement of the whole body skin and other organs, although rare, is possible in severe cases (1). Understandably dermatitis of the hands affects many hair stylists who are making bare skin contact with these dyes. (2). The main cause implicated in hair dye allergies, whether on the scalp, face, neck, back or hands, is a substance commonly known as PPD. The most common symptoms is an itchy scalp or burning of the scalp within a short period of time after applying the dye. Sometimes symptoms may develop days or weeks after the hair dye treatment.
PPD (4-ParaPhenyleneDiamine, C6H8N2)
PPD is widely available on the market since 1909, and it is still used in over 2 out of 3 of permanent hair dyes (2007). Commercial hair dye products typically come in two bottles - the one with PPD-based dye (non-oxidized and thus colorless) and the other with oxidizer or developer, usually hydrogen peroxide (H2O2). In the hair dying process, the peroxide is initially used to break down the natural skin and hair pigment known as melanin. Then the PPD is used to replace the hair color. When PPD reacts with peroxide, it becomes partly oxidized and colored – it is this form that it may cause an allergy. Fully oxidized PPD does not cause an allergy, so PPD sensitive persons can safely wear fur coats dyed with PPD (3). PPD can be also found in some dark colored cosmetics and temporary tattoos. In France, Germany and Sweden, PPD was banned as a hair dye because it is believed to have serious toxic effects on and in the human body (4).
Alternative names for PPD: PPDA, Orsin, Rodol, Ursol.
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