Just how safe are permanent hair dyes? According to the latest reports, not very, even though the main allergen—PPD (paraphenylenediamine)—has been severely restricted in most of the popular brands.
In Europe, PPD levels are allowed to constitute 6 per cent of the total hair-dye content—except in Germany, France and Sweden, where it has been banned completely.Yet, despite its restricted use, dermatologists continue to report increasing numbers of cases of contact dermatitis. In one recent survey in London, contact dermatitis cases were found to have doubled in the past six years, and researchers are convinced that permanent hair dyes are to blame. The same clinic has confirmed such
a trend over an even longer period. Between 1965 and 1975, it would see up to 11 patients a year who had non-occupational PPD allergy (that is, they weren’t hairdressers). But, in recent years, that figure has increased to 40 cases each year.
There’s been a similar trend reported in Belgium and Portugal, as well as in Denmark, and Germany, despite the PPD ban.The problem is far worse in the Far East, where hair dyeing is extremely popular, and where they use brands that don’t have a PPD restriction. One study in Thailand has reckoned that more than one million adults may be sensitive to PPD (BMJ, 2007; 334: 220).