Researchers at St John's Institute of Dermatology in London have warned that allergic hair dye reactions are on the increase as more people colour their hair. This especially affects young people, who are more likely to dye their hair regularly. Agents that can cause allergic reactions - such as para-phenylenediamine (PPD) - are contained in more than two-thirds of hair dyes, a paper published in the British Medical Journal warns, and can lead to facial dermatitis and facial swelling in severe cases.
Current EU legislation states that PPD should comprise up to 6% of hair dye constituents, but France, Germany and Sweden have already banned PPD from hair dyes after allergic reactions became a severe problem. Yet the researchers warn that there is no alternative to these agents available for use in permanent hair dye.