Hair dye and allergens.

There have been a lot of articles lately about allergic reactions to hair dye; specifically to one ingredient in the dye. PPD, or Para-phenylenediamine, is a known allergen and is banned from use in make-up but not hair colour. As Sali Hughes points out in her article on this subject, it is used in 99% of permanent dyes, newsprint, black clothing and permanent make-up. It's not in eyeliner and mascaras.

PPD is used because it is extremely successful at fixing colour in grey hair. Temporary colours do not cover grey.

When a dye manufacturer claims to be PPD free, they use PTD (Paratoluenediamine) instead which is structurally similar to PPD and causes the same reactions in those who have already had a bad reaction to the latter.

There is a company (I'm not naming them here) who says that none of their products contain PPD. Instead, they say that they use a compound called Toluene 2, 5- Diamine Sulfate. After a lot of googling, I've discovered that this compound is PTD. Company N prides themselves on using this as a safe alternative to PPD but, convieniently not stating that it is of the same family and thus causes similar reactions.

Some companies are now formulating dyes that have lower levels of these chemicals and thus less of a worry of a reaction. Sali refers to one such company in her article - Organic Color Systems.

If you are worried about severe reactions to your dye, always do a patch test but be aware that just because the test shows no reaction, it still may cause a reaction when you come to colour your whole head.

When buying a dye, check the ingredients list first for PPD and PTD. As a reference, keep a note in your handbag of the chemical names and abbreviations. PTD - Toluene 2, 5- Diamine Sulfate and Paratoluenediamine. PPD - Para-phenylenediamine.

If you get your hair coloured at a salon, ask for a patch test to be done beforehand and ask if the dyes contain these chemicals. In general, the darker the colour, the more PPD there will be.

A lot of people will go through life without ever having an allergic reaction to their dye. It's just good sense to be informed about these things in case the worst happens.