Paraphenylenediamine

Allergic contact dermatitis does exactly what it says on the tin. It’s an itchy skin rash caused by contact with something that your body doesn’t like. Unfortunately, as technology advances our bodies are coming into contact with an increasing number of new things and not surprisingly they are not all friendly.

Paraphenylenediamine is not exactly new but it is a product of our modern age. More conveniently known as PPD, it is a chemical that is widely used in dyes. It is a colourless substance that requires oxygen for it to become coloured, and it is this partially oxidised state that can cause an allergic reaction in sensitive individuals.

It may be found in textiles, fur, rubber, cosmetics and shoes. It is very popular as a hair dye because it is permanent, gives a natural look and the hair can be shampooed or permed without any decolouring or damage. Inevitably hairdressers will come into regular contact with PPD and are therefore vulnerable to allergic reactions.

Allergy to PPD is usually confirmed by a patch test which involves placing a small amount on a patch of skin and waiting 48-72 hours to see if it causes any irritation. If you know you are allergic to PPD it is best to avoid all oxidation type hair dyes. These are usually recognised by coming in a 2-bottle presentation.

There is also a chance that you may be allergic to substances related to PPD. These include Azo dyes and some medicines such as sulphonamides which are used as antibiotics and some local anaesthetics. So always tell your doctor, dentist or pharmacist that you are allergic to PPD. And if you check the contents of a product for PPD you need to know that it comes in many different guises.

The following are all alternative names for PPD: PPDA; Phenylenediamine base; p-Phenylenediamine; 4-Phenylenediamine; 1,4-Phenylenediamine; 4-Benzenediamine; 1,4-Benzenediamine; para-Diaminobenzene (p-Diaminobenzene); para-Aminoaniline (p-Aminoaniline); Orsin™; Rodol™; Ursol™.

Information written by the talkhealth medical panel

Last Reviewed: 28 March 2011
Next Review Date: 18 October 2012