What Everyone Needs to Know about the Hair Dye Chemical PPD

There have been recent reports in the news of women having serious reactions to a specific ingredient found in some hair dyes.  The ingredient is paraphenylenediamine or “PPD” for short.  Many patients have asked me about these articles appearing in various newspapers reports.

PPD is commonly found in permanent and semi-permanent hair dyes. It is used to help give a hair dye a dark color that doesn’t easily wash out.  PPD also gives hair dyes a natural, realistic color. My previous blog reviewed the topic of hair dye allergy.

Despite making the news recently, there is nothing new about allergic reactions to PPD.  It is well known that PPD can cause some sort of allergic reactions in about 5% of users. These allergic reactions vary from skin rashes & blisters (a phenomenon called allergic contact dermatitis)  to hives (a phenomenon called contact urticaria) to serious anaphylactic reactions and rarely even death.  Reactions can occur as a few days to a week or more after application of a hair dye.  These reactions tend to occur on the second, third or fourth application rather than on the very first. 

Health Canada has banned the use of PPD in cosmetic products that are applied directly to the skin.  For example, PPD is banned in black henna tattoos which are sometimes known as holiday tattoos because vacationers may have these dark richly pigmented tattoos applied while enjoying a vacation.  However, PPD is not banned in hair dyes.  PPD is allowed in hair dyes provided the product labelling contains a warning about possible allergic reactions. On its website, Health Canada states

PPD is an acceptable ingredient for use in hair dyes that are rinsed off after a maximum of 30 minutes. When used correctly, hair dye does not come directly into contact with skin for prolonged periods of time.

Allergic reactions to PPD include red skin rashes, itching, blisters, open sores, and scarring within 2 to 10 days following application. These allergic reactions may also lead to sensitivities to other products such as hair dye, sun block and some types of clothing dyes.

My general advice for individuals considering dyeing their hair:

1) Read the instructions on the package carefully.  If there are no instructions, don't buy the product.

2) Be sure to do a "patch test". Apply a small amount (size of a penny) to an area on the skin. An area such as behind the ear or on the forearm is a particularly good spot.

3) Let it dry.

4) If immediate redness develops, the individual may be 'irritated' by the product. This usually does not indicate an allergy. 

5) Wait 72 hours (3 days) and do another check of the area where the dye was applied.

6) If there is no reaction, then the test is said to be "negative". Individuals who have a "negative" test are unlikely to develop an allergic reaction when they use a hair dye. 

7) If the individual develops redness, scaling and/or blisters in the area where the patch test was applied, they may be truly allergic to the PPD chemical.  Use of the hair dye is not recommended. Take a picture of the reaction. Make an appointment with a physician knowledgeable about hair dye allergy to discuss further.

8) In general, semi-permanent dyes have less PPD than permanent dyes, so try to use them first to see if you can achieve your desired color.  To even further reduce your exposure to PPD, try to use  the lightest color possible. Highlights or low lights can be used too because these don't touch the scalp. Consider experimenting with natural colors, which don’t contain PPD.