In January of this year, the UK's popular press reported that 19-year-old Crystal Atkinson is planning to sue cosmetic giant L'Oreal over claims that a hair dye caused her skin to peel and her ears to swell to three times their size. The teenaged mother alleges that she suffered burns to her face, neck and scalp, and a rash over her entire body, after using L'Oreal's Garnier Nutrisse chestnut brown hair dye-despite experiencing no reaction to the skin allergy test she carried out 48 hours before using the product.
A similar incident occurred last year to 16-year-old Stacy Ditroia. In her case, she suffered severe swelling of the head and neck, struggled to breathe, and had to be taken to hospital after dying her hair choco-late brown. Again, a L'Oreal hair colouring product was to blame.
Although L'Oreal, in both cases, was quick to reassure consumers that allergies to hair colorants are "extremely rare", new research shows that hair dye allergy is, in fact, on the rise, particularly among young people. European dermatologists point out that more and more people around the world are dyeing their hair, and are doing so at a younger age. As a result, the frequency of allergic reactions to hair dye is increasing (BMJ, 2007; 334: 220).
The main culprit, they say, is the common chemical ingredient used in permanent hair dyes called para-phenylenediamine, or PPD. It's found in more than two-thirds of hair dyes currently on the market, including many of the top-selling brands. The compound is an effective colorant because of its low molecular weight, its ability to penetrate the hair shaft and follicle, and its strong protein-binding capacity. However, these properties also make PPD an ideal-and potent-contact allergen.
In fact, over the past several decades, allergic reactions to PPD became such a serious problem that the chemical was banned completely from hair dyes in Germany, France and Sweden. Current European legislation allows PPD to comprise up to 6 per cent of the constituents of commercial hair dyes.
Yet, despite this restricted use, dermatologists continue to report increasing numbers of cases of PPD-induced contact dermatitis. A survey of adults in a London clinic found that cases have doubled over the past six years, and it's likely that the increased personal use of hair dye is to blame. The same clinic confirmed that, during 1965-1975, it saw up to 11 patients a year with non-occupational (they weren't hairdressers) PPD allergy, whereas now that figure has grown to more than 40 cases annually. This trend has also been observed in other countries (BMJ, 2007; 334: 220).
A patient with contact allergy to hair dye often presents with a simple rash on the face or around the hairline. But severe reactions are also seen. One consumer complaint-based study in Denmark identified 55 cases of severe acute contact dermatitis caused by hair dye, with gross swelling of the face, scalp and ears. These cases were responsible for 75 visits to the health service and five admissions to hospital, leading the researchers to conclude that PPD, at its current concentrations in hair dye, "presents a significant health risk for the population" (Contact Dermatitis, 2002; 47: 299-303). Severe hair-dye reactions among children have also been reported (Contact Dermatitis, 2006; 54: 87-91).
According to the latest research, even hair dyes containing relatively small concentrations of PPD can be a problem, as the chemical accumu-lates in the skin over time. This means that intermittent exposure to lower levels of PPD, such as from regular hair dyeing, may elicit the same reaction as a one-off exposure to a higher concentration (Contact Dermatitis, 2007; 56: 262-5).
Another PPD problem is cross-sensitization. This means that once you have reacted to PPD, you may become sensitive to its chemical cousins. This includes other types of hair dye, textile dyes, pen ink, food dyes, medication dyes, preservatives (parabens) and some drugs (such as benzocaine, procaine and sulphon-amides). So, an allergy to PPD is a lifelong problem (Frosch PJ et al., eds. Contact Dermatitis, 4th edn. Springer, 2006: 479).
Sensitization to PPD has also been seen with its use as a skin paint for temporary tattoos involving black 'henna' (J Cosmet Dermatol, 2003; 2: 126-30). Interestingly, PPD is not permitted for this type of use. As the US Food and Drug Administration (FDA) states, it is not approved for direct application to the skin (www. cfsan.fda.gov/~dms/cos-tatt.html). However, when hair dye is applied, it inevitably comes into direct contact with the scalp and skin on the fore-head and around the ears. So the fact that it triggers allergic reactions in some people is hardly surprising.
As informed readers will know, however, allergic reactions are not the only problem associated with hair dyes. Although controversial, a mounting body of evidence links hair-dye use to several types of cancer, including rare cancers such as non-Hodgkin's lymphoma (NHL).
Health problems among hair-dye users, particularly of the black, dark-brown or red shades, were first noted in the late 1970s, when several studies found links between hair dyes and breast cancer (NY State J Med, 1976; 76: 394-6; J Natl Cancer Inst, 1979; 62: 277-83). Women who started dyeing their hair at age 20 had twice the risk of 40-year-olds. The users at greatest risk were those aged 50-79 who had been dyeing their hair for years. Also, compared with women who had never used hair dyes, those who dyed their hair five or more times a year had twice the risk of developing ovarian cancer (Int J Cancer, 1993; 55: 408-10).
It was also discovered that people who had worked for 10 or more years as hairdressers or barbers had a fivefold greater risk of bladder cancer than the general population (Int J Cancer, 2001; 91: 575-9).
However, it's the link with other-wise unusual cancers that provides the most compelling evidence of hair-dye toxicity. Dyeing your hair can increase the risk of non-Hodgkin's lymphoma (NHL) and multiple myeloma from two to four times over a non-user's risk (Am J Public Health, 1988; 78: 570-1; J Natl Cancer Inst, 1994; 86: 210-5). Indeed, hair dyes may account for as much as 20 per cent of all cases of NHL in women (Cancer Res, 1992; 52 [19 Suppl]: 5496s-500s).
Hair dye use has increased dramatically among men, too, over the last few decades. Studies show that hair colorants may be respons-ible for a 90-per-cent greater risk of multiple myeloma among men (Am J Public Health, 1992; 82: 1673-4), and nearly twice the risk of NHL and leukaemia than among non-users (Am J Public Health, 1988; 78: 570-1).
Nevertheless, there are studies that dispute the cancer risk of hair dyes. Indeed, as a 1993 report by the International Agency for Research on Cancer (IARC) concluded, "There is inadequate evidence that personal use of hair colorants entails expos-ures that are carcinogenic". However, the report also stated that being a hairdresser or barber entails exposures that are "probably carcino-genic", suggesting that hair dyes may well lead to cancer.
The problem may lie with the older hair-dye formulations, which were considerably more toxic. One study found an increased risk for NHL in women who used permanent, intense hair colourings (black, dark brown and dark blonde) before 1980, but no risk for men or women who began using these products after that time (Carcinogenesis, 2007; 28: 1759-64).
However, the researchers admit that this finding may be because "insufficient time has passed for the induction/latency period". In fact, chemically induced cancers typically take more than 20 years to develop (Crit Rev Toxicol, 2007; 37: 521-36). So, it may not be that the new dyes don't cause cancer, but just that it's too soon to tell.
Although there are now restrict-ions on a number of ingredients, the current hair-dye formulations still use a cocktail of toxic chemicals that can rapidly penetrate the skin, and are carcinogenic and mutagenic to both animals and humans. PPD, for example, has also damaged DNA in test-tube studies (Toxicol Lett, 2007; 170: 116-23), while 4-aminobiphenyl, another current hair-dye ingredient, is known to cause bladder cancer (Chem Res Toxicol, 2003; 16: 1162-73).
According to Skin Deep, a 2004 study and ranking of 7500 cosmetic products, published by the US non-profit Environmental Working Group (EWG), 69 per cent of hair-dye products may pose cancer risks (www.thegreenguide.com/doc/110/hair). More recently, in an assessment of 15,000 cosmetics and personal-care products, EWG researchers found that 82 per cent of hair dyes and bleaching products were contamin-ated with the cancer-causing 1,4-dioxane (see www.ewg.org/node/ 21286 for more details).
And if that's not enough to put you off dyeing your hair for good, take a look at the EWG's searchable cosmetics-safety database (www. cosmeticsdatabase.com). Many of the most popular hair-dye products have a hazard risk of 10 out of 10.
If you live in Europe, you're better off than in the US. In 2006, the Europ-ean Commission banned 22 hair-dye agents that could potentially cause bladder cancer if used long term. At present, a further 49 ingredients are under consideration for such a ban. However, a quick glance at the labels of some of the products now on the shelves indicates that there's still cause for concern and, as usual, it's up to the consumer to be vigilant and select the safest products available (see box above). Alternatively, maybe it's time to ditch the dye and go with the natural look.
Safer hair colouring
- Always do a patch test first. Hair-dye makers maintain that allergic reactions can be avoided if instructions are carefully followed and a skin-sensitivity test carried out 48 hours before product use. Indeed, the allergy test used by brands like L'Oreal appears to be 100-per-cent predictive (Eur J Dermatol, 2005; 15: 18-25; Eur J Dermatol, 2002; 12: 322-6). However, bear in mind that patch-testing is not always fail-safe (Br J Dermatol, 2007; 157: 1017-20), particularly as there are so many potential allergens in hair dyes besides PPD, the most commonly used allergy marker (Contact Dermatitis, 2004; 51: 241-54).
- Read the label. Use the safer alternatives currently on the market (see www.safecosmetics.org for companies that have pledged not to use chemicals that are known to, or strongly suspected of, causing cancer, mutations or birth defects in their products). Avoid products that contain phenylenediamines like PPD, which includes many so-called 'natural' hair colours (see PROOF! vol 8 no 1). Look out for words like 'amino' or 'nitro' and names of colours starting with the letters 'HC', which indicate that it's not natural. Use the EWG database at www.cosmeticsdatabase. com to help figure out which ingredients and products to avoid.
- Don't dye your hair too often. Leave the maximum amount of time between colour applications.
- Apply dye to the hair, not to the scalp. You can now buy hair-dye applicators, which look like hollow combs or brushes, that allow you to smooth the dye onto the hair with minimum contact with the scalp. Also, leave hair dyes on the head for the minimum required time.