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Health Risks of Chemical Hair Dyes

Discussion in 'Dermatology' started by Hala, Feb 23, 2014.

  1. Hala

    Hala Golden Member Verified Doctor

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    Over 50 million women in the US dye their hair regularly. Many more say they will once they start to turn gray, and many girls use hair dyes from an early age. However, there are risks associated with using these products. One of the main chemicals in most hair dyes was once banned in several European countries, and hair dye chemicals have been shown to have a variety of harmful effects in scientific experiments. Use of hair dye has been linked to allergic reactions, respiratory disorders and even cancer.


    Hair Dyes Can Cause Allergic Reactions


    Skin and other allergic reactions pose the biggest risk to hair dye users. It's difficult to say how many hair dye users suffer from allergic reactions, as most do not seek medical attention. However, there are many cases where allergic reactions to hair dyes have been severe or even fatal.


    Signs of a mild reaction may only be irritation of the upper eyelids or rims of the ears, but in more severe reactions, the whole head or body may be involved.


    A severe form of allergic reaction is anaphylactic shock. When this occurs, the mouth and tongue swell and the airways constrict. Anaphylaxis can be rapidly fatal, and there have been isolated cases of hair dyes causing anaphylactic shock.


    Skin reactions can occur on a person's first exposure to hair dye, or can suddenly occur in a person who has been using them long-term. A patch test before every dyeing is important to help detect skin allergies, but very time dye is applied to the skin, the immune system may become sensitized, increasing the risk of future allergic reaction.



    Hair Dyes Can Cause Asthma


    Hair stylists are at risk of developing occupational asthma, both from the persulfates used in bleaches and PPD from hair dyes. Long term exposure sensitizes the airways, leading to asthma attacks on exposure to the chemicals.


    A number of studies have confirmed that hair stylists have higher levels of asthma than the general population.


    Are Hair Dyes Related to Development of Cancer?


    Cancers develop due to a combination of many factors damaging the DNA of a cell in the body. While there is proof that hair dye chemicals do cause cancer in laboratory animals at high doses, it is still debated whether the low doses from hair dyes are sufficient to cause cancer in humans.


    Many studies have been conducted to try to determine whether long-term hair dye use causes cancer, and it is still a controversial subject. Most studies have focused on a possible increased risk of bladder cancer. Some studies have found that women who had consistently used hair dye long term had higher levels, and other studies did not. Many official bodies have determined that the evidence so far is inconclusive.


    However, new studies have linked hair dye use to development of a specific type of cancer, non-Hodgkin's lymphoma (Zhang et al, 2008). This study looked at groups of women suffering from this disease, and a control group. It was found that women who started using hair dye, particularly darker colors, before 1980 had an increased risk of developing the disease.


    The strongest evidence that hair dyes can cause cancer in humans comes from studies of cancer rates in hairstylists. One study found that if a hairstylist had used hair dyes at work for 5 years or more, she had a three times higher risk of developing breast cancer. Other studies have consistently found that hair colorists have an increased risk of non-Hodgkin's lymphoma, multiple myeloma and leukemia.


    Excessive Dyeing Damages Hair

    If hair has been dyed many times, it becomes 'over-processed', which leads to brittle, dry hair that lack shine. Since hair only grows slowly (about 1.5cm/half an inch a month) longer hair can end up receiving multiple dye treatments. If other chemicals such as hair relaxers are used, the damage can be even worse, and over-processed hair easily breaks and splits.


    Unfortunately, there is really no solution to hair damage from dyeing, other than to stop dyeing. If you do not want to stop, using a deep conditioner and products specifically for dyed hair can help reduce the damage and also maintain your color. Try to dye only your roots, to reduce the number of times the length of your hair is dyed. Since your hair grows from the roots, the ends are obviously the oldest part of your hair and will accumulate damage.


    P-Phenylenediamine, PPD: the Chemical that causes Allergic Reactions

    P-Phenylenediamine (PPD) is present in over 2/3 of chemical hair dyes, and is known to be toxic to the immune system, skin, nervous system, respiratory system, liver and kidneys. It is the most toxic chemical in hair dyes. The European Union classifies it as a toxin and irritant that is dangerous in the environment. In Canada, its use in cosmetics is restricted and it was a one time banned in France, Germany and Sweden. However, it is now legally used throughout the EU.


    The Other Chemicals in Hair Dyes and Associated Risks


    • Resorcinol
    Resorcinol receives a rating of 8 (out of 10) for hazard at the Cosmetics Safety Database. It is classified by the European Union as harmful, irritant to eyes and skin and dangerous for the environment.


    It has been shown to disrupt hormonal function in rats, causing hypothyroidism (thyroid hormone deficiency), but the levels necessary were far higher than those in hair dyes (Welsch, 2008). However, autism may be caused by babies experiencing hypothyroidism while still in the womb (Roman, 2007), and there have been cases of pregnant women losing their babies after taking resorcinol by mouth (Duran et al, 2004). Resorcinol is also a skin sensitiser (Basketter et al, 2007), although it is much less potent than PPD.


    • Ammonia
    Ammonia is irritant to the skin, eyes and respiratory system, and can cause asthma and breathing difficulties. However, it is much less toxic than PPD, and only receives a rating of 3 out of 10 for toxicity at the Cosmetics Safety Database.


    • Persulfates

    Sodium, potassium and ammonium sulfates are present in hair dyes and bleaches, and are used in concentrations of up to 60%. However, concentrations of only 17.5% have been shown to irritate skin, and persulfates are also toxic when the fumes are inhaled, causing asthma and lung damage (Pang and Fiume, 2001). However, the Cosmetic Ingredient Review Expert Panel has concluded that they are safe for occasional use, provided that the skin is rinsed well after.


    • Hydrogen Peroxide
    Hydrogen peroxide is used in hair bleaches. It is corrosive, and has been banned from cosmetic use in Japan and restricted in Canada. Animal studies have shown it has toxic effects on the nervous system, respiratory and digestive systems at low doses (1974). Other studies on animals have also shown that hydrogen peroxide can damage DNA, possibly leading to cancer.


    • Lead acetate
    This is present in some hair coloring products used for gradual darkening, and is another potentially toxic chemical.Lead has well-known damaging effects on the brain and nervous system.



    Hair Dyes Marketed as 'Natural'


    Boxed, chemical hair dyes marketed as 'natural' typically do not contain resorcinol, ammonia or peroxide. However, they still contain at least some PPD, just a lower level. Lower levels are obviously better, but using these dyes does not completely remove the risk of suffering an allergic reaction or other side effect. 'Natural' hair dye manufacturers include Naturtint and Herbatint. Always look at the ingredients of any 'natural' hair dye to check out just how 'natural' it is, and check for the presence of the chemicals listed above.


    Minimizing the Health Risks if you Do Dye your Hair


    If you are really unhappy with your hair color and want to continue or start dyeing your hair, there are some ways of minimizing the potential health risks.


    Use the lightest shade possible

    First, darkest color hair dyes carry the most risk, due to the types of chemicals they contain. Do you really want a very dark shade? If you are covering gray, remember that as we age, our skin tone changes, and so even if your hair was naturally very dark when you were young, that very dark shade may no longer suit you. Often, a very dark shade on an older person can make their skin look washed out, and a lighter, warmer shade would suit them better and actually make them look younger than their original dark shade. Hair colorists will be able to advise you on the best shade for your skin tone.


    Dye as infrequently as possible

    Second, minimize your exposure and damage to your hair by dyeing it as infrequently as possible. When you do dye, make sure you always wear the gloves provided in a home kit, and while dyeing your roots, try not to rub the dye into your scalp. Make sure your bathroom is well ventilated to reduce the dye fumes you breathe in. Maybe you could just have highlights/lowlights? These may be able to be done less frequently.


    Investigate to see if there are any more natural alternatives

    Finally, investigate some of the more natural, less chemical hair dyes available on the market today! Look in stores such as health foods stores (or on Amazon) for dyes with less PPD and fewer of the other ingredients listed above.







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