Ms. Xu, 46, has always had the habit of dyeing her hair, especially when she is older, white hair tends to grow out, so the number of blackenings has also begun to increase, sometimes twice a month.
Last week, Ms. Xu went to the barber shop as usual to dye her hair, and the barber recommended and used a hair dye that was said to be "natural and non-toxic side effects". However, less than two hours after dying her hair, Ms. Xu began to have dizziness, headaches, nausea and fatigue, and after two or three days, she did not see any improvement, so she had to go to the hospital for examination.
After listening to the doctor's advice, in order to find the cause of the disease, Ms. Xu bought the hair dye she used before and took it to the hospital for consultation. After carefully reading the ingredient list, the doctor found that the hair dye contained an excess of "p-phenylenediamine", and p-phenylenediamine is a strong allergen, which is easy to cause a variety of discomforts such as dermatitis, and has a certain carcinogenicity, and Ms. Xu's discomfort may be caused by it.
I. Hidden cancer "accomplices" in hair dyes
Approaching the New Year, changing hair color has become a way for people to "make a makeover". Hair dye as a special product that can change the hair color, the composition of the hair dye can be no less - phenylenediamine, p-aminophenol, toluenediamine, resorcinol, chloride resorcinol, etc., of which p-phenylenediamine, p-aminophenol is the most commonly used hair dye dye active ingredient, but also an important element that allows hair color to be maintained for a long time.
Although p-phenylenediamine has a fixative effect, it is also likely to pose a "threat" to human health. P-Phenylenediamine is a simple aromatic diamine. As an intermediate, it can bind to hydrogen peroxide or with ferric chloride, changing color. It has a strong affinity for keratin in hair, and its oxidation process is the fixation process of color when dyeing hair.
So why call it a "lurking killer"?
1. P-phenylenediamine is irritating. P-phenylenediamine is not colorless and odorless, and during the hair coloring process, the substance can irritate the mucous membranes of the skin or respiratory tract, causing discomfort in the human body.
2. P-phenylenediamine may be sensitized. There was a case of hair dye production workers who were exposed to high-dose p-phenylenediamine by mistake, resulting in acute poisoning, when the patient's blood methane was as high as 78%;
3. P-phenylenediamine is carcinogenic. It forms a highly nucleophilic oxidation product in the body, which can act directly on DNA, increasing the probability of cell cancer.
At present, the "Cosmetic Hygiene Code" implemented in China has included p-phenylenediamine in the restricted substances, stipulating that its maximum limit ratio is 6%. Although the possibility of health threats is reduced at a safe dose, due to the different physiques of individuals, it is necessary to learn to protect themselves during use. In particular, people who often dye their white hair black.
Second, the doctor reminds: white hair dyed black is more dangerous
Li Xinquan, director of the Department of Hematology of the Beijing Armed Police General Hospital, said that black hair dyes contain the most phenylenediamines and heavy metal salts, and white hair is dyed black or more dangerous. During the staining process, phenylenediamines are heated, contact with the scalp into the capillaries, and reach the bone marrow with blood circulation, which may cause leukemia if it acts repeatedly on hematopoietic stem cells for a long time. White hair dyeing is common in middle-aged and elderly people with more white hair, and some people even need to dye black on a large area. In the face of health risks, middle-aged and elderly people should not dye their hair too frequently.
For netizens concerned about "whether pure natural plant hair dye can reduce the damage to the scalp". Experts from the Institute of Chemistry of Zhejiang University said that the so-called pure natural hair dyes are mostly "gimmicks", and in terms of efficacy, the active ingredients of plant hair dyes are lower; the price is much higher than that of chemical synthetic hair dyes. The so-called pure natural, and no guarantee, are mostly "hanging sheep's heads to sell dog meat".
Is it true that hair coloring causes cancer?
"Hair dyes cause cancer" is one of the most concerned topics, and the largest prospective study on the topic of "individual use of permanent hair dyes versus the risk of cancer and specific cancers" gives us some reference answers.
Published in the British Medical Journal (BMJ), the study, jointly organized by the Team at Brigham and Women's Hospital at Harvard Medical School and the Dana-Farber Institute for Cancer Research, covered 117,000 women aged 30-55 years and was followed up for up to 36 years, during which 20,805 solid carcinomas, 1,807 hematologic cancers, 22,560 basal cell carcinomas and 2,792 cases of squamous cell carcinoma of the skin occurred.
After adjusting for other influencing factors, the researchers found that women who used permanent hair dyes had no increased risk of most cancers,including solid cancers such as bladder, brain, colorectal, kidney, lung, and blood, immune system, and most skin cancers;and there was no significant association in cancer-related deaths.
However, the use of permanent hair dyes has been significantly associated with some breast cancers (estrogen receptor negative, progesterone receptor negative) and the risk of ovarian cancer, and the risk of cancer increases with the increase in the number of uses.
Although the results of the study showed that permanent hair dyes may play an inducing role in some cancers, the study was an observational study, and the causal relationship between hair dyes and cancer risk could not be established, and the study still had certain limitations.
Compared with the risk of cancer, adverse consequences such as allergies and poisoning caused by hair coloring are more common and need the attention of the target population. If you want to dye your hair safely, you must keep in mind the choice of products and the precautions in the hair coloring process.
Fourth, if you want to dye your hair safely, remember 5 points
1. Correctly choose hair dye
Beauty salon market "fish eye mixed beads", consumers must carefully check the packaging box before purchasing, check whether there is a production batch number, obtain the Approval Document number of special-purpose cosmetics of the Ministry of Health of the People's Republic of China, and its batch number should be the word 00 ×× of the Special Character (200 ×); its safety has been reviewed by the Ministry of Health, and has a health license batch number; try to choose a well-known brand, and the large factory generally has relatively strict quality control.
2. Use up to twice a year
Ma Jing, deputy director of the Department of Dermatology and Venereology of the Second People's Hospital of Guangdong Province, said that the hair dye has a strong sensitizing effect on phenylenediamine, and it is recommended that hair dyeing not be too frequent, it is recommended to use it up to 1-2 times a year, and only need to dye newly grown hair for the second time. The interval between two consecutive hair tints is preferably more than half a year.
3, before dyeing should do "skin test"
In order to prevent strong allergic reactions, it is best to do a skin test before hair coloring. The specific operation is to apply a little hair dye behind the ear and observe whether there are allergic manifestations such as redness and blistering for 2 to 3 days.
4. Do a good job of protection when dyeing
In addition to checking whether the skin on the head, face and other parts that are easy to contact the hair color product is damaged before use, pay attention to wearing ear tips and gloves to avoid direct contact with the skin. If it occurs into the eye, rinse immediately with water.
5. Do not dye hair for contraindicated people
Due to the strong sensitization of hair dyes, it is contraindicated for 6 categories of people such as blood system diseases and allergic patients, people with inflammation and wounds on the scalp, the elderly with low immunity, young children, pregnant women and women who are still breastfeeding, and it is best not to dye hair easily.
Hair coloring does not mean that it will necessarily cause the occurrence of cancer, but from a health point of view, or should reduce the number of use of hair dye, for allergies, pregnant women, and breastfeeding women, want to change hair color, if you really pay attention to the value, it is recommended to buy a wig to wear, it will be safer than hair coloring.
Resources:
[1] Does hair coloring increase the risk of cancer? Harvard Study: Most Don't, But The Risk of These Cancers Increases" e-Drug Global 2020-09-11
[2] "It is best not to wash your hair before dyeing your hair, and be careful to wash away the "protective film" of the scalp". People's Daily News.2019-04-01
[3] "Hair coloring causes cancer"? Studies say black hair dyes are the most dangerous". Life Times.2014-10-29
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