Graying of the scalp hair is an inevitable physiologic process in human aging. It is caused by the loss of the pigmented-forming melanocytes from the hair follicles, which reflects loss of the melanocyte stem cell population in the aging hair follicles1,3,4
We surveyed clinical findings of gray hair. Forty to 49 years of age was the most frequent onset age of gray hair (194 out of 500 people). In the focal distribution of gray hair, the frontal area and temporal area revealed the high distribution. However, as this result was a personal report rather than the objective assessment, it suggests that the site of focal distribution that was visible to the subjects was the most commonly reported.
In current culture, the desire to look younger and the interest in beauty are widespread. Hair color has an important role in this. Many people do not want graying hair and they seek hair dyeing products to cover it. This is supported by our survey responses that most subjects said they dye their hair to look younger. Numerous hair dye products are being produced and sold according to such social needs. However, even though 68 types of commercially available hair dye products were arranged for them to choose in this survey, large number of the people who had experience with hair dye (233 out of 319 people, 73.0%) did not know which hair dye product they were using. Even if they experienced side effects due to hair dyeing, many people did not know exact brand name. The results reflect that many people did not have great interest about the type of hair dye used.
Hair dyeing products can cause various adverse effects, including allergic contact dermatitis5,6
. Additionally, an association with cancer and other systemic disease has also been suggested7-14
. Among the composition of hair dye, para-phenylenediamine, m-aminophenol, p-methylaminophenol and prophylenglycol are known as the primary substances15
that cause allergic contact dermatitis, but it is not easy to determine the other substances that cause side effects as many different types of products contain various additives such as henna or squid ink color16-21
. In most previous studies, the prevalence of the side effects due to hair dye has been obtained through patch testing with para-phenylenediamine. However, the prevalence of positive patch test result is not equivalent to prevalence of hair dye allergy22
. The prevalence of the side effects from hair dye has not been established in Korean people. In this study, the prevalence of the side effects due to hair dye is 23.8% (76 out of 319 people). The result that 47.2% (26 out of 55) people experienced side effects even after they changed the product suggests that the mild symptoms induced by hair dyeing, such as a tingling sensation of the eye and pruritus, may be under-recognized. Despite the experience of side effects, most (68 of 76 people, 89.5%) continue hair dyeing. Furthermore, a small portion of the subjects (20 out of 76 people) who experienced side effects visited the hospital for treatment. People do not realize typically the seriousness of the side effects or the need for treatment. Also, even if the patients recognize the side effects, they considering them normal symptoms that can appear with dyeing rather than recognizing them as adverse effects, and these are results in the people continuing to dye their hair because there are no other alternatives.
In this study, many people did not know the exact brand name of the hair dye product that they were using, and continued hair dyeing in spite of side effects. Also, a large portion of the people who experienced side effects of hair dyeing did not receive any treatment. The results suggest that most of the people who had experienced hair dyeing have insufficient knowledge of hair dye products. This study was conducted to determine the public's perception on hair dye products and the side effects, and as a result, it was confirmed that the level of awareness was fairly low.
Therefore, it is necessary for people to fully know the ingredients of hair coloring products and to properly use them, such as conducting a patch test for the causative agents of contact dermatitis before use, in order to decrease the side effect caused by hair coloring products. Directions and included literature of hair dye products must be improved to inform people about the ingredients, the side effects and patch test method. It is advisable to introduce a system that will enables users to become aware of the ingredients of hair coloring products and the side effects of hair coloring products. We should give broad opportunities for users to become aware of the side effects of hair coloring through education, publicity and publication of an informational booklet so that people can appropriately use hair coloring products. Additionally, for the people who experience side effects of hair dye products, a patch test for the main substances that cause contact dermatitis may be helpful to select hair dye products and to decrease the side effects of them.