A Consumer Council survey has found important information missing on the labels of many hair dye products in the market.
In a sample size of 30 different hair dyes, the Council has found about 18 samples to fall short of the labelling requirements under the Pharmacy and Poisons Ordinance.
In particular, the Council is concerned about the presence of a chemical substance, para-phenylenediamine (PPD), used widely as a permanent hair dye ingredient.
Some did not specify its quantity (usually in percentage by weight).
Nor the required caution statement in both Chinese and English: "Caution. This preparation may cause serious inflammation of the skin in certain persons and should be used only in accordance with expert advice."「注意：此藥可使某些人士皮膚嚴重發炎，須照專家指示使用。」
Although some of the samples contained similar caution statement, the law requires that it must be in the exact wording in both languages as above.
Under the Ordinance, hair dyes containing phenylenediamines, toluenediamines or other alkylated-benzene diamines or their salts are subject to these labelling requirements.
The Consumer Council has referred all the samples to the Department of Health for further assessment and follow-up action deemed necessary.
According to the European Commission's Scientific Committee on Consumer Products (SCCP), the chemical PPD is classified as "extreme" sensitizer to the skin.
Of the 46 hair dye substances assessed by the SCCP, 27 met the criteria for classification as skin sensitizer with 10 of them considered "extreme", 13 "strong" and 4 "moderate".
Further, a study in the British Medical Journal in 2007 has revealed that allergic reactions to hair dyes are increasing as more and younger people dye their hair. Other studies showed that contact allergy to PPD has increased in the general population.
Hair dyes, especially permanent hair dyes, do contain some skin sensitizers which might have the potential to cause allergic reactions such as reddening of the skin, inflammation and itchiness to the users.
Users are therefore advised to minimize direct skin contact with the dyes. Those with skin problems, especially women during the first three months of pregnancy or while breast-feeding, are also advised to avoid using permanent hair dyes.
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