Survey of Chemical Substances in Consumer Products, 61 – Colorants in transferable picture tattoos for the skin

Colorants in transferable picture tattoos for the skin

6 Discussion

Transferable picture tattoos for children (and adults) are used for the decoration of the body, and therefore, they should comply with the Cosmetic Directive. Picture tattoos can be purchased in special shops, and they may also be attached to weekly/monthly magazines, food sold in kiosks and also in supermarkets, during some special campaigns.

The chemical analysis of 36 picture tattoos stickers, bought in Denmark, revealed that only a limited number of colorants were used in the formulation of these products. Thus, only 11 of the 129 organic colorants investigated in the present study were identified in the picture tattoos. All of the identified colorants are permitted for the use according to the Cosmetic Directive. The blue colour in several samples could not be identified. Thus, green and violet colours, which may be composed of blue together with yellow and red respectively, in several samples, could also not be identified. A dark blue/black residue, found after extraction of these samples in HPLC-solvent and THF, may indicate that the blue colour was bound with the matrix (synthetic polymers), and therefore, it was insoluble in the solvents. Another possibility is that the unidentified blue colour is Pigment Blue 29 (CI 77007), which is permitted for the use in cosmetic products. This colorant (Na₂Al₆Si₆O₂₄S₂), which is also used for the composition of green, violet and pink pigments, is insoluble in water and organic solvents; and therefore, it is often used in the formulation of decorative cosmetics (12).

The black colour could not be identified in three picture tattoos, which was composed of only this colour (visible). As p-phenylenediamine (PPD) is used as colouring agent in black temporary tattoos and hairs dyes, one of the products (4-02519) was investigated for the content of PPD employing a previously described method (3). PPD was not detected in the sample, at a detection limit of 2 ppm.

The content of the colorants was labelled only in one of the investigated products. However, The declared colorants (CI 15985, CI 19140 and CI 42090) in this sample, could not be identified. It is possible that the contents of these colorants in the investigated sample may be below the detection limit (0.5 ppm), or the colorants were bound with the acryl resin (matrix), which is not soluble in the solvents used for the extraction.

A semi-quantitative determination of the 11 identified colorants in the picture tattoos revealed that the content of 7 of the colorants in the samples was 35 ppm (maximum 4479 ppm). Risk assessment of these seven colorants, with regard to their allergenic potential has been performed in the present study. The content of remaining identified colorants in the picture tattoos was maximum 12 ppm.

Among the seven colorants, CI 15850 and CI 75300 have been shown to cause allergic reaction in a few cases, but never in association with the use of picture tattoos. Furthermore, negative results were obtained when the sensitisation potential of CI 15850 and CI 45100 was tested in animal experiments according to OECD guidelines. However, CI 15850 was found to be a skin sensitiser in a test, which was performed using a non-validated method. The reliability of the results of this test is uncertain due to use of a non-validated method. Two of these seven colorants, i.e. CI 11920 and CI 45100 are also used as hair-dye ingredients, and in this respect, they have also been analysed by QSAR (based of their physical-chemical properties) to determine whether these can induce allergic reactions in humans. The chemical structure of CI 11920 indicates that it may be a moderate to strong allergen. However, further studies are required to confirm the sensitisation potential of this colorant. In the scientific literature, there is no information on allergic reactions in humans from the use of CI 11920. CI 45100 has been classified as a weak allergen on the basis of physical chemical characteristics, and it produced negative results in animal tests for the sensitisation potential employing a validated official method.

The literature survey did not reveal any information concerning allergenic potential of the colorants CI 45220, CI 13015, CI 15525, neither in animal tests nor in humans. These colorants might have been investigated, but the results are not published. Similarly, there may be cases of allergy by the use of these substances, but not reported. A proper risk assessment is always limited to the published reports that are available in the scientific literature. There are published reports of allergic reactions to a number of colorants (6, 7), which are permitted for the use in cosmetic products (Annex IV of the Cosmetic Directive), but none of were found to be present in the investigated picture tattoos. The sparse information on the colorants identified in the present investigation should, therefore, not be considered as the allergenic potential of the colorants, in general, is not investigated.

On the basis of the present investigation, it is concluded that the potential risk of allergic reactions from the identified colorants in transferable picture tattoos is limited. .

The Danish EPA has received a few complaints about children getting skin reactions from the use of picture tattoos. The reason for these skin reactions from picture tattoos is not known. No cases of allergic skin reaction from transferable picture tattoos have been reported in the scientific literature, from selected Dermatology Departments, or from the Danish Consumer Association.

Taking into account the contents of colorants in picture tattoos as well as the risk assessment as described above, allergy problem from the use of picture tattoos seems to be limited.

All identified colorants in the investigated picture tattoos are permitted for the use in cosmetic products. However, the colorants CI 45100 and CI 45220 should only be used in products, which come in contact with the skin for a short period. In most of the investigated products the content of colorants was not declared.