Paraphenylenediamine sensitization with

We wanted to cite the experiments of those who have shown that it is possible to obtain a sensitization with paraphenylenediamine, whereas, our results were negative with one exception. This exception shows that the macroscopic examination is not sufficient to ascertain a failure of sensitization. 

There is a risk of sensitization from paraphenylenediamine when it is applied to the skin in combination with henna (4—6). This can result in contact allergic reactions as well as persistent contact leukoderma, as illustrated in five patients with paint-on henna tattoos (7). AH were positive on patch-testing with paraphenylenediamine. One developed erythema multiforme 4 weeks after the last application and the authors found no other causes of erythema multiforme. 

In 1931, Mayer sensitized the flank of guinea pigs by applications of 10% paraphenylenediamine in vaseline. Usually 4 weeks after the beginning of sensitization he performs a patch test on the untreated flank with 10% paraphenylenediamine in vaseline (under some sort of jacket) ( Festschlie6ende Jackchen ). The tests were distinctly positive after 12 and 24 hours on the guinea pigs whose sensitization was successful. 

We sensitized 12 guinea pigs on the neck with 11 applications (within 12 days) of 20% paraphenylenediamine in vaseline. 

Mayer and Sulzberger (1931) write that it is easier to sensitize guinea pigs with paraphenylenediamine when they take their winter food. In our animals, sensitization was carried out during winter and in spite of that, they were not sensitized. 

In 1951 and 1954, Duesberg sensitized guinea pigs with paraphenylenediamine (10% in vaseline) by 8 daily applications and tested the animals on the 20th day after the beginning of sensitization, by an intradermal injection of a 2% aqueous solution. 

We should like to insist again that, in guinea pigs which have received a sensitization treatment with paraphenylenediamine, all the patch tests were negative under macroscopic examination. However, in one case we observed well developed spongiosis on the nipple. Macher and Sennlaub (1963) have confirmed this observation with DNCB. This again demonstrates that microscopic examination affords more information than macroscopic examination. 

In a literature review of the epidemiology of PPD sensitization as determined by patch tests, the median prevalence among dermatitis patients was 4.3 % (Asia), 4 % (Europe), and 6.2 % (North America) [361]. A multicenter European comparative PPD sensitization study found that such sensitization occurred more frequently in Central and Southern Europe than in Scandinavian countries [362]. Occupational exposures account for only a small portion of PPD allergy cases [363, 364], and the predominant cause of PPD allergy is due to consumer exposure to hair dyes [365-367]. Some cases of PPD sensitization may be due to cross-reaction with benzocaine, A-isopropyl-A-phenyl-paraphenylenediamine, p-toluenediamine, and sulfonamides [361-363, 368, 369]. In PPD-sensitized individuals, clinically severe allergic reactions may occur with cosmetic hair dyeing [361]. 

The demand for white and coloured mbber articles for various applications is steadily growing. Rubbers are, depending on their content of olefinic double bonds, very sensitive to ozone, and hence effective antiozonants are necessary. Due to their discolouring and staining effect, para-phenylenediamine antiozonants cannot be used in compounds for white or coloured articles. A survey of the effectiveness of Vulkazon AFS, a cyclic acetal providing excellent ozone protection in coloured compounds based on various elastomers, is presented. The effectiveness of the cyclic acetal is compared with paraphenylenediamine antiozonants in chloroprene, butyl and halobutyl compounds. The effect in diene rubbers, where the cyclic acetal has to be used in combination with waxes, is investigated. Cyclic acetals do not affect the peroxide cure like other antiozonants and hence the material has also been tested in peroxide-cured cable jacket compounds based on a saturated elastomer. 2 refs. 

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