Sensitization paraphenylenediamine

To 10 c.c. of the milk arc added 15 c.c. of raw milk known to be genuine and 3 drops of aqueous 2% paraphenylenediamine solution (freshly prepared) a blue colour appears in presence of hydrogen peroxide. This reaction is highly sensitive. 

Hair dyes (for example henna, paraphenylenediamine, and paratoluenediamine) have been reviewed (1). They have moderate to low acute toxicity. Poisoning is rare and occurs only after oral ingestion. Contact sensitization usually occurs from unprotected professional exposure, but the prevalence has stabilized or fallen over the years. In vitro genotoxicity tests of hair dye ingredients have often been positive, but the relation to in vivo... 

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. 

The occurrence of photoallergy to esters of / -aminobenzoic acid was described in the discussion of photoallergic topical drugs (Sect. P.IX). Ordinary contact sensitization is more frequent, described as early as 1949 by Meltzer and Baer (1949). Cross-reactions to other para compounds such as paraphenylenediamine-de-rived hair dyes, azo and aniline dyes, local anesthetics (procaine, benzocaine), sulfonamides, and / -aminosalicylic acid occur. The spectrum of cross-reactions varies from patient to patient (Fisher et al. 1958). Fisher (1977) has emphasized the importance of recognizing impurities in a compound as responsible for certain crossreactions, i.e., benzocaine in glyceryl-/7-aminobenzoic acid (Escalol 106),... 

Mayer and Sulzberger (1931) using Ursol (paraphenylenediamine) and Salvarsan showed that in winter 75% of the animals are strongly sensitized, whereas in summer only 12% are sensitized. 

This eczema is the consequence of a sensitization by paraphenylenediamine or one of its derivatives. It is not, however, frequent when one thinks of the number of people who have their hair dyed ... 

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. 

In order to estimate the sensitization, we applied 10% paraphenylenediamine in vaseline on the shaved flank but without the jacket . We did not observe, after 12—24 hours, any redness or infiltration in the 12 sensitized guinea pigs (N. Hun-ziKER and coll., 1964). 

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. 

Fig. 22. Guinea pig sensitized to paraphenylenediamine. Nipple 14 hours after a single application of 10% paraphenylenediamine in vaseline spongiosis. Macroscopic examination...

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 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. 

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. 

Allergic reactions to henna solutions are more usually due to paraphenylenediamine, which is added to henna to obtain a dark, blackish color and is a frequent contact sensitizer [29, 30, 31, 32 ]. 

Paraphenylenediamine (PPD) is a colorless compound oxidized by hydrogen peroxide in the presence of ammonia. It is then polymerized by a coupling agent to produce a color. Although a well-known allergen in hair dyes, PPD can be found as a cause of contact dermatitis in chin stains or in milk testers. It is also a marker for group sensitivity to para amino compounds such as benzocaine, para-aminobenzoic acid, azo-dyes and some sulphonamides. 

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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