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Penetration and haptenation of p ‐phenylenediamine
Author(s) -
Pot Laura M.,
Scheitza Simone M.,
Coenraads PieterJan,
Blömeke Brunhilde
Publication year - 2013
Publication title -
contact dermatitis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.524
H-Index - 96
eISSN - 1600-0536
pISSN - 0105-1873
DOI - 10.1111/cod.12032
Subject(s) - p phenylenediamine , sensitization , acetylation , chemistry , penetration (warfare) , enzyme , hair dyes , allergen , adduct , diacetyl , allergy , biochemistry , immunology , medicine , organic chemistry , dyeing , operations research , engineering , gene
Although p ‐phenylenediamine (PPD) has been recognized as an extreme sensitizer for many years, the exact mechanism of sensitization has not been elucidated yet. Penetration and the ability to bind to proteins are the first two hurdles that an allergen has to overcome to be able to sensitize. This review is an overview of studies regarding PPD penetration through skin (analogues) and studies on the amino acids that are targeted by PPD. To complete this review, the auto‐oxidation and N ‐acetylation steps involved in PPD metabolism are described. In summary, under normal hair dyeing exposure conditions, <1% of the applied PPD dose penetrates the skin. The majority (>80%) of PPD that penetrates will be converted into the detoxification products monoacetyl‐PPD and diacetyl‐PPD by the N ‐acetyltransferase enzymes. The small amount of PPD that does not become N ‐acetylated is susceptible to auto‐oxidation reactions, yielding protein‐reactive PPD derivatives. These derivatives may bind to specific amino acids, and some of the formed adducts might be the complexes responsible for sensitization. However, true in vivo evidence is lacking, and further research to unravel the definite mechanism of sensitization is needed.