CROSS-SENSITIZATIONS BETWEEN AZO DYES AND PARA-AMINO COMPOUND - A STUDY OF 236 AZO-DYE-SENSITIVE SUBJECTS

Combined sensitizations to different azo dyes, probably based both on true cross-sensitization and on simultaneous positive reactions, have frequently been described. However, since azo dyes are included in the standard series in a minority of countries, the case studies consider ed comprise, with few exceptions, a small number of subjects. The aim of our study was to investigate cross-reactions between different azo dyes and para-amino compounds in ate-dye-sensitive subjects, to study the clinical aspects of azo dye dermatitis, to assess the relevance of sensitization to azo dyes, and to relate the pattern of cross-sensiti zations to the chemical structure of the different dyes. Out of 6203 c onsecutively tested patients, 236 were sensitized to at least 1 of 6 a zo compounds employed as textile dyes, included in our standard series . 107 subjects reacted to Disperse Orange 3 (DO3), 104 to Disperse Blu e 124 (DB124): 76 to p-aminoazobenzene (PAB), 67 to Disperse Red 1 (DR 1), 42 to Disperse Yellow 3 (DY3), and 31 to p-dimethylaminoazobenzene (PDAAB). Go-sensitizations to para-phenylenediamine were present in m ost subjects sensitized to DO3 (66%) and PAAB (75%), in 27% and 36% of DR1 and DY3-sensitive subjects, and only in 16% of subjects sensititz ed to DB124. Apart from the hands and the face, the neck and the axill ae were the most frequently involved skin sites. Whereas the involveme nt of flexural areas was mainly connected with sensitization to DB124, in patients with hand dermatitis and in those working as hairdressers , sensitization to DO3 and PAAB was more frequent. Moreover, in the fo rmer patient group, a history of textile dye allergy was most frequent ly obtained. Out of 33 patients tested with an additional textile dye series, only 5 subjects reacted to anthraquinone dyes. Cross-sensitiza tions between azo dyes and para-amino compounds can partially be expla ined on the basis of structural affinities.