On Hypersensitive to “Para Group”

Abstract

Allergy to paraphenylenediamine (PPD) has been known for some time because of the extensive use of this substance in the dye industry. On the basis of our observation of 918 patients we could demonstrate 3.0 % PPD hypersensitivity with the patch test method. The real importance however of PPD allergy is that we may give data to elucidate the connection between chemical structure and sensitization. It is not necessary to emphasize the theoretical and practical importance of that task, since it would offer a real basis for that difficult and important pathological problem only partially evaluated as yet. Landsteitier was the first to prove in his animal experiments that certain labile chemical groups, chains, the so-called determinants, acquire a decisive role in sensitization. The exact meaning of what we call determinant is open to discussion. It includes not only simple chemical groups as acid group or aliphatic side chain, but also positional and dimensional isomery and even isostery symbolising physiochemical resemblance (i).The fact that compounds of para-, nieta-, ortho-position proved to be different from the point of view of sensitization is a good example of positional isomery ("Stellungsisomerie"). This is extremely well demonstrated in Landsteiner's precipitation animal experiments made with p-m-o-aminobenzenesulfonic acid (2).