Identification of causative chemicals of allergic contact dermatitis using a combination of patch testing in patients and chemical analysis. Application to cases from industrial rubber products.

3 cases of allergic contact dermatitis from industrial rubber products were investigated using a combination of patch testing in patients and chemical analysis of causative rubber products by gas chromatography (GC), GC-mass spectrometry (GC-MS) and high-performance liquid chromatography (HPLC). Our studies revealed N-isopropyl-N'-phenyl-p-phenylenediamine (IPPD), a typical rubber allergen, as a causative chemical in a case from a brand of heavy-duty rubber gloves and a case from a black rubber ring for car manufacture, and zinc ethylphenyldithiocarbamate (ZEPC), a dithiocarbamate (DTC)-type accelerator, as a causative chemical in a case from a brand of rubber work gloves: both IPPD and ZEPC, which showed positive patch test reactions, were confirmed in the extracts of the causative rubber products by GC, GC-MS and/or HPLC.