Acetylator phenotype in patients with p-phenylenediamine allergy.

p-Phenylenediamine (PPD) has been widely distributed as hair dye ingredient and may be responsible for contact dermatitis. Since not all the subjects exposed to PPD react to the substance, we tested a possible predisposing factor of cutaneous drug metabolism. Eighty-five patients were selected on the basis of their patch test result for PPD. The acetylator status of patients was estimated using HPLC analysis of urinary caffeine metabolites. Among patients with a negative result for PPD, there were three groups, i.e. fast, intermediate and slow acetylators, just as in the healthy population. However, we could not find any rapid acetylator in the PPD-sensitive patient group, and slow acetylators were more often encountered in this group (p < 0.05). The acetylator phenotype might be a good marker for the cutaneous sensitivity to PPD.