Results: Of 28 PPD-allergic patients seen since October 2006, 16 (57.1%) tested negative to all other substances on the dye series. Eleven tested positive to PTDS; of these, several were also ...

[4–6] In past years, PPD was used in permanent hair ... In our study, only 1 of 27 individuals who tested negative for allergy to PTDS had positive reactions to any of the other substances ...