Background: Finding alternative hair dyes for individuals allergic to para-phenylenediamine ... to PTDS who subsequently used a PTDS dye free of PPD tolerated these products.

Isabelle Lowe had dyed her hair several times in the past and never experienced a reaction, but that all changed when she used an at-home box dye.

The vast majority of reactions to hair-dye products are caused by PPD. [4–6] In past years, PPD was used in permanent hair dyes but not in semipermanent dyes. More recently, PPD has been used in ...