The potent sensitizer PPD is considered a key sensitizer in hair dye contact allergy. Modification of its molecular structure to 2-methoxymethyl-p-phenylenediamine (ME-PPD) reduces its skin sensitizing potency. We investigated the usage, behavior, and tolerance profile of ME-PPD-containing professional hair color products in a specifically tailored proactive market surveillance program in hairdresser salons across 5 countries. Hairdressers completed record cards for their clients, which were evaluated at the end of the program. 497 individuals received in total 2461 hair color treatments with ME-PPD-containing hair color. Feedback on compatibility was provided for 194 individuals: 6 individuals reported intolerance reactions, which were assessed as likely allergic contact dermatitis (2), likely irritation (2), or were unassessable (2); none of these reactions were severe or serious. Mild discomfort was reported by 46 individuals, while 142 individuals explicitly reported good tolerance to the ME-PPD-containing hair color. A total of 27 individuals applied ME-PPD-containing hair color more than 15 times (long-term tolerability). The study confirms good tolerability of ME-PPD-containing hair color. This is consistent with the primary prevention benefit of ME-PPD in terms of significantly reduced risk of skin sensitization induction and the reduced severity of elicitation reactions for all hair dye users.
Kock et al. (Tue,) studied this question.