Two decades of p‐phenylenediamine and toluene‐2,5‐diamine patch testing – focus on co‐sensitizations in the European baseline series and cross‐reactions with chemically related substances

Abstract

Cross-reactivity was commonly found among individuals sensitized to PPD or TDA, and was strongly related to the strength of the patch test reaction. Regarding co-sensitizations, a frequently appearing or common exposure source could not be determined. However, modification of the allergen by, for example, the skin microbiota may have caused the formation of molecules that are, for the human immune system, indistinguishable from PPD.

Factors associated with p‐phenylenediamine sensitization: data from the Information Network of Departments of Dermatology, 2008–2013

“…In several reports, increased concomitant reactivity to chemically unrelated baseline series allergens (e.g. metals and essential oils) were noted in PPD‐sensitized patients . However, we did not find any particular association with the risk factors of PPD sensitization that we had used (data not shown in detail).…”

Eyebrow allergic contact dermatitis caused by m‐aminophenol and toluene‐2,5‐diamine secondary to a temporary black henna tattoo

“…In our patient, the first manifestation of sensitization to PPD and its derivative occurred after the use of eyebrow dyes containing m ‐aminophenol and TDA. The latter is less sensitizing than PPD, and so is commonly used as an alternative for hair dyes in PPD‐sensitized patients . Nevertheless, a cross‐reaction between TDA and PPD has been described, in particular in patients strongly sensitized to PPD (as usually occurs after temporary henna tattoos); therefore, patients who are allergic to PPD should also avoid products containing TDA.…”

Evaluation of in vitro testing strategies for hazard assessment of the skin sensitization potential of “real‐life” mixtures: The case of henna‐based hair‐colouring products containing p‐phenylenediamine

“…These cosmetics may contain combinations of >100 different substances, for example, dyes, couplers, and fragrances; therefore, they are complex mixtures of a wide range of synthetic compounds, many of them with potential skin sensitization properties . Among these chemicals, the aromatic amine p ‐phenylenediamine (PPD) is a cost‐effective hair dye that is widely used, specifically in semipermanent and permanent products; however, it is frequently associated with contact sensitivity reactions in humans after the use of hair colourants . Furthermore, PPD cross‐reacts with chemically related molecules, for example, those used in cosmetics.…”

“…12,16,17 Among these chemicals, the aromatic amine p-phenylenediamine (PPD) is a cost-effective hair dye that is widely used, specifically in semipermanent and permanent products; however, it is frequently associated with contact sensitivity reactions in humans after the use of hair colourants. 11,[17][18][19][20] Furthermore, PPD cross-reacts with chemically related molecules, 20 for example, those used in cosmetics.…”

“…Therefore, LAW low levels exposure ensures safe use of henna as a hair dye 25. T A B L E 4 Results of CD86 expression assessment of hair dye ingredients with the peripheral blood monocyte-derived dendritic cell (PBMDC) test CV 80 , concentration that promotes cell viability of ≥80%; DMSO, dimethylsulfoxide; EC20 , concentration at which the test material induces a ΔCD86 of 20%; ND, not detected; NS, non-sensitizer; S, sensitizer.…”