Patch testing with textile dye mix in Italy: A 2-year multicenter SIDAPA study

Disperse dyes (DDs), mostly represented by azo dyes, are small and lipophilic molecules characterized by low cost and simple application on clothing. If the textile fastness is poor, DDs are easily released onto the skin causing allergic contact dermatitis (ACD). DDs are still common sensitizers despite their reduced use for the coloring of synthetic fibers (polyester, acetate, nylon, or their blend with other fiber types).1 From the 1990s, several DD mixes of different compositions and concentration were used to save space and time, and in 2015 the ESCD included in the baseline patch test series a textile dye mix (TDM) 6.6% containing eight DDs.2 In fact, a large number of dyes are available and patch testing with extracts of the garment per se is not always possible. Moreover, there was a need for a marker because p-phenylenediamine (PPD) was not considered sufficient. In Europe the prevalence of TDM 6.6% positivity ranges between 2.1% and 6.9% with a clinical relevance in 31% of cases,3 whereas a representative study on the Italian trend is lacking. In this study, the prevalence of positivity to TDM 6.6% in a large Italian population sample was analyzed.