Sensitization to disperse dyes in a patch test population over a five-year period.

Background: In spite of sporadic data pointing at the role of textile dyes as important contact allergens, only few studies have addressed the issue of the frequency of sensitization to textile dyes in populations of consecutive patients.

Objective: The purpose of this study was to evaluate the prevalence of sensitization to disperse dyes, to investigate cross reactivity between azo dyes and para-amino compounds, to describe azo-dye-positive patients, and to study the correlation between clinical aspects and sensitization to different disperse dyes.

Methods: From January 1996 to December 2000, 6,478 consecutive patients were tested with 7 textile dyes: Disperse Blue 124, Disperse Blue 106, Disperse Red 1, Disperse Yellow 3, Disperse Orange 3 (DO3), para-aminoazobenzene (PAAB), and para-dimethylaminoazobenzene (PDAAB).

Results: Of the above, 437 patients were allergic. The most common sensitizers were Disperse Blue (DB) dyes and Disperse Orange 3. Both the clinical aspect and the localization of the lesions were unusual in a fair percentage of cases, especially in DB-positive subjects. Involvement of skin folds was observed in 27% of disperse dye-positive patients, mainly comprising DB-sensitive women. Cross-reactivity between azo-dyes and paraphenylenediamine (PPD) was frequent in DO3-, PAAB-, and PDAAB-positive subjects, but not in DB-allergic ones. Moreover, cross reactions between DB106 and DB124 were observed in 59% of DB106- and/or DB124-positive patients.

Conclusions: The frequency of disperse dye allergy is higher than generally estimated. Further studies, using routine diagnostic testing with disperse dyes, are needed to investigate whether this increasing trend is present outside of Europe.