Contact allergy to Disperse Blue 106 and Disperse Blue 124 in German and Austrian patients, 1995 to 1999

Between 1995 and 1999, 1986 patients were tested in the 31 participating ce ntres of the Information Network of Departments of Dermatology (IVDK), all of them members of the German Contact Dermatitis Research Group, with a tex tile dyes series containing Disperse Blue (DB) 106 and 124, and since 1997 also with a mix of both. 86 patients (4.3%) reacted positively to DB 106 an d/or DB 124; with good concordance between the 2 allergens (Cohen's weighte d kappa 0.72), and the single allergens and the mix (kappa =0.75 in both ca ses), which had been tested in parallel in 969 and 975 patients, respective ly. In contrast, concordance between DB 106/124 and p-phenylenediamine and p-aminoazobenzene, respectively, was poor. Some 70% of positive reactions t o DB 106/124 had current clinical relevance. Furthermore, a significant inc rease in the proportion of DB 106/124-positive patients among those tested was found from 1995 to 1999. Hence, DB 106/124 are important allergens dese rving close monitoring. The use of a mix of DB 106 and DB 124 seems justifi ed in view of the close chemical similarity of both compounds. If possible, the presence of the allergen(s) in individual textiles considered causativ e should be checked by thin layer or column chromatography.