Figure 2.

Main organic pigments in red tattoo allergy biopsies and their sensitizing decomposition products. (A) In the majority of biopsies the red pigments found are the naphthol AS azo pigments. The diazo P.O. 13 (B) and dioxazine P.V. 23 (C) pigments were found in 8% and 11% of all biopsies, respectively. (A‐C) Structural features determining the chemical group are marked in bold. (D) Known decomposition products of these pigments that are classified as sensitizers by manufacturers or the CLH system are listed with literature references and CAS number. CAS, chemical registry number; CLH, harmonized classification and labeling; P.O., Pigment Orange; P.R., Pigment Red; P.V., Pigment Violet