Determination of Rosin Oxidation Products in Pigments and Inks as a Potential Source of Tattoo Allergenicity.

BACKGROUND

The vast majority of allergic tattoo reactions involve red-shaded tattoos without a causal explanation.

OBJECTIVE

To determine rosin oxidation products (ROPs) in pigments and tattoo inks as a hypothesised source of tattoo allergenicity.

MATERIALS AND

METHODS

Content of pigment samples (n = 112) and tattoo inks (n = 119) was analysed using newly developed UHPLC/PDA/MS methods, XRD and high-resolution MS.

RESULTS

ROPs were found at varying levels in 32 pigments and 38 tattoo inks. The mean ROP level of red inks was approximately three-fold higher than that of non-red-spectrum inks. Among 24 red-spectrum inks with ROPs, azo pigments PR170, PR266, PR22, PY74 and quinacridones PR122 and PV19 were frequently identified. PR170 was present in 21 of those inks.

CONCLUSIONS

To explain results, a manufacturing model was developed showing rosination pathways, with only some having likely allergenic outcomes. Inks whose pigments were produced with rosin incorporated and/or irreversibly bound are the most likely to be allergenic. ROPs within those inks are believed to remain in the body after tattooing, acting as haptens. This view is consistent with biopsy reports of allergic reactions to red-shaded tattoos. We propose that ROPs may be at least partially responsible for those reactions. Pending proof of this proposal, tattoo-ink manufacturers might choose to avoid rosinated pigments.