Tattoo pigment agglomerates measured in commercial ink stock products by computerised light microscopy

Lessons learned in a decade: Medical-toxicological view of tattooing

Tattooing has been part of the human culture for thousands of years, yet only in the past decades has it entered the mainstream of the society. With the rise in popularity, tattoos also gained attention among researchers, with the aim to better understand the health risks posed by their application. 'A medical-toxicological view of tattooing'-a work published in The Lancet almost a decade ago, resulted from the international collaboration of various experts in the field. Since then, much understanding has been achieved regarding adverse effects, treatment of complications, as well as their regulation for improving public health. Yet major knowledge gaps remain. This review article results from the Second International Conference on Tattoo Safety hosted by the German Federal Institute for Risk Assessment (BfR) and provides a glimpse from the medical-toxicological perspective, regulatory strategies and advances in the analysis of tattoo inks.

Tattoo pigment agglomerates measured in commercial ink stock products by computerised light microscopy

BACKGROUND

The incidence of clinical complications such as granuloma formation and sarcoidosis is often seen in black tattoos and may be associated with agglomeration of black pigment.

AIM

To measure count and dimensions of agglomerates in black tattoo inks vs red inks and to compare old inks and new inks of identical brands.

METHOD

Examination was performed by light microscopy (Olympus BX51^™ ) with magnification 40X, immersion oil. Photographs (Jenoptik Gryphax RGB camera) were taken of each ink sample and analysed by ImageJ software; count, area, width, height, circumference and circularity index were measured. Agglomerates were defined as width and height of objects above 800 nm. Twenty-one new unopened black inks and 17 new unopened red inks were compared. Furthermore, five old black inks and five old red inks, that had been opened and stocked for over 2 years, were compared with new products of the same brands.

RESULTS

Black agglomerates were area wise and with respect to width, height and circumference significantly larger compared with red agglomerates and more circularly shaped. Count of agglomerates was lower in black inks than in red inks, in accordance with bigger dimensions of black agglomerates. Comparison of old and new inks indicated old inks have larger agglomerates but variable bottle size and storage conditions may have confounded results.

CONCLUSION

Pigment agglomerates in black tattoo ink stock products were sized larger than agglomerates in red inks. Agglomerates found directly in black inks may predispose to granuloma formation in black tattoos causing sarcoid reaction.