While people have tattooed their bodies for thousands of years, it’s only recently that scientists have come to understand what exactly happens to the body as it’s turned into art — including when the process of tattooing doesn’t go exactly as planned. It’s estimated that 10 percent of people suffer an adverse reaction when they’re tattooed, and a study released Tuesday takes a step towards explaining why.
A team of Europe-based scientists report in Particle and Fibre Toxicology that allergic reactions to tattoos could be linked to metal particles from tattooing needles. Previously it was thought that most tattoo allergies emerge because individuals are allergic to specific ink colors, with red being the most frequent offender.
However, in this study scientists found that chromium and nickel particles could be entering into an individual’s lymph nodes as a result of needles that have suffered abrasions. Tattoo needles are typically 6 to 8 percent nickel and 15 to 20 percent chromium.
“There is more to tattoos than meet the eye,” co-author Hiram Castillo Ph.D., a scientist at the European Synchrotron Radiation Facility (ESRF), explains. “It is not only about the cleanliness of the parlor, the sterilization of the equipment or even about the pigments. Now we find that the needle wear also has an impact in your body.”
This study was a followup to previous research conducted by the same team, which explored whether or not there were traces of iron, chromium, and nickel in ink pigments. When that link wasn’t established, they turned their attention toward needles and discovered via advanced X-ray technology that when tattoo ink contains titanium dioxide — a white pigment that is mixed in with bright colors like blue and red — it can erode the needle. Importantly, they did not find this reaction when examining needles dipped into black ink.
The team also used scanning electron microscopy to confirm the presence of abrasion on needles with titanium dioxide, which they applied to needles before and after they were used to tattoo a piece of pigskin. At times the needles contained the titanium dioxide-filled white pigment, and at other times the needles contained black ink. In the instances that the ink contained titanium dioxide, the tattoo needle revealed a high level of wear.
According to co-author Bernhard Hesse, Ph.D., a visiting scientist at ESRF, this proved that “it is beyond doubt that the metal particles derived from the tattoo needle as a result of pure mechanical grinding.”
To see how this mechanical grinding can actually turn into an allergy, the team examined tattoo particles in human skin and lymph node sections taken from deceased donors. In samples that contained bright particles — samples that contained the white pigment — they found evidence of steel particles ranging from 50 nanometers to 2 micrometers in the lymph nodes. When they subsequently and specifically examined the skin tissue from a patient who was known to suffer from a tattoo-related allergic reaction, they found “both [iron] oxide pigments as well as abraded steel particles in the inflamed skin.”
The authors acknowledge that far more research is needed to definitively say the allergic reactions people experience are linked to needle abrasion, but this study is a sign that more is happening in the body when a person gets a tattoo than meets the eye. They can’t determine the exact impact tattoo needles have on human health now, but they call for more long-term epidemiological studies that monitor the health of a large sample of human subjects.
Results: Here, we report the deposition of nano- and micrometer sized tattoo needle wear particles in human skin that translocate to lymph nodes. Usually tattoo needles contain nickel (6–8%) and chromium (15–20%) both of which prompt a high rate of sensitization in the general population. As verified in pig skin, wear significantly increased upon tattooing with the suspected abrasive titanium dioxide white when compared to carbon black pigment. Additionally, scanning electron microscopy of the tattoo needle revealed a high wear after tattooing with ink containing titanium dioxide. The investigation of a skin biopsy obtained from a nickel sensitized patient with type IV allergy toward a tattoo showed both wear particles and iron pigments contaminated with nickel.
Conclusion: Previously, the virtually inevitable nickel contamination of iron pigments was suspected to be responsible for nickel-driven tattoo allergies. The evidence from our study clearly points to an additional entry of nickel to both skin and lymph nodes originating from tattoo needle wear with an as yet to be assessed impact on tattoo allergy formation and systemic sensitization.