While tattoos have become increasingly popular, new research says they could give you cancer. Microscopic particles from tattoo ink can migrate into the body and wind up in lymph nodes, crucial hubs of the human immune system.
Chemicals in tattoo ink travel in the bloodstream and accumulate in the lymph nodes, which may cause them to become swollen and therefore hinder their ability to fight infections, a study found for the first time.
Controversial chemical titanium dioxide, which is added to tattoo ink to create certain colours, and even dyes lymph nodes, and has previously been linked to cancer, itching and delayed healing.
The tiny particles – measuring a few millionths to a few billionths of a centimetre – include molecules from preservatives and contaminants such as nickel, chromium, manganese and cobalt, researchers reported in the peer-reviewed journal Scientific Reports.
Tattoo colouring is composed of various organic and inorganic pigments, and can be contaminated with toxic impurities.
Besides carbon black, the second-most common ingredient used in tattoo inks is titanium dioxide, a white pigment also used in food additives, sunscreens and paints. The chemical has been associated with delayed healing, itching and skin irritation.
''When someone wants to get a tattoo, they are often very careful in choosing a parlour where they use sterile needles. Yet no one checks the chemical composition of the colours, but our study shows that maybe they should,'' said co-author Hiram Castillo, a researcher at the European Synchrotron Radiation Facility in Grenoble, France.
Scientists in Grenoble, joined by colleagues at the German Federal Institute for Risk Assessment in Berlin, used X-ray fluorescence measurements to identify particles in the skin and the lymph nodes, which are located in the neck, under the arms and along the crease between the thighs and the abdomen.
Only the tiniest, nano-scale particles made it into the lymph nodes – but this may be enough to affect health.
The researchers also used a technique called Fourier transform infrared spectroscopy to assess changes in tissue near tattoo particles at the molecular level. They reported ''strong evidence'' for both the migration and long-term deposit of toxic elements in the body.
Now that their presence has been established, the next step is to look for evidence of adverse effects, including inflammation, they said.
Study author Bernhard Hesse said, "We already knew that pigments from tattoos would travel to the lymph nodes because of visual evidence: the lymph nodes become tinted with the colour of the tattoo. It is the response of the body to clean the site of entrance of the tattoo.
"What we didn't know is that they do it in a nano form, which implies that they may not have the same behaviour as the particles at a micro level. And that is the problem: we don't know how nanoparticles react.''
Once a rarity outside of marginal communities, tattoos have become mainstream fashion accessories in recent years. According to The Guardian, by one estimate, some 40 per cent of millennials in the US have at least one tattoo, hidden or on display.