Though we don’t know as much about tattoos as scientists like Swierk would like to, we do have some knowledge of how the ink is made and interacts with the body.

Swierk and his team interviewed 100 tattoo artists and discovered they had preferred brands of ink but were unsure of the contents. The researchers were looking at the particle size and molecular composition of pigments and noted that there were ingredients in ink not included on labels, including azo-containing dyes.

Swierk says that azo-containing dyes may not pose concerns initially, but they can break down when exposed to ultraviolet light from the sun or even laser removal and bacteria.

“The pigment may be safe, but when you shine a light on it, it may break down into new molecules,” Swierk says. “Do we need to be concerned with new molecules?”

A final report from the 2016 Joint Research Centre (JRC), an independent agency that provides scientific advice in the European Union, noted that azo pigments could release carcinogenic compounds in the skin, especially if exposed to UV radiation or laser.

Azo-containing dyes were present in 23 of 56 different inks analyzed.

Additionally, the team’s analysis indicated that about half of the 16 inks analyzed using electron microscopy contained particles smaller than 100 nanometers.

“The concern is that when you have a particle that gets below a certain size limit, that particle can get into cells, damage them, and it might lead to problems like cancer,” Swierk says.

Swierk says the new research may seem alarming, but he does not want individuals to panic. He also doesn’t like using the word “health risks” when discussing his research on tattoos or others.

“Tattoos have been around a long time,” Swierk says. “There must be some level of inherent safety around them, but we’re trying to understand if there are things we should be looking for or concerned about as the popularity around tattoos and the market around inks expand. Are there things we should be looking around more closely?”

Swierk says his research only scratches the surface of tattoo ink ingredients and potential concerns. But it also builds on a small body of knowledge. Tattoo inks can also cause:

• allergic reactions
• infections
• irritation

An allergic reaction may not seem like a big deal. People with mild seasonal allergies may be able to find relief with over-the-counter drugs, and those with a shellfish allergy can refrain from ordering oysters.

But Swierk says tattoo ink-related allergic reactions can be debilitating and may not show up for months or even years. The reason is unclear, but providers should take the issues it can cause seriously.

Susan Richardson, Ph.D., a chemistry professor at the University of South Carolina, knows of instances where it led to hospitalization.

And research indicates that even when hospitalization isn’t required, tattoo-related reactions like ink allergies can be painful. A 2015 study suggested that the pain associated with tattoo reactions was similar to the discomfort experienced by people with skin conditions such as eczema and psoriasis.

“When you have an allergic reaction to tattoo ink, it’s a constant thing and can be very painful,” Swierk says. “It’s embedded in your ink.”

Swierk says red ink has the most reports of allergic reactions, followed by yellow ink.

However, since tattoo ingredient labels aren’t accurate and the FDA doesn’t regulate them, it’s difficult to say that someone is allergic to all red pigment.

“You don’t know what you’re getting,” says Richardson. “It’s buyer beware.”

Swierk says it’s challenging to pin a diagnosis, such as cancer, on tattoo ink based on the lack of research currently available.

“If someone is having a health problem, it’s difficult to say, ‘Yes, that’s related to your tattoo,’” he says.

Still, it’s important to seek care if you notice issues, particularly around the tattoo sight.

Bruce Ruck, PharmD, the managing director of New Jersey Poison Control Center at Rutgers New Jersey Medical School, advises people to call their doctors if:

• they are in pain
• the pain is getting worse
• the area feels hot

“[Treatment] depends on severity, size, and problem,” Ruck says. “If somebody develops a reaction, they may think they have an allergic reaction, but in reality, it may be an irritation or infection.”

Ruck stresses this confusion is why it’s essential people don’t self-diagnose the issue and instead seek help from a dermatologist or cosmetic surgeon. A primary care physician can provide a referral. He also recommends involving the tattoo artist, who may be able to provide information on the ink used.

Treatments the provider may use include steroids or antihistamines, Ruck says.

Tattoo removal can take several weeks and typically involves using a laser. It may not completely remove the tattoo, and it’s unclear whether laser removal could cause more harm than good. As Swierk and the JRC indicated, the procedure could lead to carcinogenic compounds being released into the skin.

But a 2016 study indicated that laser interventions had some degree of success for people experiencing reactions to red tattoo pigment.

There may be concerns associated with tattoos, but the bottom line is that they are growing in popularity. Swierk says we also don’t know definitively whether or not ink ingredients do pose risks, but people can still control for certain factors to decrease their risk of having tattoo-related issues. Experts share these precautions include:

• ensuring the tattoo artist is professional and experienced
• assessing the sanitation of the artist’s shop and processes
• understanding aftercare
• speaking with a healthcare provider first, particularly if you have known allergies
• consider skipping certain colors

Though there is no federal certification standard for tattoo artists, states and municipalities often have standards for licensing and sanitation of a facility. Shops will often display licenses and inspection stickers noting they have received training and their shop meets local health standards. Swierk says you can ask to see those and that people can call local health departments to inquire about violations. He also recommends asking for referrals from family and friends who had a positive experience with an artist with a sanitary shop.

When you get to a shop, Ruck says people can essentially act like inspectors themselves. He suggests noting whether:

• it is neat and clean
• the artist is opening materials, like gauze, from individual packets, indicating has not been used
• the artist appears healthy and is not coughing or sneezing

The artist will recommend aftercare, and it will vary. It usually involves cleaning it and covering it. Ruck suggests getting new materials to care for the tattoo to lower the possibility of issues.

“Make sure cream and ointment is new and fresh, not expired, to reduce the risk of irritation and contamination and increase the efficacy,” Ruck says.

Individuals with a history of allergies will want to take additional steps.

“People with any type of allergy should speak with an allergist, immunologist, or physician before getting a tattoo,” Ruck says.

Given that specific blue and green pigments raised enough flags in the EU to get banned and red and yellow have a higher likelihood of allergies, Swierk says people may consider skipping those pigments or going with an all-black tattoo.

“There are people with red, blue, yellow, and green tattoos without health problems or medical concerns,” Swierk says. “I don’t want to imply those colors are definitely problematic…If you are concerned, use black inks. Work with thoughtful professionals. That can mitigate those concerns.”