What do I need to know about tattoo health risks?
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Fresh for everyone. Aplican restricciones en combustible. This is a CBC Podcast. Hi, I'm Dr. Brian Goldman. Welcome to The Dose. Well, tattoos are ubiquitous. A 2024 survey found that a third of Canadians have at least one tattoo. To me, it seems like everybody under the age of 30 has at least one, if not many.

This being a health podcast, we worry about the risks. A growing number of studies show an association between tattoos and cancer, for instance. But how big a risk is that? So this week we are asking, what do I need to know about tattoo health risks? Hi, Yelena. Welcome to The Dose.

Hi, thanks for having me. So how the heck did you get to be a tattoo expert? Well, I don't consider myself as a tattoo expert, but I think every dermatologist ends up being a little bit of a tattoo expert because tattoos, by definition, are injected into the skin. And as a skin doctor, I will see any sort of tattoo reactions and reactions.

I will also be usually asked questions from the patients about the safety of tattoo in my office. Okay, you're the right person to talk to. But before we begin, can you give us a hi, my name is, tell us what you do and where you do it. Hi, I'm Dr. Jelena Nechiporuk. I'm a dermatologist, assistant professor of dermatology at McGill University Health Center, assistant professor of experimental medicine at McGill University Health Center, and scientist at McGill University Health Center Research Institute.

For those of us who don't have tattoos, how are they made? Tattoos are usually made of an ink, which is a coloring agent. A coloring agent comprises usually up to 60% of the mass of the tattoo ink. And it can be made either of metal salts,

Or organic paints, which is kind of similar to the paints that have been used to paint our houses, for example. And the rest of the weight will be usually comprised of preservatives, so to make sure that the tattoo ink will not give a bacterial or fungal infection. And vehicles, which usually is to make the tattoo ink durable.

flow well into the skin. We are here to talk about the risks, but what can you say about the benefits of having a tattoo, psychological and otherwise? Because, you know, as a dermatologist, you are concerned with aesthetics. Yes, I would say that we're mostly concerned about self-acceptance and the happiness and quality of life for our patients and their mental health.

For many patients, a tattoo will usually represent kind of an emotional, there's usually an emotional reason why they will do tattoos, whether it will be to tattoo the names of their loved ones,

or something that has culturally, religiously, or socially important meaning for them. And of course, we also see a lot of tattoos right now. They're being used to camouflage, by example, surgical scars or potentially traumatic life events. This is just an aside, but recently I interviewed a former paramedic who's now a wilderness rescue specialist.

He has a tattoo on his forearm that depicts the last rescue when he participated with a man who later died and he actually tried to resuscitate him. So tattoos can have important psychological meaning, emotional meaning for people who get them.

And I wanted to start with that because we're going to be talking about the risks, but there are clearly benefits. But from your standpoint, what is the single greatest harm that can come from getting and having a tattoo in terms of numbers and practicality? In that regard, probably the greatest harm will be tattoo regret because about 25% of patients who end up having a tattoo done, they usually end up regretting it and they want to remove it. So in terms of number, 15%.

For the best evidence in 2025, this will be the greatest evidence. Of course, otherwise, most of patients will experience some sort of pain or inflammation at the beginning of tattoo, which is completely normal because the tattoo is being injected into the skin and there will be a healing phase that will follow. Sometime in the first weeks, there will be a swelling of the lymph nodes because some of the ink will migrate to lymph nodes.

But this is usually all minor and not really concerning. The concerning things is actually potentially what we don't know about tattoos. And I think personally, from me as a dermatologist, what concerns me the most is what will we learn in the future about the association or potential association between cancer and tattoo exposure. I want to talk about some of the more common risks that are probably not life-threatening, but will be noticed by patients. Let's start with

with the fact that some people are allergic to tattoo ink. Describe a common allergic reaction that they might get. - Well, the most common allergic reaction that I will see is the patient will present with bumps. So the skin will become thicker and elevated with the tattoo, and it will usually be localized to a color tattoo, particularly red. Red tattoos are responsible for like 97% of allergic reactions within the tattoo.

So that can happen anytime between one month after tattoo to years after tattoo. I've seen patients that develop this 10 years later, by example.

And this will be the most common reaction. But otherwise, what we can also get will be some scaly rashes. So there will be some scaliness and redness and itchiness that can develop on the tattoo side. And similarly to the bumpy reaction, it can also take anywhere between a couple of weeks after the tattoo to years, years later.

And the reason why it can also take years sometimes is that most of the time we're not really allergic to the ink that is being injected into the skin, but the ink gets transformed in the skin to an allergenic protein or peptide. And this is what our immune system will recognize and give like the localized reaction. I've never seen any systemic allergic reaction to a tattoo ink, even though it's been injected into the skin.

And finally, the other type of allergic reaction that I might have seen just like once or twice in my career so far would be an ulceration. So actually the reaction is so severe, then the skin literally like ulcerates, erodes onto the tattoo side. You mentioned that red ink seems to be riskier. What is it about red ink that would make it more likely to provoke an allergic reaction? I'm not sure there is a lot of science to really like understand why the red in particular, but...

Some of the red tattoos will use cadmium, which seems to be a little bit more allergenic. And the other hypothesis is because, again, of the dye pigment that is used in red tattoos, which are azo dyes.

And azo dyes can undergo transformation in the skin because they're sensitive to the effects of ultraviolet radiation and even laser tattoo removal. So they can transform into other chemicals in the skin, which can become more likely allergenic. Is it always the ink or what's in the ink to which patients are allergic? What about the solvents and the preservatives that are also baked into the tattoo? Oh,

Oh, absolutely. I would say preservatives are very, very important. There was a recent study that looked into the preservatives. And interestingly, preservatives such as MCIMI or methylchloroisothiazolinone and methylisothiazolinone, which has been popular in the media for the last couple of years, they have been commonly implicated in allergic tattoo reactions. And interestingly, they are usually never listed as an ingredient of a tattoo ink.

So some preservatives are definitely a common allergen, and they may not be on the list of ingredients of the tattoo that is being injected. You mentioned that some of these ingredients are not listed. Why is that? Is this a regulatory issue? I think so, because in Europe now, they really have to disclose all the ingredients of tattoo inks, because all the inks need to undergo approval.

And there is a limit of some of the potentially harmful ingredients and some ingredients can just simply not be used. But we do not have the same legislation in Canada and the United States for now. You've talked about the allergic reactions, some of which can appear within days, some of which might take years to develop. If somebody comes to you and says, I have had...

An allergic reaction. Here you can see I've had a bumpy allergic reaction to a previous tattoo. Are there any steps that people can take to prevent those allergic reactions on the next tattoo? I think the best single next step will be not to have a tattoo. Oh, really? Yeah.

Yes, but otherwise, really, most of the tattoo allergic reactions are specific to usually the red color or the color tattoo in general. Usually, black tattoos are less of a concern for allergic reactions. I have personally never seen a reaction to the carbon black tattoo so far. I've seen other types of reactions to the carbon black tattoo, but not the allergic reaction. So, carbon black tattoo would be safer? Yes.

What reactions have you seen in response to those? So I have seen for the carbon black tattoo sarcoidal reaction, which is a type of immune reaction that can present in the skin, but also beyond the skin. It can affect the lungs and the eyes and the joints, just like the immune-mediated condition called sarcoidosis. This is not a common complication. We're speaking about anecdotal cases, probably under 1% of individuals who have a tattoo.

But this one can be potentially serious. And then the carbon black tattoo is actually a class one carcinogen. Hence, I am not comfortable recommending somebody to get a black tattoo ink that contains carbon black at this point until there will be additional studies that can either reassure us saying there's really not that much association between cancer and tattoo, or maybe they will say that there is.

Since you've mentioned cancer, let's dive right into that. Studies have found an association between tattoo ink and cancer. You've already talked about carbon black, including a study earlier this year by researchers in Denmark and Finland.

What do we know about the relationship between tattoos and cancer? The first line of evidence that we have is just about the toxicological studies of the tattoo ink themselves. And carbon black, which is the most commonly used pigment in black inks, and which is, I believe, the most common color in tattoos overall.

It's actually produced through the incomplete combustion of petroleum products. And it usually contains polyaromatic hydrocarbons, basically derivatives of benzene type of thing. And this is classified by International Agency for Research on Cancer as group 1 carcinogen. When we say group 1 carcinogen is that we know that this particular ingredient has very strong proof that it can cause cancer in humans.

However, this being said, these ingredients have not really been studied extensively for when they are injected into the skin. Most of the evidence to call this the Groupon carcinogens come from epidemiological studies and studies when there is exposure between the black carbon down products and ingredients and respiratory route, so when they are breathed in.

or when they are ingested by oral route. So the risk from the intradermal injection during tattooing remains poorly characterized.

However, the concern is that we do know that for individuals who are tattooed, there will be some tattoo pigment that will migrate from the skin to the lymph nodes and internal organs. It happens pretty much in everyone, but the extent of this migration, how little or how much, will depend on many, many, many variables, such as the size of the tattoo and some individual level risk factors.

But there is a study that was published relatively recently that have shown that by week four, there will be a reduction in the tattoo from the skin by at least 30%. So we would expect that potentially a range of one third of the tattoo ink has migrated from the skin elsewhere. You've described quite beautifully the deficiencies that we have in terms of scientific research, as I understand it.

There is an association between having tattoos and potentially having skin cancers. But that's based on what you've called epidemiologic studies, which are population studies. So I gather that's just comparing populations that have tattoos with populations that don't have tattoos and seeing what pops up as a disease or diseases in the people who have tattoos compared to those who don't.

And no interventional or controlled studies. And of course, any scientific studies where researchers actually give tattoos to one group and not to the other group, it would be very hard to blind that study and then see what diseases show up. I'm sure there hasn't been a study like that.

No, no, you're absolutely correct. There's not a study like that. And I'm not sure if there will be. So it's possible that the best line of evidence that we will have will come from observational studies, but we also will need some mechanistical studies to actually show that the Tide 2 itself will be potentially carcinogenic, which can be done in, by example, mice models or animal models.

But the lines of evidence we currently have, they really come from observational studies, exactly like you mentioned. In regards to skin cancer,

There is a systematic review, which means that researchers searched the literature from the inception of human publications up until now, and they've pulled all the cases of cancer rising within the tattoo to date, and they've identified about 160 skin cancers, which can be squamous cell carcinoma, melanoma, etc., that arise actually within the tattoo. And there seems to be a rising trend, so more and more of these cases being published.

However, this level of evidence is very limited by design because

At this point, if there are already 160 cases published, if I would have a case, which I actually did have a case of a patient who presented with a four centimeter skin cancer that arose within the tattoo, literally within like four months of having the tattoo, I will not publish this case because there's already 160 cases published. So I will not even be able to publish this. So this is something that will be called kind of a publication bias. So

So the best level of evidence that is really coming is from this observational studies, exactly like you've mentioned. I believe you mentioned early on the Danish study. So I feel this one is probably one of the most interesting. It was just published in 2025 and it looked at twins.

So some twins that will have a large tattoo or a small tattoo and the other twin will not have a tattoo. And they compared the risk of skin cancer and blood cancer, like lymphoma, in these patients. And what they did find is that large tattoos that are greater than the size of a palm seem to have an increased risk of developing lymphoma, which is a type of lymph node,

a rise in cancer, and the risk seems to be two to three folds. So basically somebody who has a big tattoo has a two to three fold increased risk that the twin that has no tattoo of developing a lymphoma

which still basically probably on an individual level will present a small risk for that individual. And in regards to skin cancer, the risk was similarly increased. So the individual who had a large tattoo bigger than the size of a palm was found to have a 2 to 2.5 increased risk of skin cancer that can arise within the tattoo or elsewhere.

And this is usually what's also for us, a dermatologist, will be a challenge to see this association because sometimes we're not even aware that the patient has a tattoo somewhere if they're coming to show us their hand, by example, or a skin lesion on their face. And then when the skin cancer rise in an area that it's other than tattoo, unless there is big studies to support this association, it's really, really hard to just speak about any causality at this point.

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You saw a cancer that arose from a tattoo, but that doesn't tell you how often people have tattoos and a cancer never arises from them. So what you're saying is, yeah, it's possible that a cancer, a skin cancer could arise directly from a tattoo, but that doesn't tell you how often it happens. I would say that it must be extremely rare because I have been a dermatology resident from 2012 to 2017. This means that I was already seeing patients on every single day.

from this period of time. And then from 2017, I have been in clinical practice. So now it's been eight years and I have only seen this arising twice since 2012. So this being said, if I've only seen a skin cancer rising in the tattoo twice, that means that it's very, very, very rare. But the issue here is that if we have a product that is being injected into the skin, that will migrate beyond the localized area of the skin and

and it's potentially cancerogenic, which we know carbon black is and the red dyes like azo dyes are, then we could theoretically have an increased risk of developing cancer in the skin elsewhere.

And in the lymph nodes, the current level of evidence suggests there is a possible association, but association does not mean causation. And sometimes the risk factor can be so complex that it takes more than just a tattoo. It may take tattoo plus sun, may take tattoo plus sun plus smoking. So I feel there is a lot for us to learn in the future.

Can we say in general that the more tattoos you get, the greater the risk? The Danish studies have looked into that. And this is one of their conclusion is that the size of a tattoo that it's larger than a palm seems to be the really one that is potentially more associated with cancer of the skin and lymph nodes. We haven't talked at all about the risk of infection. So what can you say about that from getting a tattoo?

The risk is usually lower than 5%. And this is like any skin procedure, a piercing of the skin, a skin biopsy, skin surgery, anything that we cause trauma to the skin can potentially lead to infection. Of course,

Potentially the added challenge of a tattoo is that sterile equipment needs to be used as it's being injected, which to the best of my knowledge, it's usually not a concern in Canada. So in this case, the chronic infections like hepatitis B, hepatitis C, HIV should not be a problem unless there is a needle prick injury between the person who gives the tattoo and the person who receives the tattoo.

But the common infection, like gram-positive, like staphylococcus bacterial infection, that can happen with any type of skin injury. So this is what can be seen. But for all the other types of infection, the risk is really very, very, very low. Notwithstanding this conversation with all the potential risks, I'm assuming that people listening, if they're thinking about getting a tattoo, I'm not sure that this conversation is going to dissuade them.

But if they are absolutely determined to have a tattoo, what are the precautions that you would recommend with them? Well, the first thing is that right now, I don't think we have enough evidence to really discourage people from getting a tattoo. So the only individuals in my practice that I discuss the tattoos is individuals who already are

are at increased risk of skin cancer. In this case, we just don't want to increase that risk even further. So I see patients with genetically inherited risk of cancer in my genetics clinic, genodermatology clinic to be specific. So in those patients, I will discourage them from getting a tattoo unless they absolutely, absolutely need one or absolutely want one because I would want to know more about their safety for patients who are already at increased risk.

But for individual, you know, like probably all of us where we're not particularly at increased risk, there's not enough evidence at this point to really say nobody should get it. So in this case, before getting a tattoo, just make sure that an individual go to a licensed tattoo artist with good hygiene practice. In this case, I would say probably pretty much everyone in Canada will be in this category.

An individual is allowed to ask about ink brands and ingredients that are being used. But in this being said, sometimes some ingredients are actually not disclosed on the bottle of that tattoo pigment. And the tattoo artist may not even know the hidden ingredients. I would potentially avoid red and yellow pigments if the individual is prone to allergies. And then I would not tattoo over moles or skin conditions.

potentially if the tattoo is done on top of an eczema or psoriasis skin that could potentially increase risk of allergic reaction and infections. And the issue with tattooing over a mole is that, God forbid, if this mole is not a mole and it's early skin cancer, then being able to track or...

or observe this mole will be just physically challenging because there is a tattoo on top of it. So for individuals who I do skin exams with my dermatoscope and there is a mole that it's right in the middle of a black tattoo, it's really hard for me to look into the pigment of this mole because

Last question I want to ask you. Some people hearing this podcast might decide to get their tattoos removed. What's the safest and most effective way to do that? I think usually laser removal of a tattoo is pretty safe. But if we're concerned about cancer risk, whether we remove the tattoo or not, I'm not 100% sure at this point if there will be a difference because we actually just need more studies.

But laser tattoo removal is usually safe. The alternatives of laser would be excising the tattoo, which usually will be cosmetically quite unpleasant because it will usually lead to large scars. So at this point, I can't really recommend that. And most of the tattoo removal places in Canada, they know what they're doing and they can do a very good job in removing the tattoo. Do you eliminate your risk of skin cancer by getting the tattoo removed?

I personally don't think so, but there's no data to say yes or no at this point. Your enthusiasm for the subject is infectious, and I hope more infectious than getting tattoos. Dr. Yelena Nechiporuk, thank you so much for speaking with us on The Dose. Thanks so much for having me.

Dr. Jelena Nechiporuk is an assistant professor at McGill University's Department of Medicine. Here's your dose of smart advice. Tattoos are made by permanently inserting colored ink mixed with water, solvents, and preservatives into the skin using needles and other piercing devices. Permanent eyebrows, eye, and lip liner are also examples of tattoos. Immediately after getting a tattoo, it's common to have redness, swelling, warmth of the skin, and minor discomfort, which can last for a day or two.

Between 1 and 6% of tattoos can get infected with bacteria, causing increased redness and tenderness around the tattoo, as well as fever and chills. These require antibiotics prescribed by a health care provider. Allergies are less common. The most immediate occur days to weeks after getting the tattoo, causing redness, scaliness, and itchiness. Far less common reactions include scarring of the skin and pronounced bumpiness, which may occur weeks or even years later.

The risk of tattoo needle injuries is very low since the needles used for tattoos in Canada are disposable sterile needles. When needles are reused and when other infection prevention and control practices are not followed, you could be infected with HIV, hepatitis B or hepatitis C. Tattoos are associated with a risk of skin cancers, including melanomas and basal cell carcinomas. We don't know how frequently these occur.

It is safest to get a tattoo from a studio inspected by the local public health unit. Your tattoo artist should ask you if you have any allergies to pigments, latex and antiseptics and should provide information about the procedure and associated risks. The tattoo artist should also ask you for your contact information for record keeping purposes. See a health care provider if you think you're having an infection or an allergic reaction.

Notify the tattoo artist and ask for the brand, colour and any lot or batch numbers of the ink or solvents. That helps determine the source of the problem and how to treat it. Keep in mind that some of those added ingredients such as preservatives may not be known. Before having an MRI, let your healthcare provider know if you have a tattoo as the procedure may cause burning or swelling in or around the tattoo. Laser tattoo removal is becoming increasingly popular.

We don't know how pigments break down after laser treatment. Some laser tattoo removal procedures may leave permanent scarring and may fail to remove the tattoo completely. It's not clear to what extent removing a tattoo reduces the risk of skin cancer. And now, a program note. Next week on The Dose, we answer your questions on how the federal government is responsible for health care. Send any questions you have to thedoseatcbc.ca.

We'll get you what you need to know in time for the federal election. If you have topics you'd like discussed or questions answered, our email address is thedoseatcbc.ca. If you liked this episode, please give us a rating and review wherever you get your podcasts. This edition of The Dose was produced by Samir Chhabra. Our senior producer is Colleen Ross. The Dose wants you to be better informed about your health. If you're looking for medical advice, see your health care provider. I'm Dr. Brian Goldman. Until your next dose.

For more CBC Podcasts, go to cbc.ca slash podcasts.