"As a surgical doctor who deals with the consequences of tattoos, it made me wonder why my son would even think about one."

OPINION: My concern about the health implications of a tattoo resurfaced when my 16-year-old son asked me how I would feel if he got a tattoo.

Since he was a pretty switched on young man, I asked him if he knew what the risks were - especially the medical ones - while trying to hide my shock and horror as a doctor who has treated many tattoo complications.

Yes, he's heard me talk about allergic reactions, how they can form big scars, become infected - I've even shared the stories of having to drain pus from some of them.

But that doesn't happen to many people and everyone is getting "inked", he tells me. "It's really cool".

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It does seem like everyone is getting tattooed. In New Zealand, one in five people have one - that's close to one million tattooed people and one of the highest rates in the world.

As a surgical doctor who deals with the consequences, it made me wonder why my son would even think about getting a tattoo, having heard the horror stories.

UNSPLASH/SUPPLIED "I once treated a patient who had been to a tattoo parlour in a shed, where the skin had been prepared with an every day cleaning wipe."

Worldwide, 1 in 7 tattoos get infected with a bacteria or virus like Hepatitis B and C, or HIV 2 or 3. But part of youth rebellion can be to ignore consequences. Social media doesn't help; constantly featuring celebrities and sports people covered in tattoos. This makes them seem cool, glamorous and safe.

While the "cool" factor was a monster that would be hard to defeat, I had to try - with scientific evidence - to educate my son what he was really letting himself in for.

I shared with him photos of my personal encounters with tattoos; the bacterial and fungal infections, hypertrophic scars where mounds of skin had grown, a video of pus draining from an infected tattoo on a patient's back. It was quite dramatic.

Parlour hygiene is another concern. A review of over 200 Australasian tattoo parlours in 2018 found just 20 per cent were compliant with both hygiene standards and ink usage, while an American study identified at least 22 skin infections related to contaminated ink.

One outbreak in New York found Mycobacterium chelonae​, a relative of the bacteria which causes tuberculosis and leprosy, residing in ink ready to be passed from customer to customer. That's scary, especially as some of these bacteria are rapidly becoming antibiotic resistant.

In New Zealand, there is no definitive regulation or process requiring tattoo ink be sterile. A consumer can only take the company or artist's assurance that they are.

The major concern was the presence in these inks of polycyclic aromatic hydrocarbons (PAHs) - a group of chemicals known to cause cancer. These nasty PAHs were found in more than one-fifth of the samples tested and in 83 per cent of the black inks tested. Also, it found not one colour pigment had ever been approved for injection into the skin.

More startling perhaps, was the finding that the azo colour pigments used in nearly all inks had been shown to release potentially carcinogenic aromatic amines which, when exposed to the sun's UV rays or laser irradiation, increased the risk of skin cancer. Other elements found in inks used to give them colour all have cancer potential . These may take years to cause problems but clearly need to be part of informed consent when getting a tattoo.

I once treated a patient who had been to a tattoo parlour in a shed, where the skin was prepared with an everyday cleaning wipe. After the inking, the arm was wrapped in non-sterile cling wrap and the patient told to leave it on for two days before removing it. After 24 hours and with the patient's arm red and throbbing, I removed the cling wrap to treat the infection. It had sealed all the bugs in an airtight environment perfect for breeding.

Unfortunately, this was not a one-off case. Backyard parlours can represent up to 10 times the number of registered, professional ones.

Those who get cultural tattoos don't escape unscathed either; one patient had accompanied whānau to a local marae, where she and two whaea received tā moko - using the same ink without any sterilisation in between. She was tested for Hepatitis C, which was fortunately negative - unlike others who I have had to treat.

UNSPLASH/SUPPLIED "In an age where we surrounded by "cool" inked celebrities what do you say when your kids want to be like them?"

And it's not just hygiene. According to a European Commission study, some inks contain ingredients with cancerous potential - including a mixture of many unregulated chemicals. The Australian Government's review into the safety of tattooing looked at 471 different tattoo inks used in Australasia, and found they were made up of 89 unregulated chemicals.

Tattooing creates a permanent image by using ink via tiny punctures under the top-most layers of skin - the painful part, I'm told. Researchers with the Federal Institute for Risk Assessment in Germany - using powerful x-rays - found tattoo needle particles such as chromium and nickel present in the skin and lymph nodes after tattooing. When mixed with ink pigments containing titanium dioxide, an abrasive agent commonly used in white tattoo ink, there was the potential to cause skin cancer.

There clearly needs to be more information circulated about the risks so that people can make an informed choice before getting inked. While there may be no controlled trials verifying cancer types for another 10 to 15 years, present information (colour, type, the percentage of skin covered) could be added to patient records about their tattoos. This would help give more information on the association or link between tattoos and health problems in years to come.

I worry the glorification of tattoo use on social media is overwhelming growing health concerns, and the medical profession needs to really start pushing back.

Hopefully, with more education and understanding of the risks, we can prevent significant potential future health problems which tattooing may create.

As for my son? Armed with all this information, he has decided against getting inked.

Big sigh of relief from Dad.

Dr Paul Anderson is a surgeon and lecturer who runs a free specialist review clinic in the Bay of Plenty. He's also the founder of Specialists without Borders, a not-for-profit organisation which takes high quality medical education into developing countries.