Tattoos and your health

Tattooing has increased in popularity over the last three decades and is now seen on individuals from a broad range of social classes and in nearly every country in the world.  

As getting tattoos becomes more common, for example one in three Americans have at least one tattoo, potential risks and side effects are more intensely scrutinized.   While various studies have determined the extent of health risks and medical complications associated with tattoos, one study went a step further to determine whether people are properly informed about medical risks and complications, and how the level of knowledge differs between people with tattoos and people without tattoos.

It is important to know what really happens to your body when you get a tattoo and to fully understand the process of what goes on under the skin.

The tattoo process:

Tattoos are permanent images in the skin, which are delivered by needles puncturing and injecting ink into the dermis, the second layer of the skin. 

A tattoo artist usually uses a handheld machine that acts much like a sewing machine, with needles that pierce the skin.  Modern tattoo machines can pierce the skin to inject ink at a frequency of up to 3 000 pricks per minute.  The ink-filled needles can push various colours into the skin, allowing the tattoo artists to create permanent designs and images, with some regarded as masterpieces.

What happens to the skin during tattooing?

Human skin is the largest organ in the body, made of water, protein, fats, and minerals.  The skin is comprised of three main layers, with different functions.

• The epidermis is the outer layer of the skin, which serves as a protective barrier and provides the colour of the skin.  It also continually makes new skin, to replace about 40 000 old skin cells that the body sheds every day. 
• The dermis is the middle layer and contains connective tissue such as collagen which makes skin cells strong and resilient, and elastin which keeps skin flexible.  Hair follicles are rooted in the dermis.  Blood vessels provide nutrients and nerve receptors help with the touch sensation.  Oil glands help to make the skin soft and smooth.  Sweat glands in the dermis releases sweat through skin pores to help control body temperature.   
• The hypodermis is the fatty (adipose) bottom layer that helps to regulate body temperature by preventing you from getting too cold or too hot.  It also cushions muscles and bones from injuries during falls or accidents and has connective tissue that connects layers of skin to muscles and bones.  The blood vessels and nerves in the dermis get larger in the hypodermis and branch out to connect the hypodermis to the rest of the body.

It is important that the tattoo ink is injected into the deeper dermis, as the epidermis (outer layer) of the skin is always shedding.  A tattoo in the epidermis will soon fade and probably only last a few weeks.

The dermis is very sensitive, and the tattooing process creates tens of thousands of tiny wounds, which pushes the body’s immune system into overdrive and into healing mode.  A team of blood cells called macrophages ae rushed to the site of the tattoo to remove the foreign substances, namely ink from the tattooing process.  (Macrophages are a type of white blood cell that surrounds and kills microorganisms and removes dead cells.)

Some macrophages remain in the dermis and allow the injected ink to remain visible, while other macrophages absorb ink particles and send them out through the lymphatic system, where they collect inside lymph nodes and result in dark spots.  In one such instance the operation of a heavily tattooed cancer patient, due to undergoing a mastectomy procedure, nearly went in an unexpected direction when her surgeons noted that her lymph nodes had turned black.  Fortunately, the surgeons realized in time that the dark colour was caused by broken down tattoo ink build-up in in the nodes.  An incorrect diagnosis could have led to treatment for malignant melanoma.

Health risks and potential side effects of tattoos:

One of the major risks associated with tattooing starts with the tattoo facility.  Unsterile equipment and needles increase the risk of infections in the tattoo area and can even result in the transfer of infectious diseases such as HIV and hepatitis. 

In addition, tattoo ink can become contaminated with mycobacteria, which can cause an infection that results in redness, swelling, itching, and raised red, pink, or purple blemishes in the area of the tattoo.  The area may become permanently scarred.

Studies have shown that nanoparticles are found in tattoo inks.  As nanoparticles are ultramicroscopic in size, they are able to penetrate through skin layers into blood vessels and travel with the bloodstream and could possibly enter organs and other tissue.  Some evidence from studies suggests (not proven yet) that these nanoparticles might cause nerve damage and might induce toxic effects in the brain, while some might be carcinogenic.

 It is well known that small ink particles pass into the lymph system and end up in lymph nodes, which may cause false identifications of cancer.

Modern tattoo inks might contain substances such as preservatives, shellac, aromatic amines, azo dyes, hydrochloride, ammonia, nickel, and food coloring.   These substances may cause problems for people who are allergic to one or more of these substances.

The individual receiving the tattoo needs to take proper care of the tattooed skin afterwards, to prevent infections.  The tattooing process damages the skin and causes blood clots to form around the broken blood vessels, resulting in bruises.  The swelling of the skin around the tattoo protects the area from any further injury and helps it to heal.

More serious adverse reactions to tattoos are less common and may include aseptic inflammation, allergic reactions, and hypersensitivity to the tattoo ink, especially red ink, but also to chromium in green ink, cadmium in yellow ink, and cobalt in blue ink.

Other risk factors are the forming of fibrous scar tissue, called keloids, caused by excessive repair in response to needle incision, as well as the formation of granulomas, which refers to an area of inflammation forming around tattoo ink.

Tattoo removal:

Over time, some individuals may regret getting tattoos and wish to have them removed.  Medical complications may also require tattoo removal, such as allergic reactions, hypersensitivity to the tattoo ink, keloids, and granulomas.

Tattoo removal by dermatologists is often more painful than tattooing and can leave scars.  Nowadays pulsed lasers are used to remove tattoos.  The laser energy passing through the epidermis is absorbed by the tattoo pigments, especially the dark pigments.

Laser treatment breaks down the larger pigments of the ink into much smaller particles, which are transported through the body and stored in the lymph nodes or other tissue.  The ink does not ever leave the body, although a portion is suspected to be excreted via the liver.

Conclusions:

A research project in 2018 found that a substantial portion of the 211 respondents had very little knowledge of the health risks and complications associated with tattoos.  There were practically no differences found between the 100 tattooed and 111 non-tattooed people regarding the knowledge of these risks.

Think carefully about getting a tattoo, as the potential risks and side effects should be carefully scrutinized.  Ensure the tattoo is done in a reputable establishment by properly trained individuals.  Further ensure that the tattoo artist takes the needles and tubes from sealed packages.  Ink should be placed in new disposable single-use cups.  The facility should have an autoclave (a heat-sterilization machine) and the tattoo artist should work with sterilized equipment.

While some individuals may experience allergic reactions to tattoos, most people only experience short term discomfort during the healing process.

As for any cancer risks, Popular Science recently (March 2025) pointed out that any link between tattoos and cancer would have been noticed by now in our increasingly inked world.

References:

Tattoos: Understanding risks and precautions.  2 March 2024.  Mayo Clinic.  USA.  (www.mayoclinic.org)

Tattoos: What’s happening under your skin.  Published 18 May 2018.  Southeastern Dermatology.  (www.drdoppelt.com)

Tattoos: What do people really know about the medical risks of body ink.  Published in the Journal of Clinical and Aesthetic Dermatology.  2018; 11 (3): 30-35.  (www.jcadonline.com)

Where does tattoo ink go in your body?  Published 1 March 2025.  Popular Science.  (www.popsci.com)

Skin.  Published online and reviewed 13 October 2021.  Cleveland Clinic.  USA.  (A nonprofit multi-specialty medical centre that integrates clinical and hospital care with research and education.)  (www.clevelandclinic.org)

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