Tattoo & Chemistry: Is It Advisable To Adopt The Ongoing Trend? Think Before You Ink

DR. BHASKAR CHAKRABORTY Professor of Chemistry Sikkim Government College (NBBGC) An Extension Centr

A “tattoo” is a permanent kind of body art. A design is made by puncturing the skin with needles and injecting tattoo ink into the deep layer of the skin.Tattooing has become a popular global trend in most of the countries of the world with the highest prevalence rates of up to 30-40 % in the adult population younger than 40 years. Common tattoo inks may contain heavy metals, polycyclic aromatic hydrocarbons and primary aromatic amines, toxic if exceeding permissible limits. It is estimated that about 14.36 mg of ink is injected per cm² of skin, at a depth of 1-3 mm. The injected pigment is internalized by neutrophils, fibroblasts and macrophages or dendritic cells. About 60-90 % of the pigment is then transported to the lymph nodes via the lymphatic system and to other organs, such as the liver, spleen and lung, through blood. Adverse reactions can be immediate (irritation, infection, inflammation of the skin), delayed (hypersensitivity reactions), and can result in long-term complications (fibrosis, granulomatous changes, systemic inflammation and sometimes malignant diseases such as lymphoma).

Tattoo, from a chemistry perspective is essentially a permanent coloration of the skin achieved by injecting pigments (dyes) made up of various chemical compounds. Tattoo inks contain a variety of pigments, including inorganic compounds like iron oxides (black), titanium dioxide (white), cadmium sulfide (yellow) and organic dyes (many colors).Nowadays, organic pigments are mainly responsible for the colour splendour on the skin. During tattooing,these chemical compounds entersinto the dermis layer of the skin, where they remain trapped and visible due to their stability within the body tissues. The color of the tattoo is determined by the specific chemical composition of the ink used.  The pigment is suspended in a carrier fluid, usually a mixture of water, alcohol and glycerin, which helps to deliver the ink into the skin during the tattooing process. When the needle punctures the skin, the pigment particles are deposited in the dermis layer, where they are engulfed by cells called macrophages which then become "locked" in place, making the tattoo permanent. 

There are various issues and concerns regarding the entry of chemicals during tattooing process. Some tattoo inks may contain potentially harmful chemicals like heavy metals (lead, mercury, cadmium) which can cause allergic reactions or long-term health concerns depending on the quality of the ink and the individual's sensitivity. Pigments in tattooed skin can be identified by skin biopsy, chemical imaging and histochemical and immune histochemical analyses. Harmful effects of tattoo inks have been investigated ex vivo, in vitro, in vivo and recently in silicon application methodologies. Studies in humans mainly refer to case reports, but there are no epidemiological studies that would evaluate the potential links between tattoos and cancer or other disorders. As the safety of people getting tattoos primarily depends on the quality of tattooing products. In the long run, potential side effects of tattoos include allergic reactions to the ink, the formation of granulomas (small bumps around the ink), scarring, skin discoloration, potential for increased inflammation in the tattooed area and in rare cases, complications like keloids (abnormally large scar tissue) if someone is prone to them. All of these can depend on the quality of the ink, the artist's hygiene and your body's reaction to the foreign substance introduced into the skin. 

During tattooing severe allergic reactions may occur if the person under tattooing has not undergone allergy tests (Patch test).Even years after getting a tattoo, an allergic reaction to the ink can occur, often manifesting as an itchy rash around the tattoo site, with red ink being particularly prone to causing allergies. Small nodules or bumps can form around the tattoo ink as the body tries to encapsulate it as a foreign substance. Improper tattooing techniques or infections during healing can lead to visible scarring. The tattooed area may develop areas of lighter or darker skin compared to the surrounding area. Therefore, selecting a skilled tattoo artist who follows proper hygiene practices is very crucial to avoid all kinds of risk factors. Following the artist's instructions for post-tattoo care is vital to prevent infections and promote proper healing. 

One should be very careful about the characteristics of a good tattoo ink.  First and foremost, it must be a pigment colour that does not dissolve is encapsulated by the skin on the spot and remains there. It must be light-stable so that it does not fade over time.Ideally, it is a non-Newtonian fluid that is solid or liquid depending on shear forces. A non-Newtonian fluid is a fluid that does not follow Newton’s law of viscosity. This means that its viscosity changes when it is under stress or force. Examples of non-Newtonian fluids are: molten polymers, paint, blood, melted butter etc. This property is important when applying the ink under the skin. The art of tattooing begins with the first needle prick. Nowadays, modern fine-needle tattoo machines are used to insert the colours up to two millimeters under the skin with high stitch frequency without anesthesia because even trained tattoo artists are not allowed to anaesthetize. When the needle is inserted into the skin, the ink which is initially thick can flow easily into the skin layer under pressure.When the needle is removed, the ink becomes thick again and no longer runs. When the inserted colour comes to rest, the micro-fine colour pigments must not clump or coagulate. Tattoos are always a health hazard. They can cause allergic reactions, chronic inflammation, and even permanent photosensitivity, although classic tattoos with carbon or titanium dioxide pigments are generally the most tolerable.

The country with the most tattooed people is Italy (48%) followed by Sweden (47%) and USA (46%).  Much fewer are in Israel (25%), Turkey (30%) or Mexico (32%). In India, as per as current trends the young generation (age group 20 to 25) are obsessed in tattooing and the percentage is increasing from 24% to 27%. The aesthetic appeal of tattoos is certainly debatable but it is undeniable that a tattoo is a decision for life. Because once placed under the skin, it ideally lasts a lifetime. What long-term effects the colour pigments have on the body can hardly be assessed at present, as there is no representative clinical and dermatological research studies available.

What happens if someone wants to remove the tattoo from his body?Tattoo removal works are usually done using lasers which target the pigment particles, breaking them down into smaller fragments that can be absorbed and eliminated by the body.Individuals with a predisposition to keloids may develop raised, abnormal scar tissue around the tattoo. In rare cases, the tattoo ink might cause discomfort or interfere with the quality of an MRI scan. Ultimately, it is everyone's own decision to get a tattoo as beautiful and meaningful tattoos can be. However, anyone who undergoes such a procedure should be aware that the “Colour Chemistry” literally goes under the skin for a lifetime and the risks are incalculable.

Courtesy:

International Agency for Research on Cancer, World Health Organization Research on Potential Long-Term Health Effects of Tattooing (2018).