Modern tattoos cause high concentrations of hazardous pigments in skin

Lessons learned in a decade: Medical-toxicological view of tattooing

Tattooing has been part of the human culture for thousands of years, yet only in the past decades has it entered the mainstream of the society. With the rise in popularity, tattoos also gained attention among researchers, with the aim to better understand the health risks posed by their application. 'A medical-toxicological view of tattooing'-a work published in The Lancet almost a decade ago, resulted from the international collaboration of various experts in the field. Since then, much understanding has been achieved regarding adverse effects, treatment of complications, as well as their regulation for improving public health. Yet major knowledge gaps remain. This review article results from the Second International Conference on Tattoo Safety hosted by the German Federal Institute for Risk Assessment (BfR) and provides a glimpse from the medical-toxicological perspective, regulatory strategies and advances in the analysis of tattoo inks.

Tattoo Pigment Biokinetics in vivo in a 28-Day Porcine Model: Elements Undergo Fast Distribution to Lymph Nodes and Reach Steady State after 7 Days

INTRODUCTION

Pigments of tattoo inks may over time migrate to other parts of the body. Inks kinetics are still poorly understood and little studied. The aim of this first study was to investigate the kinetics of tattoo inks pigment in tattooed porcine skin, which is closer to human skin than mouse skin studied in the past.

METHODS

Three animals were tattooed on the inner thigh and one animal served as untreated control. Skin biopsies were taken on days 7, 14, and 28 after tattooing. Animals were sacrificed on day 28 and homogenate samples of the liver, spleen, kidney, and brain, as well the local lymph nodes were prepared. All samples were analyzed for ink components using inductively coupled plasma-mass spectrometry. The ink itself was characterized by dynamic light scattering and matrix-assisted laser desorption-ionization mass analysis.

RESULTS

Titanium (212 g/kg), copper (6 mg/kg), aluminum (1 mg/kg), zirconium (1 mg/kg), and chromium (3 mg/kg) were found in the ink. Significant deposits of ink elements were detected in the tattooed skin when compared to non-tattooed skin from the same animal (mean ± standard deviation: titanium 240 ± 81 mg/kg, copper 95 ± 39 mg/kg, aluminum 115 ± 63 mg/kg, zirconium 23 ± 12 mg/kg, and chromium 1.0 ± 0.2 mg/kg; p < 0.05). Lymph node concentrations of titanium, copper, aluminum, zirconium, and chromium were 42 ± 2 mg/kg, 69 ± 25 mg/kg, 49 ± 18 mg/kg, 0.3 ± 0.2 mg/kg, 0.5 ± 0.2 mg/kg, respectively.

CONCLUSION

Deposits in skin were unchanged from days 7-28 indicating no redistribution or elimination. No significant deposits of ink elements were found in the liver, spleen, kidney, and brain. In conclusion, our findings confirmed distribution of elements from tattoos to regional lymph nodes, but neither to excretory organs, e.g., liver and kidney, nor to spleen and brain. Thus systemic internal organ exposure was not found.

Epidural analgesia and tattoos: a modified technique to minimise risks and improve safety

A healthy young woman with a sizeable lumbar tattoo was admitted to the delivery room in active labour at full-term gestation. She was experiencing strong, painful contractions and anxiety, concerned about the possible risks of receiving an epidural through a tattoo. Although there is little published evidence to suggest complications of performing an epidural through a tattoo, some studies report 'tissue coring phenomenon'. The anaesthesiology team informed the patient of the risks inherent in a traditional epidural and the potential long-term risks of receiving an epidural through the tattoo. Upon signing the informed consent form, the modified epidural technique was performed, and its administration proceeded without complications. A healthy boy was born 3.5 hours later in a vacuum-assisted delivery. This article describes the modified epidural technique designed to minimise tissue coring, and the results of 18 months of uneventful patient follow-up.

4-Aminobenzoic acid, 2-phenoxyethanol and iodine used as tracers in a short-term in vivo-kinetics study for tattoo ink ingredients: Mass spectrometry method development and validation

Tattoos have been gaining popularity in recent years, leading to a growing interest in researching tattoo inks and the tattooing process itself. Since the exposure to soluble tattoo ink ingredients has not yet been investigated, we here present the method validation for a short-term biokinetics study on soluble tattoo ink ingredients. The three tracers 4-aminobenzoic acid (PABA), 2-phenoxyethanol (PEtOH) and iodine will be added to commercially available tattoo inks, which will subsequently be used on healthy study participants. Following the tattooing process, blood and urine will be sampled at specific time points and analysed for these tracers. For this purpose, a method using liquid chromatography separation coupled to a quadrupole time-of-flight mass spectrometer (LC-QTOF-MS) in positive and negative ESI mode for the quantification of PABA, PEtOH and selected metabolites and an inductively-coupled plasma (ICP)-MS method for the determination of iodine were developed and validated. For LC-QTOF-MS analysis, the most applicable additives for LC eluents (0.01 % formic acid for positive and 0.005 % acetic acid for negative mode) were identified. Protein precipitation with acetonitrile was chosen for sample preparation. The methods were validated for selectivity, specificity, carryover, linearity, limit of detection (LOD) and quantification (LOQ), matrix effects, accuracy and precision, stability under different conditions and dilution integrity according to national and international guidelines with an allowed maximum variation of ±15 %. The LC-QTOF-MS method met the imposed guideline criteria for most parameters, however, some metabolites showed strong matrix effects. Validation of the ICP-MS method revealed that the KED-H2 collision mode is superior to the standard analysis mode due to enhanced method accuracy. The methods were validated for the relevant matrices plasma, urine, tattoo ink and tattoo consumables and proved to be applicable for the main target substances in the short-term biokinetics study. A proof-of-concept study showed successful quantification of iodine and PABA metabolites. The PEtOH metabolite was also quantified, but showed strong matrix effects in urine. Therefore standard addition was selected as an alternative quantification method.

TFOS Lifestyle: Impact of cosmetics on the ocular surface

In this report the use of eye cosmetic products and procedures and how this represents a lifestyle challenge that may exacerbate or promote the development of ocular surface and adnexal disease is discussed. Multiple aspects of eye cosmetics are addressed, including their history and market value, psychological and social impacts, possible problems associated with cosmetic ingredients, products, and procedures, and regulations for eye cosmetic use. In addition, a systematic review that critically appraises randomized controlled trial evidence concerning the ocular effects of eyelash growth products is included. The findings of this systematic review highlight the evidence gaps and indicate future directions for research to focus on ocular surface outcomes associated with eyelash growth products.

[Useful knowledge regarding tattoos]

The number of people with tattoos has continued to increase in recent years. In the USA about 23% and in Europe 9-12% of the population have tattoos. In the German media (2019) and by the infoportal Statista (2017), it is assumed that 21-25% of citizens have tattoos and that the trend is increasing (Statista 2018: 36%). Men and women wear tattoos equally. The age group 20-29 years dominates with almost 50% having tattoos. The following article describes the new regulations especially the REACH (Registration, Evaluation, Authorisation and Restriction of Chemicals) regulation, legal basis, and governmental controls on the subject of "tattoos". The composition of tattooing agents and testing options relevant for the user before and for the performance of tattooing are presented. Dermatologically associated diseases and testing procedures are listed. Since 70% of the population denies knowledge of this information even when they have tattoos themselves, this update is written as an overview for treating physicians and users.

Potential chemical risks from tattoos and their relevance to military health policy in the United States

We summarize and consolidate disparate sources of information about the practice of tattooing and its potential implications for military population health and policy. Each branch of the United States military has policies about tattoos for service members, but these have varied over time and do not cover health protection. The number of veterans receiving disability payments and the cost of those payments has been rising over time; the broad category of skin conditions accounts for 11% of disability claims. Any additional factor, such as tattoos that may increase the occurrence of adverse skin reactions, can substantially impact veteran benefit expenses and budgets. This may be a consideration for the military as it evaluates its policies related to tattoos among service members.

Are Some Metals in Tattoo Inks Harmful to Health? An Analytical Approach

Tattoo application is widely performed all over the world; however, injection of coloring substances into the skin as metals may pose a risk for allergies and other skin inflammations and systemic diseases. In this context, tattoo inks in green, black, and red colors of three brands were purchased. Before starting the analysis, the acid mixture suitable for microwave burning was determined, and according to these results, the inks were digested with nitric acid, hydrochloric acid, and hydrofluoric acid. Then, method validation was performed for tattoo inks using inductively coupled plasma-mass spectrometry. The relative contribution of metals to the tattoo ink composition was highly variable between colors and brands. Elements found in the main components of inks are as follows (in mg kg^-1): Al, 1191.1-3424.9; Co, 0.04-1.07; Cu, 1.24-2523.4; Fe, 16.98-318.42; Ni, 0.63-17.53; and Zn, 2.6-46.9. It has been determined by the Environmental Protection Agency that in some products, especially the copper element is above the determined limit. The analysis results obtained were classified by chemometric analysis, and the color and brand relationship were determined. More toxicological studies are necessary to understand the effects of tattoo inks containing heavy metals and/or organic components.

Tattoo inks are toxicological risks to human health: A systematic review of its ingredients, fate inside skin, toxicity due to polycyclic aromatic hydrocarbons, primary aromatic amines, metals, and overview of regulatory frameworks

Today, tattooing has become very popular among people all over the world. Tattooists, with the help of tiny needles, place tattoo ink inside the skin surface and unintentionally introduce a large number of unknown ingredients. These ingredients include polycyclic aromatic hydrocarbons (PAHs), heavy metals, and primary aromatic amines (PAAs), which are either unintentionally introduced along with the ink or produced inside the skin by different types of processes for example cleavage, metabolism and photodecomposition. These could pose toxicological risks to human health, if present beyond permissible limits. PAH such as Benzo(a)pyrene is present in carbon black ink. PAAs could be formed inside the skin as a result of reductive cleavage of organic azo dyes. They are reported to be highly carcinogenic by environmental protection agencies. Heavy metals, namely, cadmium, lead, mercury, antimony, beryllium, and arsenic are responsible for cancer, neurodegenerative diseases, cardiovascular, gastrointestinal, lungs, kidneys, liver, endocrine, and bone diseases. Mercury, cobalt sulphate, other soluble cobalt salts, and carbon black are in Group 2B, which means they may cause cancer in humans. Cadmium and compounds of cadmium, on the other hand, are in Group 1 (carcinogenic to humans). The present article addresses the various ingredients of tattoo inks, their metabolic fate inside human skin and unintentionally added impurities that could pose toxicological risk to human health. Public awareness and regulations that are warranted to be implemented globally for improving the safety of tattooing.

Current knowledge of the degradation products of tattoo pigments by sunlight, laser irradiation and metabolism: a systematic review

The popularity of tattooing has increased significantly over recent years. This has raised concerns about the safety of tattoo inks and their metabolites/degradation products. The photolytic and metabolic degradation of tattoo pigments may result in the formation of toxic compounds, with unforeseen health risks. A systematic literature review was undertaken to determine the current state of knowledge of tattoo pigments' degradation products when irradiated with sunlight, laser light or metabolised. The review demonstrates that there is a lack of knowledge regarding tattoo pigment degradation/metabolism, with only eleven articles found pertaining to the photolysis of tattoo pigments and two articles on the metabolism of tattoo pigments. The limited research indicates that the photolysis of tattoo pigments could result in many toxic degradation products, including hydrogen cyanide and carcinogenic aromatic amines.

Tattoo Pigment Identification in Inks and Skin Biopsies of Adverse Reactions by Complementary Elemental and Molecular Bioimaging with Mass Spectral Library Matching

Tattooing has become increasingly popular throughout society. Despite the recognized issue of adverse reactions in tattoos, regulations remain challenging with limited data available and a missing positive list. The diverse chemical properties of mostly insoluble inorganic and organic pigments pose an outstanding analytical challenge, which typically requires extensive sample preparation. Here, we present a multimodal bioimaging approach combining micro X-ray fluorescence (μXRF) and laser desorption ionization-mass spectrometry (LDI-MS) to detect the elemental and molecular composition in the same sample. The pigment structures directly absorb the laser energy, eliminating the need for matrix application. A computational data processing workflow clusters spatially resolved LDI-MS scans to merge redundant information into consensus spectra, which are then matched against new open mass spectral libraries of tattoo pigments. When applied to 13 tattoo inks and 68 skin samples from skin biopsies in adverse tattoo reactions, characteristic signal patterns of isotopes, ion adducts, and in-source fragments in LDI-MS¹ scans yielded confident compound annotations across various pigment classes. Combined with μXRF, pigment annotations were achieved for all skin samples with 14 unique structures and 2 inorganic pigments, emphasizing the applicability to larger studies. The tattoo-specific spectral libraries and further information are available on the tattoo-analysis.github.io website.

Histopathologic Spectrum of Findings Associated With Tattoos: Multicenter Study Series of 230 Cases

IMPORTANCE

Reactions to tattoo may simulate common dermatosis or skin neoplasms. Histopathology allows diagnosis and helps determining the level and degree of inflammation associated, consequently orientating treatment.

OBJECTIVE

To describe the histological features found in biopsies of cutaneous reactions to tattoo.

DESIGN

This study was designed as a multicenter case series.

SETTING

All consecutive histopathological samples of tattoos referred from 1992 to 2019 to the Hospital General de Catalunya, Hospital Germans Trias i Pujol, and a private practice, all in Barcelona, Spain, and from the Kempf und Pfaltz Histologische Diagnostik in Zurich, Switzerland were retrieved from the files.

PARTICIPANTS AND EXPOSURE

The inclusion criteria were all cosmetic/permanent makeup, artistic/professional, and traumatic tattoos associated with either inflammatory reactions alone and/or with tumors and/or infections. Exclusion criteria were cases without any associated pathologic finding in the place of the ink, amalgam tattoos, and medical or temporary tattoos.

MAIN OUTCOMES AND MEASURES

In all patients, clinical features (age, sex, location, tattoo color, and presentation) were recorded. Histological features evaluated included ink color, associated tumors or infections, and inflammatory reaction pattern. Inflammation was graded in low to moderate or severe.

RESULTS

From 477 biopsies diagnosed as tattoos, 230 cases from 226 patients met the inclusion criteria. Samples corresponded to 107 male and 120 female subjects and 3 of unknown gender. Median age was 39 years (ranging from 9 to 84 years). Fifty-three samples were referred from centers in Spain and 177 from the center in Switzerland. The series was analyzed in 2 parts: tattoos associated only with inflammatory reactions (117/230) and tattoos associated with tumors or infections (113/230). The most common form of inflammatory pattern associated with tattoo was the fibrosing reaction (79/117, 68%), followed by granulomatous reaction (56/117, 48%), lichenoid reaction (33/117, 28%), epithelial hyperplasia (28/117, 24%), pseudolymphoma (27/117, 23%) and spongiotic reaction (27/117, 23%). Combined features of 2 or more types of inflammatory patterns were seen in 64% cases.

CONCLUSIONS AND RELEVANCE

Our series confirms that cutaneous reactions to tattoos are polymorphous. Inflammation tends to present with combined patterns. Infections are tending to decline, and pathologic findings are not specific to ink color or clinical features.

Assessment of cytotoxicity and sensitization potential of intradermally injected tattoo inks in reconstructed human skin

Background

The number of people within the European population having at least one tattoo has increased notably, and with it the number of tattoo‐associated clinical complications. Despite this, safety information and testing regarding tattoo inks remain limited.

Objective

To assess cytotoxicity and sensitization potential of 16 tattoo inks after intradermal injection into reconstructed human skin (RHS).

Methods

Commercially available tattoo inks were injected intradermally into RHS (reconstructed epidermis on a fibroblast‐populated collagen hydrogel) using a permanent makeup device. RHS biopsies, tissue sections, and culture medium were assessed for cytotoxicity (thiazolyl blue tetrazolium bromide assay [MTT assay]), detrimental histological changes (haematoxylin and eosin staining), and the presence of inflammatory and sensitization cytokines (interleukin [IL]‐1α, IL‐8, IL‐18; enzyme‐linked immunosorbent assay).

Results

Varying degrees of reduced metabolic activity and histopathological cytotoxic effects were observed in RHS after ink injection. Five inks showed significantly reduced metabolic activity and enhanced sensitization potential compared with negative controls.

Discussion

Using the RHS model system, four tattoo inks were identified as highly cytotoxic and classified as potential sensitizers, suggesting that allergic contact dermatitis could emerge in individuals carrying these inks. These results indicate that an RHS‐based assessment of cytotoxicity and sensitization potential by intradermal tattoo ink injection is a useful analytical tool to determine ink‐induced deleterious effects.

Colored Tattoo Ink Screening Method with Optical Tissue Phantoms and Raman Spectroscopy

Due to the increasing popularity of tattoos among the general population, to ensure their safety and quality, there is a need to develop reliable and rapid methods for the analysis of the composition of tattoo inks, both in the ink itself and in already existing tattoos. This paper presents the possibility of using Raman spectroscopy to examine tattoo inks in biological materials. We have developed optical tissue phantoms mimicking the optical scattering coefficient typical for human dermis as a substitute for an in vivo study. The material employed herein allows for mimicking the tattoo-making procedure. We investigated the effect of the scattering coefficient of the matrix in which the ink is located, as well as its chemical compositions on the spectra. Raman surface line scanning has been carried out for each ink in the skin phantom to establish the spatial gradient of ink concentration distribution. This ensures the ability to detect miniature concentrations for a tattoo margin assessment. An analysis and comparison of the spectra of the inks and the tattooed inks in the phantoms are presented. We recommend the utilization of Raman spectroscopy as a screening method to enforce the tattoo ink safety legislations as well as an early medical diagnostic screening tool.

Safety of Tattoos and Permanent Make up (PMU) Colorants

The art of tattooing is a popular decorative approach for body decoration and has a corrective value for the face. The tattooing procedure is characterized by placing exogenous pigments into the dermis with a number of needles. The process of creating traditional and cosmetic tattoos is the same. Colorants are deposited in the dermis by piercing the skin with needles of specific shape and thickness, which are moistened with the colorant. Colorants (pigments or dyes) most of the time include impurities which may cause adverse reactions. It is commonly known that tattoo inks remain in the skin for lifetime. It is also a fact that the chemicals that are used in permanent makeup (PMU) colorants may stay in the body for a long time so there is a significant long-term risk for harmful ingredients being placed in the body. Tattoo and PMU colorants contain various substances and their main ingredients and decomposition components may cause health risks and unwanted side effects to skin.

Tattoos - more than just colored skin? Searching for tattoo allergens

During tattooing, a high amount of ink is injected into the skin. Tattoo inks contain numerous substances such as the coloring pigments, impurities, solvents, emulsifiers, and preservatives. Black amorphous carbon particles (carbon black), white titanium dioxide, azo or polycyclic pigments create all varieties of color shades in the visible spectrum. Some ingredients of tattoo inks might be hazardous and allergenic chemicals of unknown potential. In Germany, about 20 % of the general population is tattooed and related adverse reactions are increasingly reported. Since tattoo needles inevitably harm the skin, microorganisms can enter the wound and may cause infections. Non-allergic inflammatory reactions (for example cutaneous granuloma and pseudolymphoma) as well as allergic reactions may emerge during or after wound healing. Especially with allergies occurring after weeks, months or years, it remains difficult to identify the specific ingredient(s) that trigger the reaction. This review summarizes possible adverse effects related to tattooing with a focus on the development of tattoo-mediated allergies. To date, relevant allergens were only identified in rare cases. Here we present established methods and discuss current experimental approaches to identify culprit allergens in tattoo inks - via testing of the patient and in vitro approaches.

Formaldehyde Release From Predispersed Tattoo Inks: Analysis Using the Chromotropic Acid Method

BACKGROUND

Allergic contact dermatitis to tattoo ink may last from weeks to years. Formaldehyde is a strong sensitizer that may be present in predispersed tattoo inks.

OBJECTIVES

The aim of this study was to evaluate the presence of formaldehyde in predispersed tattoo inks using the chromotropic acid method.

METHODS

Tattoo inks from 39 companies were evaluated. Inclusion criteria included availability to purchase inks online through US tattoo product wholesalers or individual Web sites. Brands were grouped based on prevalence of use: common, uncommon, or rare. For common brands, 8 colors (primary colors, secondary colors, black, and white) were purchased. For uncommon and rare brands, 5 colors (primary colors, black, and white) were purchased. Each ink was tested with standard chromotropic acid method procedures; concentration of formaldehyde released was quantified using spectrophotometry.

RESULTS

In total, 127 tattoo inks were purchased and tested. Ninety-three (73%) tested positive for formaldehyde release; 34 (27%) tested negative. Formaldehyde release did not correlate with color or brand. At least 1 ink from all brands (except 1) was positive for formaldehyde release.

CONCLUSION

Approximately three-quarters of selected US tattoo inks tested positive for formaldehyde release. Clinicians should be aware of tattoo ink as a potential source of formaldehyde.

Solar Freckles: Long-Term Photochromic Tattoos for Intradermal Ultraviolet Radiometry

While tattooable nanotechnology for in-skin sensing and communication has been a popular concept in science fiction since the 1990s, the first tattooable intradermal nanosensors have only emerged in the past few years, and none have been demonstrated in human skin. We developed a photochromic tattoo that serves as an intradermal ultraviolet (UV) radiometer that provides naked-eye feedback about UV exposure in real time. These small tattoos, or "solar freckles", comprise dermally implanted colorimetric UV sensors in the form of nanoencapsulated leuco dyes that become more blue in color with increasing UV irradiance. We demonstrate the tattoos' functionality for both quantitative and naked-eye UV sensing in porcine skin ex vivo, as well as in human skin in vivo. Solar freckles offer an alternative and complementary approach to self-monitoring UV exposure for the sake of skin cancer prevention. Activated solar freckles provide a visual reminder to protect the skin, and their color disappears rapidly upon removal of UV exposure or application of topical sunscreen. The sensors are implanted in a minimally invasive procedure that lasts only a few seconds, yet remain functional for months to years. These semipermanent tattoos provide an early proof-of-concept for long-term intradermal sensing nanomaterials that provide users with biomedically relevant information in the form of an observable color change.

Study of Tattoo Colorants in Skin by Conventional and Polarized Light Microscopy

Tattoos are a common practice in the 21st century. Although most modern pigments are organic and made of vegetable or plastic compounds, they still sometimes elicit an adverse reaction in the skin. Identifying the tattoo pigment in such biopsies is not always an easy task. To study how tattoo inks appear in the skin, we injected 14 different colors of commercial tattoo ink into normal skin obtained from a mastectomy specimen. One unstained section was obtained from each case, as well as one section stained with hematoxylin-eosin from each case. All sections were observed under the microscope. Stained and unstained sections were also examined under polarized light. We did not observe any modification of the ink color with the staining process with hematoxylin-eosin. However, some pigments appeared differently in stained and unstained sections than in the vial. Pink was the most difficult color to identify from the eosinophilic tissue. None of the colors showed any birefringent particles. However, in some unstained slides under polarized light, the color of the pigment appeared more similar to the one in the vial than in the stained slide.

Tattoo-Associated Basal Cell Carcinoma: Coincident or Coincidence

Tattoos may be associated with medical complications including, albeit rarely, skin cancer. The features of a 46-year-old man who developed a basal cell carcinoma within a tattoo on his left scapula are described and the characteristics of the other 13 patients (7 men and 6 women) with tattoo-associated basal cell carcinoma are reviewed. The tumor usually occurs on the sun-exposed skin of individuals aged 60 years and older whose tattoo has often been present for 20 years or more. The pathogenesis of a basal cell carcinoma developing within a tattoo may merely be a coincidence. However, there is supporting evidence that the tattoo and the subsequent basal cell carcinoma may be coincident events whereby either tattoo injection-associated trauma or the tattoo pigments and dyes (in their native state or after ultraviolet radiation alteration) or both have a carcinogenic impact on the development of the basal cell carcinoma at that location.

Chemical hazard of tattoo colorants

Tattooing entails a high amount of tattoo colorants that is injected into skin. Tattoo colorants usually contain various substances of which the colouring component is the major ingredient that can be assigned to two different groups. Firstly, amorphous carbon particles (carbon black) are almost exclusively found in black tattoos. Secondly, tattooists use azo and polycyclic pigments to create nearly all colours of the visible spectrum. Due to their different but frequently complex chemistry, tattoo colorants usually contain various compounds like by-products and impurities which may exhibit health concerns. Professional tattooists inject that mixture into skin using the solid needles of tattoo machines. It is known that part of injected tattoo colorants is predominantly transported away from skin via lymphatic system. In addition to tattooing, exposure of tattooed skin to solar radiation or laser light may cause decomposition of pigment molecules leading to new and potential hazard chemical compounds. In light of the various hazard substances in the tattoo colorants and its decomposition products, tattooing might pose a health risk not only to skin but also to other organs of humans.

TatS: a novel in vitro tattooed human skin model for improved pigment toxicology research

Reports of tattoo-associated risks boosted the interest in tattoo pigment toxicity over the last decades. Nonetheless, the influence of tattoo pigments on skin homeostasis remains largely unknown. In vitro systems are not available to investigate the interactions between pigments and skin. Here, we established TatS, a reconstructed human full-thickness skin model with tattoo pigments incorporated into the dermis. We mixed the most frequently used tattoo pigments carbon black (0.02 mg/ml) and titanium dioxide (TiO2, 0.4 mg/ml) as well as the organic diazo compound Pigment Orange 13 (0.2 mg/ml) into the dermis. Tissue viability, morphology as well as cytokine release were used to characterize TatS. Effects of tattoo pigments were compared to monolayer cultures of human fibroblasts. The tissue architecture of TatS was comparable to native human skin. The epidermal layer was fully differentiated and the keratinocytes expressed occludin, filaggrin and e-cadherin. Staining of collagen IV confirmed the formation of the basement membrane. Tenascin C was expressed in the dermal layer of fibroblasts. Although transmission electron microscopy revealed the uptake of the tattoo pigments into fibroblasts, neither viability nor cytokine secretion was altered in TatS. In contrast, TiO2 significantly decreased cell viability and increased interleukin-8 release in fibroblast monolayers. In conclusion, TatS emulates healed tattooed human skin and underlines the advantages of 3D systems over traditional 2D cell culture in tattoo pigment research. TatS is the first skin model that enables to test the effects of pigments in the dermis upon tattooing.

Permanent tattooing has no impact on local sweat rate, sweat sodium concentration and skin temperature or prediction of whole-body sweat sodium concentration during moderate-intensity cycling in a warm environment

PURPOSES

This study investigated the impact of permanently tattooed skin on local sweat rate, sweat sodium concentration and skin temperature and determined whether tattoos alter the relationship between local and whole-body sweat sodium concentration.

METHODS

Thirteen tattooed men (27 ± 6 years) completed a 1 h (66 ± 4% of [Formula: see text]) cycling trial at 32 °C, 35% relative humidity. Sweat rate and sweat sodium concentration were measured using the whole-body washdown and local absorbent patch techniques. Patches and skin-temperature probes were applied over the right/left thighs and tattooed/non-tattooed (contralateral) regions.

RESULTS

Local sweat rates did not differ (p > 0.05) between the right (1.11 ± 0.38) and left (1.21 ± 0.37) thighs and the permanently tattooed (1.93 ± 0.82) and non-tattooed (1.72 ± 0.81 mg cm^-2 min^-1) regions. There were no differences in local sweat sodium concentration between the right (58.2 ± 19.4) and left (55.4 ± 20.3) thighs and the permanently tattooed (73.0 ± 22.9) and non-tattooed (70.2 ± 18.9 mmol L^-1) regions. Difference in local skin temperature between the right and left thighs (- 0.043) was similar to that between the permanently tattooed and non-tattooed (- 0.023 °C) regions. Prediction of whole-body sweat sodium concentration for the permanently tattooed (41.0 ± 6.7) and the non-tattooed (40.2 ± 5.3 mmol L^-1) regions did not differ.

CONCLUSION

Permanent tattoos do not alter local sweat rate, sweat sodium concentration or local skin temperature during moderate-intensity cycling exercise in a warm environment. Results from a patch placed over a tattooed surface correctly predicts whole-body sweat sodium concentration from an equation developed from a non-tattooed region.

Safety of tattoos and permanent make-up: a regulatory view

The continuous increase in the popularity of tattoos and permanent make-up (PMU) has led to substantial changes in their societal perception. Besides a better understanding of pathological conditions associated with the injection of highly diverse substances into subepidermal layers of the skin, their regulation has occupied regulatory bodies around the globe. In that sense, current regulatory progress in the European Union is an exemplary initiative for improving the safety of tattooing. On one hand, the compilation of market surveillance data has provided knowledge on hazardous substances present in tattoo inks. On the other hand, clinical data gathered from patients enabled correlation of adverse reactions with certain substances. Nevertheless, the assessment of risks remains a challenge due to knowledge gaps on the biokinetics of highly complex inks and their degradation products. This review article examines the strategies for regulating substances in tattoo inks and PMU in light of their potential future restriction in the frame of the REACH regulation. Substance categories are discussed in terms of their risk assessment and proposed concentration limits.

Basal Cell Carcinoma Originating in a Tattoo: Case Report and Review of an Uncommon Complication in Tattoo Recipients

Background

The placement of a tattoo is a common event. Basal cell carcinoma arising from a tattoo is rare despite this neoplasm being the most common form of skin cancer.

Objective

We describe a 41-year-old man who developed a basal cell carcinoma in his tattoo and review the literature of basal cell carcinomas originating in a tattoo.

Methods

A literature search using PubMed was performed. The following terms were searched: "basal," "carcinoma," "cell," and "tattoo." The characteristics of individuals with a basal cell carcinoma originating in a tattoo were analyzed and summarized.

Results

A total of 13 patients (6 women and 7 men) with a basal cell carcinoma arising in a tattoo have been reported. The majority of the tumors were located on the head (6 cases, 46.2%) followed by either an upper extremity (4 cases, 30.7%) or the trunk (3 cases, 23.1%). Most of the carcinomas were asymptomatic; however, 2 patients reported pruritus associated with their tumor. Nodular basal cell carcinoma was the most common subtype diagnosed (5 tumors), followed by superficial basal cell carcinoma (2 tumors). One patient had either a pagetoid or a mixed (nodular and sclerosing) histology. The pathological variant was not described for 4 patients.

Conclusions

Basal cell carcinoma arising in a tattoo is a rare occurrence. Although this occurrence may be coincidental, emerging evidence of carcinogenesis associated with tattoo pigment may suggest a causal link. Elucidating this important relationship warrants further investigation.

Tattoo inks: Characterization and in vivo and in vitro toxicological evaluation

Tattoo inks represent a growing market in the world economy, but this growth is associated with an increase in reports of adverse effects caused by the use of this product. In this study, four commercial tattoo inks (blue, green, red and black) were studied to characterize the composition and particle size and identify possible in vivo and in vitro toxicological effects on Daphnia magna and HaCaT cells, respectively. Compositional analysis confirmed the functional groups in the vehicles and organic pigments. The presence of nanoparticles was confirmed by image analysis. The toxicological evaluation indicated distinct results for blue and green inks for the parameters tested, despite the presence of similar levels of metals. The red ink, followed by the green, presented the highest toxicity, which may be related to pigments containing azo compounds and not to the metal fraction. Black ink was found to be the safest toxicologically. This paper provides an overview of the composition of tattoo inks and their toxicological effects in epidermal cells and in the environment.

Laser assisted tattoo removal – state of the art and new developments

Decorative tattoos including permanent make-up are very popular world-wide. As the trend for tattoo acquisition increases, the demand for tattoo removal will similarly rise. This article highlights the state of the art and new developments in laser assisted tattoo removal.

Confocal Raman microscopy combined with optical clearing for identification of inks in multicolored tattooed skin in vivo

Raman measurements applied on freshly tattooed porcine skin ex vivo showed a possibility of obtaining the ink pigment related information in the skin. Based on these results, confocal Raman microscopy was used to identify the tattoo ink pigments of different colors in multicolored tattooed human skin in vivo. The Raman signatures of tattoo ink pigments were unique. Therefore, it could be shown that the applied method is successful for the identification of the tattoo ink pigments in human skin in vivo down to depths of approx. 50 μm, which is sufficient to screen the entire epidermis and the top of the papillary dermis area on the forearm and leg skin sites. Additional application of the optical clearing technique in vivo by topical application of glycerol, combined with tape stripping removal of the uppermost stratum corneum layers and defatting allows the extension of depths of investigation in tattooed skin down to approx. 400 μm, i.e. to cover the entire papillary dermis and a large part of the reticular dermis. Thus, the tattoo ink pigments were identified in vivo and depth-dependently in human tattooed skin confirming their presence in the papillary and reticular dermis. The proposed non-invasive in vivo Raman screening combined with optical clearing for identifying the tattoo pigments in the dermis can be an important task preceding a laser-based tattoo removal procedure and for determining the optimal laser parameters.

Allergic reactions in red tattoos: Raman spectroscopy for 'fingerprint' detection of chemical risk spectra in tattooed skin and culprit tattoo inks

AIM

The aim of this study was to assess the feasibility of Raman spectroscopy as a screening technique for chemical characterisation of tattoo pigments in pathologic reacting tattoos and tattoo ink stock products to depict unsafe pigments and metabolites of pigments.

MATERIALS/METHODS

Twelve dermatome shave biopsies from allergic reactions in red tattoos were analysed with Raman spectroscopy (A 785-nm 300 mW diode laser). These were referenced to samples of 10 different standard tattoo ink stock products, three of these identified as the culprit inks used by the tattooist and thus by history the source of the allergy. Three primary aromatic amine (PAA) laboratory standards (aniline, o-anisidine and 3,3'-dichlorobenzidine) were also studied.

RESULTS

Application of Raman spectroscopy to the shave biopsies was technically feasible. In addition, all ten inks and the three PAA standards could be discriminated. 10/12 shave biopsies provided clear fingerprint Raman signals which differed significantly from background skin, and Raman spectra from 8/12 biopsies perfectly matched spectra from the three culprit ink products. The spectrum of one red ink (a low cost product named 'Tattoo', claimed to originate from Taiwan, no other info on label) was identified in 5/12 biopsies. Strong indications of the inks 'Bright Red' and 'Crimson Red' were seen in three biopsies. The three PAA's could not be unambiguously identified.

CONCLUSION

This study, although on a small-scale, demonstrated Raman spectroscopy to be feasible for chemical analysis of red pigments in allergic reactions. Raman spectroscopy has a major potential for fingerprint screening of problematic tattoo pigments in situ in skin, ex vivo in skin biopsies and in tattoo ink stock products, thus, to eliminate unsafe ink products from markets.

Patterns of Reactions to Red Pigment Tattoo and Treatment Methods

Tattoos are common and used extensively as either body art or cosmetic make-up; more rarely, they can be traumatic in nature. We have systemically analysed the literature for the patterns of red pigment tattoo reactions and their treatment options. Our search identified 18 articles; there was 1 non-randomised controlled trial, and the rest were small case studies. In total 139 patients were included within the studies. This review systematically analyses the different subsets of red tattoo reactions including lichenoid, dermatitis, granulomatous, pseudolymphomatous and miscellaneous reactions. The current evidence for the treatment for the above is presented. Dermatitis and lichenoid reactions appear to be the most common subtype of red pigment reactions with various treatment methods applied showing laser intervention to have some degree of success.

A medical-toxicological view of tattooing

Long perceived as a form of exotic self-expression in some social fringe groups, tattoos have left their maverick image behind and become mainstream, particularly for young people. Historically, tattoo-related health and safety regulations have focused on rules of hygiene and prevention of infections. Meanwhile, the increasing popularity of tattooing has led to the development of many new colours, allowing tattoos to be more spectacular than ever before. However, little is known about the toxicological risks of the ingredients used. For risk assessment, safe intradermal application of these pigments needs data for toxicity and biokinetics and increased knowledge about the removal of tattoos. Other concerns are the potential for phototoxicity, substance migration, and the possible metabolic conversion of tattoo ink ingredients into toxic substances. Similar considerations apply to cleavage products that are formed during laser-assisted tattoo removal. In this Review, we summarise the issues of concern, putting them into context, and provide perspectives for the assessment of the acute and chronic health effects associated with tattooing.

Bioanalytical evidence that chemicals in tattoo ink can induce adaptive stress responses

Tattooing is becoming increasingly popular, particularly amongst young people. However, tattoo inks contain a complex mixture of chemical impurities that may pose a long-term risk for human health. As a first step towards the risk assessment of these complex mixtures we propose to assess the toxicological hazard potential of tattoo ink chemicals with cell-based bioassays. Targeted modes of toxic action and cellular endpoints included cytotoxicity, genotoxicity and adaptive stress response pathways. The studied tattoo inks, which were extracted with hexane as a proxy for the bioavailable fraction, caused effects in all bioassays, with the red and yellow tattoo inks having the greatest response, particularly inducing genotoxicity and oxidative stress response endpoints. Chemical analysis revealed the presence of polycyclic aromatic hydrocarbons in the tested black tattoo ink at concentrations twice the recommended level. The detected polycyclic aromatic hydrocarbons only explained 0.06% of the oxidative stress response of the black tattoo ink, thus the majority of the effect was caused by unidentified components. The study indicates that currently available tattoo inks contain components that induce adaptive stress response pathways, but to evaluate the risk to human health further work is required to understand the toxicokinetics of tattoo ink chemicals in the body.