Tattooing of skin results in transportation and light-induced decomposition of tattoo pigments – a first quantification in vivo using a mouse model

Esthetic and medical tattooing: Part I: Tattooing techniques, implications, and adverse effects in healthy populations and special groups

Tattooing, the introduction of exogenous pigments into the skin, has a rich history spanning thousands of years, with cultural, cosmetic, and medical significance. With the increasing prevalence of tattoos, understanding their potential complications and contraindications is of growing importance. The most common complications are hypersensitivity reactions, which may vary in morphology and timing. Infectious complications are often due to inadequate aseptic and hygienic practices during the tattooing process or healing period. Tattoo pigment can present diagnostic challenges, affecting cancer diagnosis and imaging. This CME article explores the history, cultural significance, epidemiology, chemistry, technique, contraindications, and complications of tattoos. Appreciating these factors can help individuals considering tattoos understand the safety and potential risks of their body art, and provide physicians with a thorough understanding of tattooing if consulted.

Tattoos: risks and complications, clinical and histopathological approach

BACKGROUND

Skin modification through tattoos is as old as humanity itself. However, this trend is on the rise, and with the use of different types of pigments and application practices, both cutaneous and systemic complications can arise. Adverse reactions can be grouped into five classes: inflammatory, infectious, neoplastic, aesthetic, and miscellaneous. On histopathology, inflammatory reactions can exhibit a lichenoid pattern or present as spongiotic dermatitis, granulomatous reactions, pseudolymphoma, pseudoepitheliomatous hyperplasia, or scleroderma/morphea-like changes. This article reviews tattoo complications, including their clinical and histopathological characteristics.

METHODS

An open search was conducted on PubMed using the terms "tattoo", "complications", and "skin". No limits were set for period, language, or publication type of the articles.

RESULTS

Reactions to tattoos are reported in up to 67% of people who get tattooed, with papulonodular and granulomatous reactions being the most common. Some neoplastic complications have been described, but their causality is still debated. Any pigment can cause adverse reactions, although red ink is more frequently associated with them. Patients with pre-existing dermatoses may experience exacerbation or complications of their diseases when getting tattoos; therefore, this procedure is not recommended for this patient group.

CONCLUSIONS

Dermatological consultation is recommended before getting a tattoo, as well as a histopathological examination in case of complications. In patients who develop cutaneous inflammatory reactions following tattooing, additional studies are recommended to investigate systemic diseases such as sarcoidosis, pyoderma gangrenosum, atopic dermatitis, and neoplasms. It is important for physicians to be trained in providing appropriate care in case of complications.

Tattoos as a risk factor for malignant lymphoma: a population-based case-control study

Background

The popularity of tattoos has increased dramatically over the last few decades. Tattoo ink often contains carcinogenic chemicals, e.g., primary aromatic amines, polycyclic aromatic hydrocarbons, and metals. The tattooing process invokes an immunologic response that causes translocation of tattoo ink from the injection site. Deposition of tattoo pigment in lymph nodes has been confirmed but the long-term health effects remain unexplored. We used Swedish National Authority Registers with full population coverage to investigate the association between tattoo exposure and overall malignant lymphoma as well as lymphoma subtypes.

Methods

We performed a case-control study where we identified all incident cases of malignant lymphoma diagnosed between 2007 and 2017 in individuals aged 20-60 years in the Swedish National Cancer Register. Three random age- and sex-matched controls per case were sampled from the Total Population Register using incidence density sampling. We assessed exposure through a questionnaire in 2021, and data on potential confounders were retrieved from registers. We used multivariable logistic regression to estimate the incidence rate ratio (IRR) of malignant lymphoma in tattooed individuals.

Findings

The study population consisted of 11,905 individuals, and the response rate was 54% among cases (n = 1398) and 47% among controls (n = 4193). The tattoo prevalence was 21% among cases and 18% among controls. Tattooed individuals had a higher adjusted risk of overall lymphoma (IRR = 1.21; 95% CI 0.99-1.48). The risk of lymphoma was highest in individuals with less than two years between their first tattoo and the index year (IRR = 1.81; 95% CI 1.03-3.20). The risk decreased with intermediate exposure duration (three to ten years) but increased again in individuals who received their first tattoo ≥11 years before the index year (IRR = 1.19; 95% CI 0.94-1.50). We found no evidence of increasing risk with a larger area of total tattooed body surface. The risk associated with tattoo exposure seemed to be highest for diffuse large B-cell lymphoma (IRR 1.30; 95% CI 0.99-1.71) and follicular lymphoma (IRR 1.29; 95% CI 0.92-1.82).

Interpretation

Our findings suggested that tattoo exposure was associated with an increased risk of malignant lymphoma. More epidemiologic research is urgently needed to establish causality.

Funding

The Swedish Research Council for Health, Working Life and Welfare.

What's in My Ink: An Analysis of Commercial Tattoo Ink on the US Market

As tattoos continue to rise in popularity, the demand for tattoo ink has surged. Historically, tattoo inks have been underregulated in the US market. This study analyzes inks from nine different brands that are common in the United States, ranging from major to small manufacturers. Out of 54 inks, 45 contained unlisted additives and/or pigments. Major, unlisted adulterants include poly(ethylene glycol), propylene glycol, and higher alkanes. Many of the adulterants pose possible allergic or other health risks. Taken together, the results from this study highlight the potential for a significant issue around inaccurate tattoo ink labeling in the United States.

Types of colourants used in tattoo and permanent make-up techniques, legal regulations, health, and psychological aspects of tattooing

Background

It is estimated that more than 60 million people in Europe, that is, around 12% of the European population, have at least one tattoo. However, there is still little information on the long-term effects of tattoos. Inks used for tattooing are a mixture of chemicals, with pigments being the main components responsible for the visual effect. The pigments used are not produced specifically as ingredients for tattooing, but mainly/primarily for the needs of industry, where lower purity requirements and quality standards are acceptable. It is therefore necessary to understand the risks associated with tattoos, but also to implement appropriate legal regulations. The aim of this article was to collect and summarise the results of research conducted so far on the type of colourants used in tattoo ink and to analyze the impact of these on human health. In addition, as part of this work, the current legal acts regulating the concentration limits and composition of inks used in tattooing as well as the psychological aspects of tattooing were collected and presented.

Methods

Scientific reports and articles from renowned journals from 1994 to 2022, relevant review and research publications in PubMed, and Google Scholar were analyzed. To analyze the available research literature, the Web of Science, Scopus, PubMed databases were used. The following keywords were used to search for publications: tattoos, colourants used in tattoos, side effects of tattoos, legal acts, psychological aspects of tattoos.

Results

The result of the literature analysis indicates a risk to health and side effects associated with tattooing the body. There are still no standardised test methods to analyze tattoo inks and assess their safety. Although the art of tattooing has been known for millennia, European legal authorities have not yet implemented effective regulations. Currently, tattoo products in Europe are covered by the general REACH regulation (Resolution ResAP, 2008; EU regulation 2020/2081, 2020). on product safety. The new amendment in force since January 4, 2022 introduces concentration limits for certain substances used in tattoo and permanent makeup inks. However, these provisions do not sufficiently protect either the consumer or the tattoo industry.

Conclusions

The results of the research indicate a potentially harmful effect on skin health. A more stringent safety assessment of the colourants used for tattooing is recommended, supported by studies and applicable legislation.

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.

Hypersensitivity to permanent tattoos: Literature summary and comprehensive review of patch tested tattoo patients 1997-2022

We outline constituents of tattoo and permanent make-up ink with regard to inflammatory tattoo reactions and population-based confounders. The comprehensive review of patch-tested tattoo patients between 1997 and 2022 shows that tattoo allergy cannot be reliably diagnosed via patch testing with today's knowledge. Weak penetration and slow haptenization of pigments, unavailability of pigments as test allergens and a lack of knowledge concerning relevant epitopes hamper the diagnosis of tattoo allergy. Patch testing p-phenylenediamine and disperse (textile) dyes is not able to close this gap. Sensitization to metals was associated with all types of tattoo complications, although often not clinically relevant for the tattoo reaction. Binders and industrial biocides are frequently missing on ink declarations and should be patch tested. The pigment carbon black (C.I. 77266) is no skin sensitizer. Patch tests with culprit inks were usually positive with cheap ink products for non-professional use or with professionally used inks in patients with eczematous reactions characterized by papules and infiltration. Tape stripping before patch testing and patch test readings on Day 8 or 10 may improve the diagnostic quality. The meaningfulness of the categorical EU-wide ban of Pigment Green 7 and Pigment Blue 15:3 is not substantiated by the presented data.

Immediate and Sustained Effects of Cobalt and Zinc-Containing Pigments on Macrophages

Pigments are among the oldest nanoparticulate products known to mankind, and their use in tattoos is also very old. Nowadays, 25% of American people aged 18 to 50 are tattooed, which poses the question of the delayed effects of tattoos. In this article, we investigated three cobalt [Pigment Violet 14 (purple color)] or cobalt alloy pigments [Pigment Blue 28 (blue color), Pigment Green 14 (green color)], and one zinc pigment [Pigment White 4 (white color)] which constitute a wide range of colors found in tattoos. These pigments contain microparticles and a significant proportion of submicroparticles or nanoparticles (in either aggregate or free form). Because of the key role of macrophages in the scavenging of particulate materials, we tested the effects of cobalt- and zinc-based pigments on the J774A.1 macrophage cell line. In order to detect delayed effects, we compared two exposure schemes: acute exposure for 24 hours and an exposure for 24 hours followed by a 3-day post-exposure recovery period. The conjunction of these two schemes allowed for the investigation of the delayed or sustained effects of pigments. All pigments induced functional effects on macrophages, most of which were pigment-dependent. For example, Pigment Green 19, Pigment Blue 28, and Pigment White 4 showed a delayed alteration of the phagocytic capacity of cells. Moreover, all the pigments tested induced a slight but significant increase in tumor necrosis factor secretion. This effect, however, was transitory. Conversely, only Pigment Blue 28 induced both a short and sustained increase in interleukin 6 secretion. Results showed that in response to bacterial stimuli (LPS), the secretion of tumor necrosis factor and interleukin 6 declined after exposure to pigments followed by a recovery period. For chemoattractant cytokines (MCP-1 or MIP-1α), delayed effects were observed with a secretion decreased in presence of Pigment Blue 28 and Pigment violet 14, both with or without LPS stimuli. The pigments also induced persisting changes in some important macrophage membrane markers such as CD11b, an integrin contributing to cell adhesion and immunological tolerance. In conclusion, the pigments induced functional disorders in macrophages, which, in some cases, persist long after exposure, even at non-toxic doses.

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.

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.

Glyceryl Tristearate-Based Lipid Microparticles Loaded with the Tattoo Colorant, Acid Red 87: Colorant Retention Capacity in Excised Porcine Skin

BACKGROUND

With the increasing diffusion of tattooing, the photolability of tattoo inks has become a critical issue, as available data indicated that several tattoo colorants are unstable under sunlight, generating potentially toxic photodegradation products. Therefore, it is desirable to enhance the photostability of coloring agents contained in tattoo inks.

AIMS

Lipid microparticles (LMs) highly loaded with Acid Red 87 (C.I. 45380), a colorant used in tattoo inks, were evaluated for their effect on the colorant photoinstability. In addition, the capacity of the LMs to retain the incorporated C.I. 45380 colorant after their intradermal administration in excised porcine skin was investigated.

METHODS

LMs loaded with C.I. 45380 were prepared using glyceryl tristearate as the lipidic material and phosphatidylcholine as the surfactant. Non-encapsulated C.I. 45380 or the colorant-loaded LMs were irradiated with a solar simulator for photodecomposition studies or introduced in the excised porcine skin mounted in Franz diffusion cells for stability evaluation in the dermal tissue.

RESULTS AND CONCLUSION

The colorant content of the microparticles was 17.7%, and their size ranged from 25 to 170 μm. The light-induced degradation of C.I. 45380 was significantly decreased by its incorporation in the LMs from 20.2 ± 5.8% to 1.9 ± 2.1%. Moreover, after intradermal injection of free or microencapsulated C.I. 45380 in the excised pig skin, the LMs reduced by 93.7% (from 24.6 to 1.5%) the quantity of the colorant diffused and hence lost in the Franz cell receptor fluid. Hence, the LM carrier efficiently retained the entrapped C.I. 45380 following incubation in the dermal region of the isolated porcine skin, which is in favor of a long-lasting tattoo. Based on these data, the incorporation of C.I. 45380 in the LMs could represent a potentially useful strategy to reduce the photodecomposition of the tattoo colorant and its harmful interactions with the skin tissue.

High-frequency (20 MHz) high-intensity focused ultrasound: New ablative method for color-independent tattoo removal in 1-3 sessions. An open-label exploratory study

BACKGROUND

High-intensity focused ultrasound (HIFU) operating at 20 MHz is new and potentially applicable to ablative tattoo removal. The method was documented safe and rational in preclinical testing.

MATERIALS AND METHODS

High-intensity focused ultrasound was introduced to subjects when lasers and dermatome shaving had failed or caused side effects. Transducers with focal depths between 1.1 mm and 1.7 mm in the skin were used, and settings of 0.4-1.2 J/shot at pulse durations of 150 ms were applied. Tattoos were covered with synergistic "shoulder-by-shoulder" focused ultrasound shots. Effectiveness and side effects were measured.

RESULTS

Twenty-two subjects with 67 tattoos were treated. 62% benefitted (19% cleared, 43% partially cleared), and 28% had minor effect. VAS pain was 5-6 versus 7-9 with previous lasers removal. Wound healing was longer after HIFU ablation (1-3 months). 57% of subjects had no scar or minor visible changes of skin surface markings only, while 19% had moderate or major skin thickening. Hypertrophic scar or keloid scars were not observed.

DISCUSSION/CONCLUSION

High-intensity focused ultrasound was effective in removal of difficult tattoos of any color where Nd:YAG lasers had failed. The method only needs 1-3 sessions. As an ablative method, the wound healing period is longer than with laser removal and needs attention. Focused ultrasound can be used as a first-line treatment of smaller tattoos independent of color, and second line when Nd:YAG lasers have failed or caused problems. The operator shall be qualified, as with lasers.

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.

Incorporation in Lipid Microparticles of Acid Red 87, a Colorant Used in Tattoo Inks: Effect on Photodegradation Under Simulated Sunlight and Laser Radiation

Tattoo colorants decompose under solar radiation and when exposed to laser light for their removal, leading to the accumulation in the dermis of toxic products. Aim of this study was to develop lipid microparticles (LMs) loaded with the colorant, Acid Red 87 (C.I. 45380) used in tattoo inks, and to investigate the effect of this system on the photostability of the colorant under simulated sunlight or laser irradiation. LMs loaded with C.I. 45380 were prepared by melt emulsification using tristearin and phosphatidylcholine as excipients. They were characterized by optical microscopy, laser diffraction, X-ray diffraction and release studies. Free C.I. 45380 and the colorant-loaded LMs were irradiated with a solar simulator or a Q-switched laser. Irradiation with a solar simulator demonstrated that photodecomposition of C.I. 45380 was markedly reduced by incorporation of the dye in the LMs, from 20.5 ± 4.6% to 1.3 ± 1.8%. Conversely, the laser-induced degradation of the colorant (30.1 ± 6.6%) was not significantly influenced by encapsulation in the LMs (the encapsulated C.I. 45380 loss was 27.4 ± 5.5%). Incorporation of C.I. 45380 in lipid microparticles enhances the photostability under sunlight of tattoo inks containing this colorant, without affecting its laser-induced degradation and hence laser removal efficiency.

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.

Identification of pigments related to allergic tattoo reactions in 104 human skin biopsies

Background

Red tattoos are prone to allergic reactions. The identity of the allergen(s) is mostly unknown.

Objectives

Chemical analysis of human skin biopsies from chronic allergic reactions in red tattoos to identify culprit pigment(s) and metals.

Material and methods

One hundred four dermatome biopsies were analyzed by matrix‐assisted laser desorption/ionization tandem mass spectrometry (MALDI‐MS/MS) for identification of commonly used organic pigments. Metal concentrations were assessed by inductively coupled plasma (ICP)‐MS and x‐ray fluorescence (XRF). Fourteen patients had cross‐reactions in other red tattoos.

Results

In total, the identified pigments were mainly azo Pigment Red (P.R.) 22 (35%), P.R. 210 (24%), P.R. 170 (12%), P.R. 5 (0.9%), P.R. 112 (0.9%), and Pigment Orange (P.O.) 13 (11%). P.R. 122 (0.9%) and Pigment Violet (P.V.) 23 (8%) were also common. P.R. 22, P.R. 170, and P.R. 210 also dominated in patients with cross‐reactions. In 22% of the biopsies, no red pigment was detected. Element analysis indicated the presence of the sensitizers nickel and chromium.

Conclusions

P.R. 22, P.R. 170, and P.R. 210 were identified as the prevailing pigments behind chronic allergic reactions in red tattoos. The epitope causing the reaction might be a pigment‐degradation product. Metal contamination may derive from different sources, and its role in red tattoo allergy cannot be ascertained.

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.

Distribution of nickel and chromium containing particles from tattoo needle wear in humans and its possible impact on allergic reactions

BACKGROUND

Allergic reactions to tattoos are amongst the most common side effects occurring with this permanent deposition of pigments into the dermal skin layer. The characterization of such pigments and their distribution has been investigated in recent decades. The health impact of tattoo equipment on the extensive number of people with inked skin has been the focus of neither research nor medical diagnostics. Although tattoo needles contain high amounts of sensitizing elements like nickel (Ni) and chromium (Cr), their influence on metal deposition in skin has never been investigated.

RESULTS

Here, we report the deposition of nano- and micrometer sized tattoo needle wear particles in human skin that translocate to lymph nodes. Usually tattoo needles contain nickel (6-8%) and chromium (15-20%) both of which prompt a high rate of sensitization in the general population. As verified in pig skin, wear significantly increased upon tattooing with the suspected abrasive titanium dioxide white when compared to carbon black pigment. Additionally, scanning electron microscopy of the tattoo needle revealed a high wear after tattooing with ink containing titanium dioxide. The investigation of a skin biopsy obtained from a nickel sensitized patient with type IV allergy toward a tattoo showed both wear particles and iron pigments contaminated with nickel.

CONCLUSION

Previously, the virtually inevitable nickel contamination of iron pigments was suspected to be responsible for nickel-driven tattoo allergies. The evidence from our study clearly points to an additional entry of nickel to both skin and lymph nodes originating from tattoo needle wear with an as yet to be assessed impact on tattoo allergy formation and systemic sensitization.

The safety of tattoo inks: Possible options for a common regulatory framework

Tattoo prevalence has been increasing in the last 25 years, but specific regulations on tattoo inks are still missing. In the European Union, no supranational regulation is available and only few national provisions cover them. In the United States, tattoo inks are classified as cosmetics but are not approved for injection into the dermis. Health risks for consumers may derive from microbiological contamination and the presence of toxic substances or nanomaterials. However, current regulations and non-binding recommendations, where present, only address the microbiological and chemical risks, completely overlooking nanotoxicity. The aim of this paper is to promote awareness of the risks associated with tattoo inks and the nanomaterials contained therein. In particular, the need for a harmonised regulation or, at least, a set of minimal requirements is highlighted to improve the safety of tattoo inks and market surveillance by regulatory authorities.

Synthetic nickel-containing superoxide dismutase attenuates para-phenylenediamine-induced bladder dysfunction in rats

Para (p)-phenylenediamine and its toxic metabolites induce excess reactive oxygen species formation that results in bladder voiding dysfunction. We determined the effects of synthetic Ni-containing superoxide dismutase mimics and the role of oxidative stress in p-phenylenediamine-induced urinary bladder dysfunction. P-phenylenediamine (60 μg/kg/day) was intraperitoneally administered for 4 weeks to induce bladder injury in female Wistar rats. Synthetic Ni-containing superoxide dismutase mimics, WCT003 (1.5 mg/kg) and WCT006 (1.5 mg/kg), were then intraperitoneally administered for 2 weeks. Transcystometrograms were performed in urethane-anesthetized rats. The in vitro and in vivo reactive oxygen species levels and pathological changes in formalin-fixed bladder sections were evaluated. Western blotting and immunohistochemistry elucidated the pathophysiological mechanisms of oxidative stress-induced apoptosis, autophagy, and pyroptosis. P-phenylenediamine increased voiding frequency, blood and urinary bladder levels of reactive oxygen species, and neutrophil and mast cell infiltration. It also upregulated biomarkers of autophagy (LC3 II), apoptosis (poly (ADP-ribose) polymerase), and pyroptosis (Caspase 1). WCT003 and WCT006 ameliorated reactive oxygen species production, inflammation, apoptosis, autophagy, pyroptosis, and bladder hyperactivity. P-phenylenediamine increased oxidative stress, inflammatory leukocytosis, autophagy, apoptosis, and pyroptosis formation within the urinary bladder. Novel synthetic nickel-containing superoxide dismutase mimics relieved p-phenylenediamine-induced bladder inflammation and voiding dysfunction.

Synchrotron-based ν-XRF mapping and μ-FTIR microscopy enable to look into the fate and effects of tattoo pigments in human skin

The increasing prevalence of tattoos provoked safety concerns with respect to particle distribution and effects inside the human body. We used skin and lymphatic tissues from human corpses to address local biokinetics by means of synchrotron X-ray fluorescence (XRF) techniques at both the micro (μ) and nano (ν) scale. Additional advanced mass spectrometry-based methodology enabled to demonstrate simultaneous transport of organic pigments, heavy metals and titanium dioxide from skin to regional lymph nodes. Among these compounds, organic pigments displayed the broadest size range with smallest species preferentially reaching the lymph nodes. Using synchrotron μ-FTIR analysis we were also able to detect ultrastructural changes of the tissue adjacent to tattoo particles through altered amide I α-helix to β-sheet protein ratios and elevated lipid contents. Altogether we report strong evidence for both migration and long-term deposition of toxic elements and tattoo pigments as well as for conformational alterations of biomolecules that likely contribute to cutaneous inflammation and other adversities upon tattooing.

Hepatic co-cultures in vitro reveal suitable to detect Nrf2-mediated oxidative stress responses on the bladder carcinogen o-anisidine

The azo dye o-anisidine is known as an industrial and environmental pollutant. Metabolites of o-anisidine remain in the liver for >24h. However, the toxicological impact of o-anisidine on the liver and its individual cell types, e.g., hepatocytes and immune cells, is currently poorly understood. A novel co-culture system, composed of HepG2 or Huh-7 cells, and differentiated THP-1 cells was used to study the metabolic capacity towards o-anisidine, and compared to primary murine hepatocytes which express high enzyme activities. As model compounds the carcinogenic arylamine o-anisidine and its non-carcinogenic isomer, p-anisidine, as well as caffeine were used. Global proteome analysis revealed an activation of eIF2 and Nrf2-mediated oxidative stress response pathways only in co-cultures after treatment with o-anisidine. This was confirmed via detection of reactive oxygen species. In addition, the mitochondrial membrane potential decreased already after 3h treatment of cells, which correlated with a decrease of ATP levels (R²>0.92). In the supernatant of co-cultured, but not single-cultured HepG2 and Huh-7 cells, o-anisidine caused increases of damage-associated proteins, such as HMGB1 (high mobility group box-1) protein. In summary, only co-cultures of HepG2 and THP-1 cells predict o-anisidine induced stress responsive pathways, since the system has a higher sensitivity compared to single cultured cells.

Socio-epidemiologic aspects and cutaneous side effects of permanent tattoos in Germany - Tattoos are not restricted to a specific social phenotype

Background: More and more people of all age classes have a tattoo. Intriguingly, there are multiple prejudices in the general population and published data that concern tattooed persons, such as being criminals, having a low education, being alcohol or drug abusers, or more risky in their life style. Objective: To obtain and to evaluate sociodemographic data on tattooed persons, to investigate the incidence of tattoo-related cutaneous complications and to define personal risk factors and course of the persons after being tattooed concerning behavior of personal environment. Patients and Methods: We interviewed 426 participants with already existing tattoos and 20 participants just before getting a new tattoo by using an online questionnaire. The participators were asked about socio-epidemiologic aspects of tattoos in general and special aspects of their own tattoo(s) in particular. There were no exclusion criteria. Results: Tattoos are interesting for people seeking popular body art, esp. university graduates and financially-secure individuals. 446 persons participated in this study. Most of the persons were female with a mean age of 35. Local pruritus around the tattooed area was the most common cutaneous side effect among the participants. 93.5% of the participants did not want a tattoo removal. Intriguingly, most of the participants experienced no career problems related to the tattoo(s). Limitations: The study population is not representative as we included only persons being tattooed prior to or getting newly tattooed. Furthermore, there is a potential selection bias as the participation in this study was voluntary. Only persons that felt involved by the flyer did answer the questionnaire. Conclusion: The present data shows that common tattooed persons are not low educated criminals with any drug or alcohol abuse or with risky life style. Nowadays being tattooed encompasses a kind of body art and displays a certain kind of lifestyle habit.

Identification and hazard prediction of tattoo pigments by means of pyrolysis-gas chromatography/mass spectrometry

The implementation of regulation for tattoo ink ingredients across Europe has generated the need for analytical methods suitable to identify prohibited compounds. Common challenges of this subject are the poor solubility and the lack of volatility for most pigments and polymers applied in tattoo inks. Here, we present pyrolysis coupled to online gas chromatography and electron impact ionization mass spectrometry (py-GC/MS) as quick and reliable tool for pigment identification using both purified pigments and tattoo ink formulations. Some 36 organic pigments frequently used in tattoo inks were subjected to py-GC/MS with the aim to establish a pyrogram library. To cross-validate pigment identification, 28 commercially available tattoo inks as well as 18 self-made pigment mixtures were analyzed. Pyrograms of inks and mixtures were evaluated by two different means to work out the most reliable and fastest strategy for an otherwise rather time-consuming data review. Using this approach, the declaration of tattoo pigments currently used on the market could be verified. The pyrolysis library presented here is also assumed suitable to predict decomposition patterns of pigments when affected by other degradation scenarios, such as sunlight exposure or laser irradiation. Thus, the consumers’ risk associated with the exposure to toxicologically relevant substances that originate from pigment decomposition in the dermal layers of the skin can be assessed. Differentiation between more or less harmful pigments for this field of application now will become feasible.

Use of genetically manipulated Salmonella typhimurium strains to evaluate the role of human sulfotransferases in the bioactivation of nitro- and aminotoluenes

Various nitro- and aminotoluenes demonstrated carcinogenic activity in rodent studies, but were inactive or weakly active in conventional in vitro mutagenicity assays. Standard in vitro tests do not take into account activation by certain classes of enzymes. This is true in particular for sulfotransferases (SULTs). These enzymes may convert aromatic hydroxylamines and benzylic alcohols, two major classes of phase-I metabolites of nitro- and aminotoluenes, to reactive esters. Here it is shown that expression of certain human SULTs in Salmonella typhimurium TA1538 or TA100 strongly enhanced the mutagenicity of various nitrotoluenes and nitro- and amino-substituted benzyl alcohols. Human SULT1A1, SULT1A2, and SULT1C2 showed the strongest activation. The observation that some nitrotoluenes as well as some aminobenzyl alcohols were activated by SULTs in the absence of cytochromes P450 implies that mutagenic sulfuric esters were formed at both the exocyclic nitrogen and the benzylic carbon, respectively. Nitroreductase deficiency (using strain YG7131 instead of TA1538 for SULT1A1 expression) did not affect the SULT-dependent mutagenicity of 1-hydroxymethylpyrene (containing no nitro group), moderately enhanced that of 2-amino-4-nitrobenzyl alcohol, and drastically attenuated the effects of nitrobenzyl alcohols without other substituents. The last finding suggests that either activation occurred at the hydroxylamino group formed by nitroreductase or the nitro group (having a strong -M effect) had to be reduced to an electron-donating substituent to enhance the reactivity of the benzylic sulfuric esters. The results pointed to an important role of SULTs in the genotoxicity of nitrotoluenes and alkylated anilines. Activation occurs at nitrogen functions as well as benzylic positions.

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.

Formation of highly toxic hydrogen cyanide upon ruby laser irradiation of the tattoo pigment phthalocyanine blue

Since laser treatment of tattoos is the favored method for the removing of no longer wanted permanent skin paintings, analytical, biokinetics and toxicological data on the fragmentation pattern of commonly used pigments are urgently required for health safety reasons. Applying dynamic headspace—gas chromatography with mass spectrometric detection (DHS—GC/MS) and comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GCxGC—ToF-MS), we identified 1,2-benzene dicarbonitrile, benzonitrile, benzene, and the poisonous gas hydrogen cyanide (HCN) as main fragmentation products emerging dose-dependently upon ruby laser irradiation of the popular blue pigment copper phthalocyanine in suspension. Skin cell viability was found to be significantly compromised at cyanide levels of ≥1 mM liberated during ruby laser irradiation of >1.5 mg/ml phthalocyanine blue. Further, for the first time we introduce pyrolysis-GC/MS as method suitable to simulate pigment fragmentation that may occur spontaneously or during laser removal of organic pigments in the living skin of tattooed people. According to the literature such regular tattoos hold up to 9 mg pigment/cm² skin.

Tattoo ink nanoparticles in skin tissue and fibroblasts

Tattooing has long been practised in various societies all around the world and is becoming increasingly common and widespread in the West. Tattoo ink suspensions unquestionably contain pigments composed of nanoparticles, i.e., particles of sub-100 nm dimensions. It is widely acknowledged that nanoparticles have higher levels of chemical activity than their larger particle equivalents. However, assessment of the toxicity of tattoo inks has been the subject of little research and ink manufacturers are not obliged to disclose the exact composition of their products. This study examines tattoo ink particles in two fundamental skin components at the nanometre level. We use atomic force microscopy and light microscopy to examine cryosections of tattooed skin, exploring the collagen fibril networks in the dermis that contain ink nanoparticles. Further, we culture fibroblasts in diluted tattoo ink to explore both the immediate impact of ink pigment on cell viability and also to observe the interaction between particles and the cells.

Introduction of dermatome shaving as first line treatment of chronic tattoo reactions

BACKGROUND/AIMS

Chronic tattoo reactions requiring treatment have increased. Laser removal is not ideal for removal of allergic reactions. Surgical removal of culprit pigment situated in the outer dermis by dermatome shaving is rational and need to be revisited.

MATERIALS/METHODS

Fifty four tattoos with chronic reactions in 50 patients were treated with dermatome shaving. Tattoos with red/red nuances dominated the material. In total, 52 operations were performed in infiltration and 2 in general anaesthesia. Shaving was performed to the level in the dermis free of tattoo pigment as assessed visually by the surgeon.

RESULTS

Operative complications were few. Healing occurred over weeks as normal for this procedure. On a rating scale from 0 to 4, 4 as most severe, the patient's severity rating of symptoms in their tattoo declined from 3.2 pre-operatively to 1.0, 0.8 and 0.7 after 3, 6 and 12 months, respectively. Burden of operation was rated low. Patient satisfaction was high.

DISCUSSION/CONCLUSION

Dermatome shaving is efficient and with few complications, and is proposed as first line treatment of chronic tattoo reactions. Shaving of such reactions apparently has been neglected during enthusiastic introduction of laser approaches, which in the treatment of allergic tattoo reactions may be relatively contra indicated and of special risk.

Complications of decorative tattoos: recognition and management

Tattooing is an ancient practice that enjoys continued popularity. Although a modern, professionally performed tattoo is generally safe, complications can occur. A skin biopsy of all tattoo reactions is recommended as some tattoo reactions have systemic implications. Tattoo-related infections are seen days to decades after tattooing, and range from acute pyogenic infections to cutaneous tuberculosis. In particular, non-tuberculous mycobacterial infections happen in tattoos with increasing frequency and are introduced at the time of tattooing through contaminated ink or water used to dilute inks. Despite a transition in tattoo pigments from metal salts to industrial azo dyes, hypersensitivity reactions also persist, and include eczematous, granulomatous, lichenoid, and pseudoepitheliomatous patterns (among others). Granulomatous tattoo reactions can be a clue to cutaneous or systemic sarcoidosis, particularly in the setting of interferon use. Pseudoepitheliomatous tattoo reactions have substantial overlap with squamous cell carcinoma and keratoacanthoma, making diagnosis and management difficult. Other malignancies and their benign mimics can occur in tattoos, raising questions about the safety of tattoo ink and its role in carcinogenesis.

Manufactured nanomaterials: categorization and approaches to hazard assessment

Nanotechnology offers enormous potential for technological progress. Fortunately, early and intensive efforts have been invested in investigating toxicology and safety aspects of this new technology. However, despite there being more than 6,000 publications on nanotoxicology, some key questions still have to be answered and paradigms need to be challenged. Here, we present a view on the field of nanotoxicology to stimulate the discussion on major knowledge gaps and the critical appraisal of concepts or dogma. First, in the ongoing debate as to whether nanoparticles may harbour a specific toxicity due to their size, we support the view that there is at present no evidence of 'nanospecific' mechanisms of action; no step-change in hazard was observed so far for particles below 100 nm in one dimension. Therefore, it seems unjustified to consider all consumer products containing nanoparticles a priori as hazardous. Second, there is no evidence so far that fundamentally different biokinetics of nanoparticles would trigger toxicity. However, data are sparse whether nanoparticles may accumulate to an extent high enough to cause chronic adverse effects. To facilitate hazard assessment, we propose to group nanomaterials into three categories according to the route of exposure and mode of action, respectively: Category 1 comprises nanomaterials for which toxicity is mediated by the specific chemical properties of its components, such as released ions or functional groups on the surface. Nanomaterials belonging to this category have to be evaluated on a case-by-case basis, depending on their chemical identity. Category 2 focuses on rigid biopersistent respirable fibrous nanomaterials with a specific geometry and high aspect ratio (so-called WHO fibres). For these fibres, hazard assessment can be based on the experiences with asbestos. Category 3 focuses on respirable granular biodurable particles (GBP) which, after inhalation, may cause inflammation and secondary mutagenicity that may finally lead to lung cancer. After intravenous, oral or dermal exposure, nanoscaled GBPs investigated apparently did not show 'nanospecific' effects so far. Hazard assessment of GBPs may be based on the knowledge available for granular particles. In conclusion, we believe the proposed categorization system will facilitate future hazard assessments.

Black tattoos entail substantial uptake of genotoxicpolycyclic aromatic hydrocarbons (PAH) in human skin and regional lymph nodes

Hundreds of millions of people worldwide have tattoos, which predominantly contain black inks consisting of soot products like Carbon Black or polycyclic aromatic hydrocarbons (PAH). We recently found up to 200 μg/g of PAH in commercial black inks. After skin tattooing, a substantial part of the ink and PAH should be transported to other anatomical sites like the regional lymph nodes. To allow a first estimation of health risk, we aimed to extract and quantify the amount of PAH in black tattooed skin and the regional lymph nodes of pre-existing tattoos. Firstly, we established an extraction method by using HPLC – DAD technology that enables the quantification of PAH concentrations in human tissue. After that, 16 specimens of human tattooed skin and corresponding regional lymph nodes were included in the study. All skin specimen and lymph nodes appeared deep black. The specimens were digested and tested for 20 different PAH at the same time.PAH were found in twelve of the 16 tattooed skin specimens and in eleven regional lymph nodes. The PAH concentration ranged from 0.1–0.6 μg/cm² in the tattooed skin and 0.1–11.8 μg/g in the lymph nodes. Two major conclusions can be drawn from the present results. Firstly, PAH in black inks stay partially in skin or can be found in the regional lymph nodes. Secondly, the major part of tattooed PAH had disappeared from skin or might be found in other organs than skin and lymph nodes. Thus, beside inhalation and ingestion, tattooing has proven to be an additional, direct and effective route of PAH uptake into the human body.

Adverse reactions after tattooing: review of the literature and comparison to results of a survey

The number of tattooed people has substantially increased in the past years. Surveys in different countries reveal this to be up to 24% of the population. The number of reported adverse reactions after tattooing has also increased including infections, granulomatous and allergic reactions and tumors. However, the case reports do not reflect the frequency of adverse reactions. This review compares the medically documented adverse reactions published in 1991-2011 with the findings of a nation-wide survey that recently revealed the features and health problems associated with tattoos. To compare the data with the survey, the sex of patients was reported and the location and color of tattoos were evaluated. The results show clearly that colored tattoo inks are mainly responsible for adverse skin reactions and that tattoos on the extremities are involved most.