Tattoo-Associated Skin Reactions: A Danish Population-Based Survey in 5,914 Tattooed Individuals.

BACKGROUND: In Europe, Australia, and the USA, the estimated overall prevalence of tattooing is around 10-20%. Tattoo ink often comprises harmful chemicals and epidemiological studies on adverse effects of tattoos are lacking. OBJECTIVES: We aimed to estimate the prevalence of tattoo-associated skin reactions in the general Danish population and describe individuals with tattoo-associated skin reactions by socio-demographic factors and tattoo characteristics. METHODS: The study was based on respondents aged 16 years or older from a population-based 2021 survey entitled "How are you?" conducted in the Central Denmark Region (n = 33,925). Logistic regression was used to characterise individuals with tattoo-associated skin reactions by socio-demographic factors (gender, age, educational level, and ethnic background). Also, the relationship between size, age and colour of the tattoo, and tattoo-associated skin reactions was studied. Model 1 was adjusted for all socio-demographic variables (gender, age, educational level, and ethnic background); model 2, for all socio-demographic variables and tattoo characteristics (size, age, and colour). RESULTS: In total, 21.1% reported that they had at least one tattoo, 10.2% hereof reported that they had experienced tattoo-associated skin reactions (itching, pain, inflammation, and swelling) beyond the first 3 weeks after the tattoo was made. Lower age (16-44 years) (adjusted odds ratio (AOR) ≥1.75), larger tattoos (AOR ≥1.61) and having had tattoos for more than 10 years (AOR = 2.92, 95% confidence interval 1.45-5.88) increased the odds of tattoo-associated skin reactions. In general, tattooed individuals with colours other than black had higher odds of tattoo-associated skin reactions. CONCLUSION: Among participants with at least one tattoo, 10.2% had experienced tattoo-associated skin reactions beyond the first 3 weeks after their tattoo was made. This finding highlights the need for safer tattoo inks to prevent the adverse health problems experienced by many individuals with tattoos.

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.

On the mechanism of painful burn sensation in tattoos on magnetic resonance imaging (MRI). Magnetic substances in tattoo inks used for permanent makeup (PMU) identified: Magnetite, goethite, and hematite.

BACKGROUND: Persons with cosmetic tattoos occasionally experience severe pain and burning sensation on magnetic resonance imaging (MRI). OBJECTIVE: To explore the culprit magnetic substances in commonly used permanent makeup inks. MATERIAL AND METHODS: 20 inks used for cosmetic tattooing of eyebrows, eyeliners, and lips were selected. Ink bottles were tested for magnetic behavior with a neodymium magnet. Eight iron oxide inks qualified for the final study. Metals were analyzed by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The magnetic fraction of inks was isolated and analyzed by X-ray fluorescence (XRF). Magnetic iron compounds were characterized by Mössbauer spectroscopy and powder X-ray diffraction (XRD). RESULTS: ICP-MS showed iron in all magnetic samples, and some nickel and chromium. Mössbauer spectroscopy and XRD detected ferromagnetic minerals, particularly magnetite, followed by goethite and hematite. CONCLUSION: This original study of cosmetic ink stock products made with iron oxide pigments reports magnetic impurities in inks for cosmetic tattooing, e.g., magnetite, goethite, and hematite. These may be the main cause of MRI burn sensation in cosmetic tattoos. The mechanism behind sensations is hypothesized to be induction of electrical stimuli of axons from periaxonal pigment/impurity activated by magnetic force. Magnetite is considered the lead culprit.

Psoriasis and seasonal variation: A systematic review on reports from Northern and Central Europe-Little overall variation but distinctive subsets with improvement in summer or wintertime.

BACKGROUND: Positive influence of the sun on psoriasis is a common assumption in dermatology. Other season-related factors such as mental health may interfere. However, the role of seasonal effects on psoriasis needs to be clarified. This review aims to systematically analyze the literature on seasonal variation on psoriasis with emphasis on Northern and Central Europe representing temperate climate conditions. MATERIALS AND METHODS: Enrolled literature was identified through PubMed, EMBASE, and BIOSIS. An additional manual search of old reports before the introduction of efficient modern therapies, which can interfere with the spontaneous disease, was performed. RESULTS: Thirteen studies were enrolled. About 50% of psoriasis patients were stable and showed no seasonal difference between seasons. Approximately 30% improved in summer, and 20% performed better in winter, some with marked summer worsening. European results matched international reports from different continents and hemispheres with climate extremes. The psychological effects could not be ruled out. CONCLUSION: About 50% of psoriasis patients experience a season-independent disease, however, with a subset of patients who do better in summer. Others again do better in winter, with a few of these having marked worsening in warm periods. Individual season-related activity records should be paid proper attention to when considering light therapy or climatotherapy as a treatment.

Scleroderma en Coup de Sabre, Parry-Romberg Hemifacial Atrophy and Associated Manifestations of the Eye, the Oral Cavity and the Teeth: A Danish Follow-Up Study of 35 Patients Diagnosed between 1975 and 2015.

BACKGROUND: Scleroderma en coup de sabre (ECDS) and Parry-Romberg idiopathic hemifacial atrophy (IHA) may affect the eyes, oral cavity, teeth and possibly the brain. OBJECTIVE: Systematic follow-up study of ECDS/IHA-associated manifestations including ophthalmic and dental status. METHODS: Medical records of ECDS and IHA patients diagnosed in a 40-year period (1975-2015) were reviewed, and patients were re-examined. RESULTS: Thirty-five patients were included. Twenty-two patients (63%) had ECDS and 4 patients (11%) IHA. In 9 cases (26%), ECDS and IHA were found in the same patient. The ipsilateral eye was affected in 9 patients (26%). Ipsilateral abnormalities of the teeth and the tongue were found in 13 (46%) out of 28 examined. Eleven (31%) had extrafacial scleroderma on the trunk or the extremities. Neurological findings were not verified as ECDS/IHA related. CONCLUSION: ECDS and IHA are related and often overlap with concomitant affections of the connective tissues of the face on the ipsilateral side. Ocular and dental abnormalities are common and follow the distribution of the primary affection, for example, a paramedian line in the front and segmental affection of the maxilla and the mandible. The affections point to predisposing dysmorphogenetic events in embryonal life affecting the face, with abnormality of crest cells at the stage when they migrate from behind over the scalp or laterally to the face to mix up with mesenchymal tissues of the frontonasal, maxillary and mandibular processes. The study emphasizes that routine evaluation of ECDS and IHA should include ophthalmological and dental specialist examinations.

Tattooist-Associated Tattoo Complications: "Overworked Tattoo," "Pigment Overload" and Infections Producing Early and Late Adverse Events.

BACKGROUND: Tattooist-related technical failures of tattooing were hitherto unstudied and related to clinical complications. Tattooing requires talent, training and experience. Amateurism is a challenge in popular tattoo industry with no formal education and certification of the tattooists. OBJECTIVE: To study technical tattoo failures causing disease in a consecutive hospital material of tattoo complications. MATERIAL: 574 patients with 702 tattoo complications referred to the "Tattoo Clinic" (a subspecialised dermatological clinic) were enrolled. Patients were examined clinically and classified with respect to the cause of complication. RESULTS: 147 (21%) tattooist and tattoo studio-related complications were recorded, i.e. excessive pigment installed in the dermis with "pigment overload" in 64 (9%), tattoo "needle trauma" with "overworked tattoos" in 43 (6%), contaminated ink causing infection in 20 (3%), and other sources of infections related to tattooing in 20 (3%). Pain and discomfort were particularly common as well as long-term complications including scarring induced by "needle trauma." "Pigment overload" with black pigment carried a special risk of granulomatous inflammation and sarcoid granuloma and was observed in 12/35 (34%) of punch biopsies taken from tattoos with "pigment overload." Keratoacanthoma associated with trauma was observed in 1 case. 82% of complications were related to professional tattooists working in a tattoo studio and 18% to amateurs. CONCLUSION: Technical failures of tattooing are associated with medical tattoo complications. "Needle trauma" with major skin damage, e.g. "overworked tattoo," and installation of excessive pigment, e.g. "pigment overload," and (re)use of contaminated tattoo ink bottles are identified failures calling for preventive intervention.

Fluorescent fibre-optic confocal characterization of in vivo epidermal changes in atopic eczema.

BACKGROUND/AIMS: Fibre-optic confocal imaging (FOCI) allows non-invasive visualization of live skin in vivo. A contrast agent, a fluorophore, is injected into the dermis. FOCI images are horizontal optical sections with cellular resolution. The aim was to study in vivo epidermal changes and the cellular structure of keratinocytes in moderate to severe atopic eczema (AE). METHODS: Eight patients with AE with active lesions on the forearms were studied and compared to a control group of six healthy individuals, and two cases of AE without activity. Fluorescein sodium was used as fluorophore. A hand-held fibre-optic laser scanner (Stratum® ) was used. The study included morphometric analyses. RESULTS: The confocal in vivo images identified characteristic features of epidermis and keratinocytes in active AE vs healthy skin controls. FOCI could non-invasively image acanthosis, spongiosis, and parakeratosis in AE. Epidermal oedema and micro-vesicles were visualized. Morphometry based on FOCI demonstrated 14% increased width of keratinocytes of atopic skin vs healthy controls. The epidermal structures and organization in distinctive cell layers were deviant as a result of the disease. CONCLUSIONS: Fibre-optic confocal imaging can visualize essential epidermal structures of atopic eczema directly in vivo, in real-time, and with cellular resolution thus without disturbing the natural state of the skin. FOCI is primarily a research tool, but with a potential to become used in the clinic for non-invasive microscopic diagnosis of AE and monitoring of effect of therapies.

High-frequency ultrasound skin thickness: Comparison of manual reading and automatic border detection includes assessment of interobserver variation of measurement.

BACKGROUND: Twenty megahertz ultrasound is the preferred method for in vivo measurement of skin thickness. This study on methodology aimed to compare operator-managed or "manual" measurement of skin thickness (MM) with measurement by automatic border detection (ABD). METHODS: The skin thickness of the flexor mid-forearm was measured in 48 subjects (subgroups 32 and 16) with the DermaScan C® (Cortex Technology). MM and ABD were performed on the same scans by two experienced operators. MM is measured on the peak of interface A-mode echoes representing the epidermal surface and the dermis-subcutis interface, while ABD measures on the slope of the echoes, for example, the acoustic contour. RESULT: Automatic border detection measured the skin about 20% thicker (mean: 0.94/0.89 mm, SD: 0.09/0.11) in comparison with MM (mean: 1.25/1.22 mm, SD: 0.09/0.12), P < .001. The two methods correlated, r = .9443 and .8663. Two individual researchers reached very close results using MM, that is, mean 0.91 and 0.93 mm, and the interobserver variation was nonsignificant. CONCLUSION: MM and ABD for ultrasound skin thickness measurement rely on different principles and consequently measure skin thickness differently, with ABD overestimating the thickness with about 20%. MM measures anatomically more correct and is preferred in research. MM has been validated against area-based thickness measurement without contour artifact and produced identical results. ABD is less operator-dependent and applicable to field studies, and useful in the beauty industry to characterize aged skin. The two methods of recording each have a scene of use.

Tattoo pigment agglomerates measured in commercial ink stock products by computerised light microscopy.

BACKGROUND: The incidence of clinical complications such as granuloma formation and sarcoidosis is often seen in black tattoos and may be associated with agglomeration of black pigment. AIM: To measure count and dimensions of agglomerates in black tattoo inks vs red inks and to compare old inks and new inks of identical brands. METHOD: Examination was performed by light microscopy (Olympus BX51™ ) with magnification 40X, immersion oil. Photographs (Jenoptik Gryphax RGB camera) were taken of each ink sample and analysed by ImageJ software; count, area, width, height, circumference and circularity index were measured. Agglomerates were defined as width and height of objects above 800 nm. Twenty-one new unopened black inks and 17 new unopened red inks were compared. Furthermore, five old black inks and five old red inks, that had been opened and stocked for over 2 years, were compared with new products of the same brands. RESULTS: Black agglomerates were area wise and with respect to width, height and circumference significantly larger compared with red agglomerates and more circularly shaped. Count of agglomerates was lower in black inks than in red inks, in accordance with bigger dimensions of black agglomerates. Comparison of old and new inks indicated old inks have larger agglomerates but variable bottle size and storage conditions may have confounded results. CONCLUSION: Pigment agglomerates in black tattoo ink stock products were sized larger than agglomerates in red inks. Agglomerates found directly in black inks may predispose to granuloma formation in black tattoos causing sarcoid reaction.

Tattoo pigment agglomerates measured in skin biopsies by computerised light microscopy: Study of 161 patients with adverse reactions in black and red tattoos.

BACKGROUND: Black tattoo reactions are suggested to be foreign body reactions manifested as papulo-nodular inflammation that is associated with active sarcoidosis. AIM: To study the morphology of black and red pigment agglomerates in skin biopsies from tattoo reactions, referenced to clinical diagnoses. METHOD: Agglomerate count, area, width, height, circumference and circularity were measured in 161 patients by light microscopy (Olympus BX51™); 161 unstained skin biopsies from 64 black tattoo reactions and 97 reactions in red tattoos with allergy. Images (Jenoptic Gryphax RGB camera) were taken through a 40× objective using immersion oil. Computerised analysis of agglomerates was performed using ImageJ software. Student t test, chi-square test, Fisher Exact test, ANOVA and Bonferroni tests were applied. RESULTS: Comparison of black and red pigment agglomerates showed no overall differences in count, area, width, height or circumference. However, in black tattoo reactions, the count of agglomerates was higher in patients with sarcoidosis (P = .009) vs no sarcoidosis. Black agglomerates were more circular shaped as compared to red, P = .023. In red tattoo reactions, agglomerates in patients with allergic cross-reactivity were slightly more circular (P = .036) vs patients with milder allergy. The count of red agglomerates was lower in patients clinically typed excessive hyperkeratosis (P = .041) compared with other clinical types of allergy. CONCLUSION: Patients with reactions in black tattoos associated with sarcoidosis have increased count of pigment agglomerates vs those without associated sarcoidosis indicating that black pigment agglomeration is one among a number of factors triggering sarcoid tattoo complication. Circular shape of agglomerates may code for bioactivity.

High-frequency (20 MHz) high-intensity focused ultrasound: New Treatment of actinic keratosis, basal cell carcinoma, and Kaposi sarcoma. An open-label exploratory study.

BACKGROUND: Skin cancer is common, growing, challenging, and in need of progress in early-stage treatment. 20 MHz high-intensity focused ultrasound (HIFU) is new and applied to actinic keratosis (AK) and skin cancers for the first time. HIFU of lower frequency is already used in the treatment of internal cancers. MATERIALS AND METHODS: Eight patients with 201 AK lesions, one patient with 7 basal cell carcinomas (reoccurrences after PDT), and one patient with 7 Kaposi sarcoma lesions (4 treated with radiotherapy in the past) were given 1-3 HIFU treatments. Twenty megahertz HIFU was dosed as 150 ms at 0.6-1.2 J/shot applied to target lesions. Probes with different target depths were available. The preferred shot energy and focal depth in AK were 0.9 J and 1.3 mm. A "Sandwich" strategy with HIFU applied in two depths were tried in cancers. The follow-up period was 3-6 months. RESULTS: All AK cleared except 5, giving a cure rate of 97%. Post-treatment lesion healed in 1-2 weeks with no scar. VAS pain was from 1 to 8, and in any case less than experienced with previous PDT. In both basal cell carcinoma (BCC) and sarcoma, healing was confirmed by histological verification. DISCUSSION/CONCLUSION: 20 MHz HIFU was an effective and safe treatment of AK. This new treatment, applicable to any anatomical site, has promising advantages relative to PDT and has the potential to replace or supplement PDT in future. Case-observations indicated that HIFU can be useful in skin cancers as well.

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.

High-frequency (20 MHz) high-intensity focused ultrasound system for dermal intervention: A 12-week local tolerance study in minipigs.

BACKGROUND: High-intensity focused ultrasound (HIFU) operating at 20 MHz is new and applicable to skin. Details of use and instrumentation are not documented. MATERIALS AND METHODS: A GLP compliant 12-week study of Göttingen minipigs (n = 3) was undertaken. Effects of HIFU treatment at different focal depths, energy levels and field size (single shot vs 5 × 5 multiple shots) were studied. Clinical scoring and histology of treated sites were made. RESULTS: High-intensity focused ultrasound showed instant and initial effects with wheal and flare responses followed by delayed inflammatory reactions associated with outer skin necrosis, depending on energy dose. HIFU treatment was tunable in the range 0.3-1.5 J, ablative at higher energy level. Transducers with deeper focal points gave more profound effects, while epidermal effects were comparable. Multiple doses of 5 × 5 shots produced stronger reactions than single dose indicating that nearby applied shots were synergistic. Recovery from single doses was faster than in multidose areas. Clinical scarring at the end point was not seen despite occasional fibrous change of dermis. Findings illustrated intended therapeutic use; no special safety issues of concern were raised. CONCLUSION: The new 20 MHz HIFU was reproducible, tunable and produced targeted effects in the outer skin, for example instant wheal and flare followed by inflammation and possibly necrosis depending on energy setting. Reactions recovered during the study with only minor findings at study end. No special safety concerns were raised. The method can be controlled and modulated, and it is ready for clinical testing of dermatological disease indications including conditions presently treated with lasers.

Tattoo complications and magnetic resonance imaging: a comprehensive review of the literature.

Tattooed patients undergoing magnetic resonance imaging (MRI) can develop cutaneous complications during the procedure. Our aim was to review all published case reports on MRI-induced tattoo complications to identify a possible pattern. So far, 17 cases have been reported. Five (29%) of the cases were in cosmetic tattoos. Symptoms are abrupt and painful with fast onset during MRI, sometimes requiring termination of the procedure. Clinical signs are absent or manifested as inflammation sensed as burning. No thermal skin burns have been recognized. Full recovery is fast, with no sequelae. MRI-induced tattoo complications are uncommon. Patients with cosmetic and traditional tattoos can undergo routine MRI.

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.

High-frequency (20-MHz) high-intensity focused ultrasound (HIFU) system for dermal intervention: Preclinical evaluation in skin equivalents.

BACKGROUND: High-intensity focused ultrasound (HIFU) for non-invasive treatment of a range of internal pathologies including cancers of major organs and cerebral pathologies is in exponential growth. Systems, however, operate at relatively low frequencies, in the range of 200-2000 kHz as required for deep axial penetration of the body. HIFU utilizing frequencies in excess of 15 MHz has so far not been explored, but presents an opportunity to extend the HIFU modality to target specific dermal lesions and small animal research. MATERIALS AND METHODS: A new 20-MHz HIFU system (TOOsonix ONE-R) with narrow focus corresponding to the dermis was studied in acoustic skin equivalents, for example, in a tissue-mimicking gel and in bovine liver. HIFU lesion geometry, depth, and diameter were determined. The temperature increase in the focal point was measured as a function of acoustic power and the duration of HIFU exposure. RESULTS: The system produces highly reproducible ultrasound lesions with predictable and configurable depths of 1-2 mm, thus corresponding to the depth of the human dermis. The lesion geometry was elongated triangular and sized 0.1-0.5 mm, convergent to a focal point skin deep. Focal point temperature ranged between 40 and 90°C depending on the chosen setting. Observations were confirmed ex vivo in bovine liver and porcine muscle. Variation of acoustic power and duration of exposure produced linear effects in the range of the settings studied. Thus, effects could be adjusted within the temperature interval and spatial field relevant for clinical therapy and experimental intervention targeting the dermal layer of human skin. CONCLUSION: The tested 20-MHz HIFU system for dermal applications fulfilled key prerequisite of narrow-field HIFU dedicated to cutaneous applications regarding reproducibility, geometry, and small size of the applied ultrasound lesions. Controlled adjustment of acoustic lesions within the temperature range 40-90°C qualifies the system for a range of non-ablative and ablative applications in dermatological therapy.

Tattoos and skin barrier function: Measurements of TEWL, stratum corneum conductance and capacitance, pH, and filaggrin.

BACKGROUND: Initially after tattooing, the skin barrier function is broken. However, the long-term impact of clinically healed tattoos on this has never been studied. The aim was to investigate the long-term effect on the skin barrier function in normal tattoos and examples of tattoos with chronic inflammatory complication. METHODS: Participants were recruited from the "Tattoo clinic" of the Dermatological Department on Bispebjerg Hospital in Denmark, where patients with complicated tattoo reactions are treated. Transepidermal water loss (TEWL), conductance, capacitance, and pH were measured in tattooed skin with regional control measurements in normal non-tattooed skin. Natural moisturizing factor (NMF) was measured in collected tape strips. RESULTS: Twenty six individuals with 28 tattoos were included, that is, 23 normal tattoos without any pathologic reaction and 5 tattoos with chronic inflammatory complications. No significant differences were found in tattooed versus non-tattooed skin with respect to TEWL (median values 6.6 vs 7.2 g/m2 /h), conductance (76 vs 78 a.u.), pH (5.94 vs 5.79), and NMF (0.58 vs 0.59 mmol/g protein). Capacitance (64 vs 57 a.u.) was higher in tattooed skin compared to non-tattooed skin (P = 0.006). Similar results were found in tattoos with inflammatory reactions. CONCLUSION: Overall, skin tattoos do not affect the long-term skin barrier function markedly. The skin capacitance was, however, affected in tattooed skin areas compared to non-tattooed skin areas.

The revised EEMCO guidance for the in vivo measurement of water in the skin.

BACKGROUND: Noninvasive quantification of stratum corneum water content is widely used in skin research and topical product development. METHODS: The original EEMCO guidelines on measurements of skin hydration by electrical methods and transepidermal water loss (TEWL) by evaporimeter published in 1997 and 2001 have been revisited and updated with the incorporation of recently available technologies. RESULTS: Electrical methods and open-chamber evaporimeters for measurement of TEWL are still the preferred techniques to measure the water balance in the stratum corneum. The background technology and biophysics of these instruments remain relevant and valid. However, new methods that can image surface hydration and measure depth profiles of dermal water content now available. Open-chamber measurement of TEWL has been supplemented with semiopen and closed chamber probes, which are more robust to environmental influence and therefore convenient to use and more applicable to field studies. However, closed chamber methods interfere with the evaporation of water, and the methods cannot be used for continuous monitoring. Validation of methods with respect to intra- and inter-instrument variation remains challenging. No validation standard or test phantom is available. RESULTS AND CONCLUSIONS: The established methods for measurement of epidermal water content and TEWL have been supplemented with important new technologies including methods that allow imaging of epidermal water distribution and water depth profiles. A much more complete and sophisticated characterization of the various aspects of the dermal water barrier has been accomplished by means of today's noninvasive techniques; however, instrument standardization and validation remain a challenge.

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.