Contact allergy epidemics and their controls

The epithelial barrier theory and its associated diseases

The prevalence of many chronic noncommunicable diseases has been steadily rising over the past six decades. During this time, over 350,000 new chemical substances have been introduced to the lives of humans. In recent years, the epithelial barrier theory came to light explaining the growing prevalence and exacerbations of these diseases worldwide. It attributes their onset to a functionally impaired epithelial barrier triggered by the toxicity of the exposed substances, associated with microbial dysbiosis, immune system activation, and inflammation. Diseases encompassed by the epithelial barrier theory share common features such as an increased prevalence after the 1960s or 2000s that cannot (solely) be accounted for by the emergence of improved diagnostic methods. Other common traits include epithelial barrier defects, microbial dysbiosis with loss of commensals and colonization of opportunistic pathogens, and circulating inflammatory cells and cytokines. In addition, practically unrelated diseases that fulfill these criteria have started to emerge as multimorbidities during the last decades. Here, we provide a comprehensive overview of diseases encompassed by the epithelial barrier theory and discuss evidence and similarities for their epidemiology, genetic susceptibility, epithelial barrier dysfunction, microbial dysbiosis, and tissue inflammation.

Chemical-Specific T Cell Tests Aim to Bridge a Gap in Skin Sensitization Evaluation

T cell activation is the final key event (KE4) in the adverse outcome pathway (AOP) of skin sensitization. However, validated new approach methodologies (NAMs) for evaluating this step are missing. Accordingly, chemicals that activate an unusually high frequency of T cells, as does the most prevalent metal allergen nickel, are not yet identified in a regulatory context. T cell reactivity to chemical sensitizers might be especially relevant in real-life scenarios, where skin injury, co-exposure to irritants in chemical mixtures, or infections may trigger the heterologous innate immune stimulation necessary to induce adaptive T cell responses. Additionally, cross-reactivity, which underlies cross-allergies, can only be assessed by T cell tests. To date, several experimental T cell tests are available that use primary naïve and memory CD4+ and CD8+ T cells from human blood. These include priming and lymphocyte proliferation tests and, most recently, activation-induced marker (AIM) assays. All approaches are challenged by chemical-mediated toxicity, inefficient or unknown generation of T cell epitopes, and a low throughput. Here, we summarize solutions and strategies to confirm in vitro T cell signals. Broader application and standardization are necessary to possibly define chemical applicability domains and to strengthen the role of T cell tests in regulatory risk assessment.

Occupational Contact Dermatitis in Construction Workers: A Retrospective Analysis of the North American Contact Dermatitis Group Data, 2001-2020

Background: Construction workers (CWs) are at risk for occupational contact dermatitis (CD) owing to workplace exposures. Objective: Determine the prevalence of occupational allergic CD and characterize common occupational allergens in CWs referred for patch testing in the United States and Canada. Methods: Retrospective cross-sectional analysis of patients patch tested by the North American Contact Dermatitis Group from 2001 to 2020. Results: Of 47,843 patch-tested patients, 681 (1.4%) were CWs. Compared with non-CWs, CWs were more likely to be male (91.0% vs 30.9%) have occupational skin disease (36.9% vs 11.4%) and have hand involvement (37.2% vs 22.5%) (all P < 0.0001). Of 681 CWs, 60.1% (411) had clinically relevant positive patch test reactions, and nearly 1/3 of CWs (128) had occupationally relevant reactions. Most common occupationally relevant allergens were potassium dichromate 0.25% pet. (30.5%, 39/128), bisphenol A epoxy resin 1% pet. (28.1%, 36/128), carba mix 3% pet. (14.8%, 19/128), cobalt (ii) chloride hexahydrate 1% pet. (14.1%, 18/128), and thiuram mix 1% pet. (14.1%, 18/128). Top sources of occupationally relevant allergens were cement/concrete/mortar (20.4%, 46/225), gloves (15.1%, 34/225), and coatings (paint/lacquer/shellac/varnish/stains) (9.8%, 22/225). Conclusions: Occupational CD in North American CWs is common. In this group, frequently identified etiological sources of occupational allergic CD included metals, epoxy resin, and rubber.

Physical, chemical and biological characteristics of clays from Durban (South Africa) for applications in cosmetics

Clay soils are rock-decomposed materials comprised of both clay- and non-clay-like minerals. Clays' physiochemical and mineralogical composition determines their applicability use in cosmetics. Because of their high bioburden, they must be effectively characterized before being incorporated into cosmetics. The scope of the current study was to characterize two different samples of red and white clays for their physical, chemical and biological properties; mined from Durban, South Africa. Characterization was performed using techniques like X-ray fluorescence, X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscope, hydrogen potential, soil colour, oil absorption, swelling capacity, texture, bulk density, plastic and apparent viscosity, sun protection factor and microbiological analysis.

Mass-Spectrometry-Based Research of Cosmetic Ingredients

Cosmetic products are chemical substances or mixtures used on the skin, hair, nails, teeth, and the mucous membranes of the oral cavity, whose use is intended to clean, protect, correct body odor, perfume, keep in good condition, or change appearance. The analysis of cosmetic ingredients is often challenging because of their huge complexity and their adulteration. Among various analytical tools, mass spectrometry (MS) has been largely used for compound detection, ingredient screening, quality control, detection of product authenticity, and health risk evaluation. This work is focused on the MS applications in detecting and quantification of some common cosmetic ingredients, i.e., preservatives, dyes, heavy metals, allergens, and bioconjugates in various matrices (leave-on or rinse-off cosmetic products). As a global view, MS-based analysis of bioconjugates is a narrow field, and LC- and GC/GC×GC-MS are widely used for the investigation of preservatives, dyes, and fragrances, while inductively coupled plasma (ICP)-MS is ideal for comprehensive analysis of heavy metals. Ambient ionization approaches and advanced separation methods (i.e., convergence chromatography (UPC2)) coupled to MS have been proven to be an excellent choice for the analysis of scented allergens. At the same time, the current paper explores the challenges of MS-based analysis for cosmetic safety studies.

Biogeochemical behaviour and toxicology of chromium in the soil-water-human nexus: A review

Chromium (Cr) affects human health if it accumulates in organs to elevated concentrations. The toxicity risk of Cr in the ecosphere depends upon the dominant Cr species and their bioavailability in the lithosphere, hydrosphere, and biosphere. However, the soil-water-human nexus that controls the biogeochemical behaviour of Cr and its potential toxicity is not fully understood. This paper synthesizes information on different dimensions of Cr ecotoxicological hazards in the soil and water and their subsequent effects on human health. The various routes of environmental exposure of Cr to humans and other organisms are also discussed. Human exposure to Cr(VI) causes both carcinogenic and non-carcinogenic health effects via complicated reactions that include oxidative stress, chromosomal and DNA damage, and mutagenesis. Chromium (VI) inhalation can cause lung cancer; however, incidences of other types of cancer following Cr(VI) exposure are low but probable. The non-carcinogenic health consequences of Cr(VI) exposure are primarily respiratory and cutaneous. Research on the biogeochemical behaviour of Cr and its toxicological hazards on human and other biological routes is therefore urgently needed to develop a holistic approach to understanding the soil-water-human nexus that controls the toxicological hazards of Cr and its detoxification.

Insights into Health Risks of Face Paint Application to Opera Performers: The Release of Heavy Metals and Stage-Light-Induced Production of Reactive Oxygen Species

Face paints used by opera performers have been shown to contain high levels of heavy metals. However, whether frequent exposure, via dermal contact and inadvertent oral ingestion, results in occupational diseases is unknown, as is the potential exacerbation of toxicity by high-intensity irradiation from stage lights. In this study, we examined the release of Cr, Cu, Pb, and Zn from 40 face paints and the consequent health risks posed by different practical scenarios involving their use. The results showed that the in vitro bioaccessibility (IVBA) of Cr, Cu, Pb, and Zn in the tested products was, on average, 7.0, 5.5, 19.9, and 7.9% through oral ingestion and 1.1, 2.2, 1.6, and 1.2% through dermal contact, respectively. Stage light irradiation significantly increased the IVBA associated with dermal contact, to the average of 4.8, 34.9, 5.7, and 1.9% for Cr, Cu, Pb, and Zn, respectively. The increase was mainly due to the light-induced generation of reactive oxygen species, particularly hydroxyl free radicals. The vitality and transcriptional response of 3D skin models as well as a quantitative risk assessment of skin sensitization indicated that dermal contact with face paints may induce predictable skin damage and potentially other skin diseases. Long-term exposure to face paints on stage may also pose a non-carcinogenic health risk. The demonstrated health risks to opera performers of face paint exposure should lead to strict regulations regarding the content of theatrical face paints.

Decision making in next generation risk assessment for skin allergy: Using historical clinical experience to benchmark risk

Our aim is to develop and apply next generation approaches to skin allergy risk assessment that do not require new animal test data and better quantify uncertainties. Quantitative risk assessment for skin sensitisation uses safety assessment factors to extrapolate from the point-of-departure to an acceptable human exposure level. It is currently unclear whether these safety assessment factors are appropriate when using non-animal test data to derive a point-of departure. Our skin allergy risk assessment model Defined Approach uses Bayesian statistics to infer a human-relevant metric of sensitiser potency with explicit quantification of uncertainty, using any combination of human repeat insult patch test, local lymph node assay, direct peptide reactivity assay, KeratinoSens™, h-CLAT or U-SENS™ data. Here we describe the incorporation of benchmark exposures pertaining to use of consumer products with clinical data supporting a high/low risk categorisation for skin sensitisation. Margins-of-exposure (potency estimate to consumer exposure level ratio) are regressed against the benchmark risk classifications, enabling derivation of a risk metric defined as the probability that an exposure is low risk. This approach circumvents the use of safety assessment factors and provides a simple and transparent mechanism whereby clinical experience can directly feed-back into risk assessment decisions.

Next generation risk assessment for skin allergy: Decision making using new approach methodologies

Our aim is to develop and apply next generation approaches to skin allergy risk assessment (SARA) that do not require new animal test data and better quantify uncertainties. Significant progress has been made in the development of New Approach Methodologies (NAMs), non-animal test methods, for assessment of skin sensitisation and there is now focus on their application to derive potency information for use in Next Generation Risk Assessment (NGRA). The SARA model utilises a Bayesian statistical approach to infer a human-relevant metric of sensitiser potency and a measure of risk associated with a given consumer exposure based upon any combination of human repeat insult patch test, local lymph node, direct peptide reactivity assay, KeratinoSens™, h-CLAT or U-SENS™ data. Here we have applied the SARA model within our weight of evidence NGRA framework for skin allergy to three case study materials in four consumer products. Highlighting how to structure the risk assessment, apply NAMs to derive a point of departure and conclude on consumer safety risk. NGRA based upon NAMs were, for these exposures, at least as protective as the historical risk assessment approaches. Through such case studies we are building our confidence in using NAMs for skin allergy risk assessment.

Quantitative assessment of sensitizing potency using a dose-response adaptation of GARDskin

Hundreds of chemicals have been identified as skin sensitizers. These are chemicals that possess the ability to induce hypersensitivity reactions in humans, giving rise to a condition termed allergic contact dermatitis. The capacity to limit hazardous exposure to such chemicals depends upon the ability to accurately identify and characterize their skin sensitizing potency. This has traditionally been accomplished using animal models, but their widespread use offers challenges from both an ethical and a scientific perspective. Comprehensive efforts have been made by the scientific community to develop new approach methodologies (NAMs) capable of replacing in vivo assays, which have successfully yielded several methods that can identify skin sensitizers. However, there is still a lack of new approaches that can effectively measure skin sensitizing potency. We present a novel methodology for quantitative assessment of skin sensitizing potency, which is founded on the already established protocols of the GARDskin assay. This approach analyses dose–response relationships in the GARDskin assay to identify chemical-specific concentrations that are sufficient to induce a positive response in the assay. We here compare results for 22 skin sensitizers analyzed using this method with both human and LLNA potency reference data and show that the results correlate strongly and significantly with both metrics (r_LLNA = 0.81, p = 9.1 × 10^–5; r_Human = 0.74, p = 1.5 × 10^–3). In conclusion, the results suggest that the proposed GARDskin dose–response methodology provides a novel non-animal approach for quantitative potency assessment, which could represent an important step towards reducing the need for in vivo experiments.

Trends in preservative allergy: Benzisothiazolinone emerges from the pack

BACKGROUND

Preservatives are used widely in cosmetic, household, and industrial products to prevent microbial growth and spoiling of the products. There has been a recent epidemic of contact allergy to methylisothiazolinone (MI).

OBJECTIVES

To establish emerging trends in preservative contact allergy as MI is replaced.

METHODS

We performed a retrospective study on consecutively patch-tested patients at our center from January 2011 to December 2019.

RESULTS

A total of 7846 consecutively patch-tested patients were included who were patch tested between January 2011 and December 2019. The prevalence of allergy to MI fell from a peak of 9.39% in 2013 to 1.98% in 2019. MI/methylchloroisothiazolinone (MCI) followed a similar trend, with a peak prevalence of 7.85% in 2014 and falling to 1.39% in 2018. The prevalence of contact allergy to benzisothiazolinone (BIT) has increased steadily increased in 2014 from 0.26% (confidence interval [CI] 0.03-0.93) to 3.42% (CI 2.43-4.66) in 2019.

CONCLUSIONS

Our data show a significant increase in the prevalence of contact allergy to BIT over the last 6 years, probably as a consequence of increased use in household products. It is essential to continue to look for emerging trends in contact allergy to enable prompt preventative measures to be taken.

Epidemics of Dermatitis

Allergic contact dermatitis (ACD) remains a globally prevalent disease for both children and adults. The silent ACD epidemic continues to be fueled by the introduction of novel allergens in industrial and household products and the continued presence of known allergens. In 1997, Allan Dillarstone noted a sinusoidal pattern to epidemics when allergenic preservatives were replaced by alternative chemicals within the market, which then similarly increased in allergenicity. A call for public health vigilance and prevention initiatives is needed to intervene in the ACD epidemic.

Allergic contact dermatitis: a significant environmental and occupational skin disease

This review article seeks to provide an overview of allergic contact dermatitis (ACD) as a significant environmental and occupational skin disease, the phases of ACD, its causes from the occupational and environmental perspectives, its detection, the effects of ACD with respect to the social, psychological, occupational, and financial perspectives, and its cure and/or prevention. Human skin is very sensitive and as the largest organ in the body, it is highly prone to direct and indirect contact with the substances from its environment. The skin reacts to these substances (xenobiotics) differently depending on the individual's tolerance level or threshold. Allergic contact dermatitis is a significant environmental and occupational skin disease that should not be ignored in our society because it can affect the quality of life of an affected individual. There are multiple causes of ACD, and these causes of ACD have been discussed from two perspectives: environmental and occupational. The effects of ACD can be psychological, social, financial, and occupational. There is need for more public enlightenment on the effects of ACD as well as a precise understanding that it is not a contagious disease so as to significantly reduce the psychological and social effects of ACD on these patients.

The epidemic of contact allergy to methylisothiazolinone-An analysis of Danish consecutive patients patch tested between 2005 and 2019

BACKGROUND

In 2005, methylisothiazolinone (MI) was allowed as a stand-alone preservative in cosmetics. This resulted in an epidemic of allergic contact dermatitis to MI, mainly affecting women exposed to leave-on cosmetics. Consequently, a regulation of Annex V in the European Union in 2017 banned the use of MI in leave-on cosmetics and reduced the allowed concentration in rinse-off products.

OBJECTIVE

To analyze the temporal trends in contact allergy to MI in Danish patients in relation to key events including European regulations over time.

METHODS

A retrospective study of consecutive patients patch tested with methylisothiazolinone from 2005 to 2019. Demographics and clinical characteristics in terms of MOAHLFA (male, occupational, atopic dermatitis, hand dermatitis, leg dermatitis, facial dermatitis and age >40 years), sources of exposure, and clinical relevance were analyzed in relation to key historical events.

RESULTS

Three hundred eighty of 12 494 patients (3.0%, 95CI: 2.7-3.4%) tested from 2005 to 2019 were sensitized to MI. An increasing trend in the prevalence of MI contact allergy from 2005 to 2019 (P < .01) was observed, although a decline in the absolute number of patch-test positive patients was seen from 2013 and onward. A reduction in leave-on cosmetics as a source of exposure was observed following the legislative ban in 2017, from 24.8% from in 2010 to 2013 to 6.2% in 2017 to 2019 (P < .01).

CONCLUSION

The epidemic of MI contact allergy is declining in absolute terms, although the prevalence in the patch-tested population has not returned to its pre-epidemic levels. The legislative regulation of MI in 2017 has been effective in terms of leave-on cosmetics as a source of exposure in MI allergic patients. The process of post-marketing risk assessment of contact allergens in the European Union needs improvement.

Patch test results of the European baseline series among 1309 patients in Turkey between 2013 and 2019

BACKGROUND

Prevalences of sensitivity to contact allergens change over time as a result of variations in allergen exposure.

OBJECTIVES

The aim of the study was to describe trends in sensitisation to allergens of the European baseline series in Turkey between 2013 and 2019.

METHODS

The patch test results of 1309 patients with suspected allergic contact dermatitis (ACD) were analysed retrospectively, and the prevalence of contact allergies to European baseline series allergens was compared with previous data (for 1998-2005).

RESULTS

A total of 534 (40.8%) patients exhibited one or more positive patch test reaction. The five most frequent allergens were nickel sulfate (19.6%), potassium dichromate (6.5%), cobalt chloride (6%), Myroxylon pereirae resin (5%), and p-phenylenediamine (PPD; 3.7%). Statistically significant increases in the prevalence of sensitisation to methylchloroisothiazolinone/methylisothiazolinone (MCI/MI; P < .001), Myroxylon pereirae resin (P < .001), PPD (P = .008), and fragrance mix I (P = .036) were observed in the 2013 to 2019 period compared with the 1998 to 2005 period. Conversely, positive reactions to neomycin sulfate (P = .029), clioquinol (P = .031), and primin (P = .001) decreased significantly.

CONCLUSION

This study provides a comprehensive profile of ACD in Turkey. The remarkable increase in the MI and MCI/MI contact allergy observed underlines the urgent need for regulatory measures to reduce exposure to MI and MCI/MI in Turkey.

Heavy metals in face paints: Assessment of the health risks to Chinese opera actors

The actors in Chinese operas are exposed to heavy metals through the face paints that they use but the resulting health risks are unknown. We therefore conducted a survey of face paint use by Chinese opera actors and then assayed 91 paint samples of various paint brands and colors for their contents of eight heavy metals. The potential health risks of heavy metal exposure due to face paint use were determined as well. The average concentrations of As, Cd, Co, Cr, Cu, Ni, Pb, and Zn were 1.8, 0.6, 4.4, 23.1, 610, 7.6, 16.2, and 10,415 μg/g, respectively, and at least four of the eight elements were detected in all samples. Samples from the most frequently paint brands were the most highly contaminated, especially with Zn, whose mass contribution was extremely high (18.3%). Moreover, contamination of the paint was color-specific, with significantly higher heavy metal levels in brown (As, Cr, and Ni), black (Co and Zn), red (Pb), and green (Cu) paints. The total carcinogenic risk posed by the metals in 25 paint samples ranged between 0.01% and 0.96%, with the highest risk that of Cr. Thus, lifetime exposure to Cr-containing paints would result in a high probability of the actor developing cancer. The findings of our study highlight the need for Chinese regulations addressing the heavy metals in face paints, especially Cr. Capsule: Chinese opera actors have a high probability of developing cancer due to a lifetime exposure to high levels of heavy metals in their face paints.

Systemic stereoselectivity study of bromothalonil: stereoselective bioactivity, toxicity, and degradation in vegetables and soil

BACKGROUND

The chiral pesticide bromothalonil is widely used to control anthracnose disease on fruits and vegetables in China. The pesticidal activity, ecotoxicological effects and environmental behavior of bromothalonil and its enantiomers are still unclear.

RESULTS

Bromothalonil presented effective biocidal activities against the tested fungi, its enantiomers showed distinct inhibitory activities against different fungal species. The bioactivities of (+)-bromothalonil was 1.29-10.77 times higher than (-)-bromothalonil toward Rhizoctonia solani, Botrytis cinerea, Curvularia lunata, Corynespora cassiicola, Colletotrichum siamense, and Colletotrichum musae, while the effect pattern was opposite for Colletotrichum cliviicola. Based on the acute toxicity test, bromothalonil was very toxic to Eisenia foetida (E. foetida). Bromothalonil also damaged the lysosomal membrane and exhibited potential genotoxicity toward E. foetida. Moreover, (+)-bromothalonil presented lower toxicity than (-)-bromothalonil. Stereoselective degradation was investigated in tomato, cucumber, chieh-qua, and soil. The half-life values of bromothalonil degradation ranged from 7.14 to 24.75 days, indicating that bromothalonil was easily degraded. Additionally, (+)-bromothalonil degraded 1.2-1.75 times faster than (-)-bromothalonil in the four matrices.

CONCLUSION

This is the first systemic assessment of the stereoselectivity of bromothalonil. Based on the obtained half-life, EC₅₀ and LC₅₀ values, bromothalonil is an easily degraded, broad-spectrum biocidal but very toxic pesticide. (+)-Bromothalonil was more degradable in vegetables and soil and showed clearly higher bioactivity toward target organisms and lower toxicity to E. foetida than (-)-bromothalonil. Therefore, the stereoselectivity of bromothalonil enantiomers should be fully considered in comprehensive environmental and ecological risk assessments in future work. © 2020 Society of Chemical Industry.

Risk of human exposure to metals in some household hygienic products in Nigeria

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Metal content of 27 household hygienic products available in Nigeria was determined.

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SED values for metals in these products were below tolerable intake levels.

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MoS values indicate that they are reasonably safe for human use.

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However, products contained significant amounts of toxic and allergenic metals.

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Effluents from use of products are likely sources of metals to the environment.

This study presents data on the levels and risk of human exposure to Cd, Pb, Cr, Ni, Cu, Co, Mn, Zn and Fe in some popular brands of household hygienic products (HHPs) available in Nigeria. The HHPs were digested with a mixture of HNO₃, HCl and HClO₄ in a ratio of 1:3:1 and the concentrations of the selected metals were quantified by atomic absorption spectrophotometry. The metal concentrations (in μg g⁻¹) in these products ranged from 0.4 to 5.4, <0.09–47.0, <0.12–43.7, <0.06–7.5, <0.12–9.5, <0.06–15.0, <0.09–24.5, 9.0–675 and 62.4–434 for Cd, Pb, Cr, Cu, Co, Ni, Mn, Zn and Fe respectively. The systemic exposure dosages for the metals, arising from the use of these HPPs, were less than their respective provisional tolerable daily intake/recommended dietary allowance values. The household hygienic products are safe to use by humans based on the margin of safety values that were all above 100. However, the products contained significant levels of toxic (Cd and Pb), allergenic (Ni and Cr) and other low toxicity metals (Mn, Zn and Fe), which could be a potential threat to the environment.

Concise Review of Nickel Human Health Toxicology and Ecotoxicology

Nickel (Ni) metal and Ni compounds are widely used in applications like stainless steel, alloys, and batteries. Nickel is a naturally occurring element in water, soil, air, and living organisms, and is essential to microorganisms and plants. Thus, human and environmental nickel exposures are ubiquitous. Production and use of nickel and its compounds can, however, result in additional exposures to humans and the environment. Notable human health toxicity effects identified from human and/or animal studies include respiratory cancer, non-cancer toxicity effects following inhalation, dermatitis, and reproductive effects. These effects have thresholds, with indirect genotoxic and epigenetic events underlying the threshold mode of action for nickel carcinogenicity. Differences in human toxicity potencies/potentials of different nickel chemical forms are correlated with the bioavailability of the Ni2+ ion at target sites. Likewise, Ni2+ has been demonstrated to be the toxic chemical species in the environment, and models have been developed that account for the influence of abiotic factors on the bioavailability and toxicity of Ni2+ in different habitats. Emerging issues regarding the toxicity of nickel nanoforms and metal mixtures are briefly discussed. This review is unique in its covering of both human and environmental nickel toxicity data.

An insight into toxicity and human-health-related adverse consequences of cosmeceuticals - A review

In recent years, the use of cosmeceutical-based personal care and beauty products has ever increased, around the world. Currently, an increasing number of compounds are being assimilated in the formulation of cosmetic products as preservatives, fragrances, surfactants, etc. to intensify the performance, quality, value, and lifespan of cosmetics. Nevertheless, many of these chemical additives pose toxic effects to the human body, exhibiting health risks from a mild hypersensitivity to life-threatening anaphylaxis or lethal intoxication. Therefore, the indiscriminate application of cosmeceuticals has recently become a mounting issue confronting public health. The present review focuses on exposure to a large variety of toxic substances used in cosmetic formulations such as 1,4-dioxane formaldehyde, paraformaldehyde, benzalkonium chloride, imidazolidinyl urea, diazolidinyl urea, trace heavy metals, parabens derivatives, phthalates, isothiazolinone derivatives (methylchloroiso-thiazolinone, and methylisothiazolinone), methyldibromo glutaronitrile, and phenoxy-ethanol. The biological risks related to these substances that they can pose to human health in terms of cytotoxicity, genotoxicity, mutagenicity, neurotoxicity oestrogenicity or others are also discussed. Researchers from academia, consultancy firms, governmental organizations, and cosmetic companies should carry out further progress to keep updating the consumers regarding the dark-sides, and health-related harmful apprehensions of cosmetics. In addition, the industry-motivated initiatives to abate environmental impact through green, sustainable and eco-friendly product development grasp significant perspective.

Severe Metal Hypersensitivity Following Internal Fixation of an Ankle Fracture: A Case Report

CASE

A 67-year-old woman underwent internal fixation of an ankle fracture. Ten days postoperatively, the patient developed systemic hives, difficulty breathing, and oral swelling. At 8 weeks postoperatively, the hardware was removed because of a suspected metal hypersensitivity. Despite experiencing perioral edema and difficulty breathing after the hardware removal, she had complete resolution of the symptoms at the 2-week, 6-week, and 12-month follow-up appointments.

CONCLUSION

Hypersensitivities to metal-based implants can develop and cause local and systemic reactions. Orthopaedic surgeons should inquire about a history of metal allergies, and possibly perform allergy testing for patients with a history suggestive of metal hypersensitivities. Consideration should be given for hospital admission following hardware removal for patient monitoring.

Non-cancer, cancer, and dermal sensitization risk assessment of heavy metals in cosmetics

The heavy metal content of cosmetics may be a cause for concern in that exposure to these metals is associated with adverse consequences. Thus, the aim of this study was to assess consequences attributed to exposure to heavy metals in cosmetics as determined by non-cancer, cancer, and sensitization risks methodologies. The quantification and exposure assessments of aluminum (Al), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), arsenic (As), lead (Pb), mercury (Hg), cadmium (Cd), antimony (Sb), and titanium (Ti) were performed by inductively coupled plasma-mass spectrometry. The non-cancer risk assessment of Al, Cr3+, Mn, Fe, Co, Ni, Cu, Zn, Cd, Sb, and Ti in cosmetic samples resulted in a margin of safety (MOS) greater than 100 or a hazard index (HI) of less than 1. However, the probability of lifetime cancer risk (LCR) resulting from dermal exposure to heavy metals from cosmetics exceeded the acceptable risk levels (LCR > 10-5). An exposure-based sensitization quantitative risk assessment determined that the ratios of acceptable exposure level to consumers for Ni, Co, Cu, or Hg were above 1, suggesting an absence of skin-sensitizing potential. For an average daily user of lip cosmetics, the estimated intakes of heavy metals were within the acceptable daily intake (ADI). The percentage of heavy users for which metal intakes exceeded ADIs were 20.37% for Pb, 9.26% for Mn, 1.85% for Cr3+, and 1.85% for Cr6+, respectively. Data suggested that the heavy metals present in cosmetics do not appear to pose a serious risk to health. However, for heavy users of lip cosmetics, contamination with some heavy metals, such as Pb, Mn, and Cr needs to be minimized.

Evaluation of human exposure to metals from some commonly used hair care products in Nigeria

The concentrations of nine metals, namely, cadmium (Cd), lead (Pb), chromium (Cr), copper (Cu), cobalt (Co), nickel (Ni), manganese (Mn), zinc (Zn), and iron (Fe), were determined in 26 brands of hair care products including hair relaxers, conditioners and shampoos. The study was aimed at providing information on the possible risks arising from heavy metals associated with the use of these products. The concentrations of the metals were determined by means of atomic absorption spectrophotometry after digestion of the samples with a mixture of acids. The concentrations of the respective metals in hair relaxers, shampoos and conditioners were found to be 0.8–2.5, 0.6–3.0, <LOQ-2.8 μg g⁻¹ Cd; 4.5–26.0, <LOQ-28.0, <LOQ-425 μg g⁻¹ Pb; <LOQ-0.6, <LOQ-3.4, <LOQ-4.2 μg g⁻¹ Cr; <LOQ-3.5, <LOQ-6.0, <LOQ-3.5 μg g⁻¹ Cu; <LOQ-7.0, <LOQ-7.0, 0.5–4.5 μg g⁻¹ Co; 1.0-5.5, <LOQ-10.5, 1.5–6.0 μg g⁻¹ Ni; <LOQ-9.0, 2.0–25.5, <LOQ-15 μg g⁻¹ Mn; 36.5–48.0, 35.5–1080 μg g⁻¹, 30.0–69.0 μg g⁻¹ Zn; and 84.5–123, 66.7–284, 57.6–153 μg g⁻¹ Fe respectively. The systemic exposure dosage (SED) values of the studied metals were below their respective provisional tolerable daily intakes (PTDI)/recommended daily intakes (RDI), while the margins of safety were greater than 100 which indicate that these products are safe to use.

Cystathionine metabolic enzymes play a role in the inflammation resolution of human keratinocytes in response to sub-cytotoxic formaldehyde exposure

Low-level formaldehyde exposure is inevitable in industrialized countries. Although daily-life formaldehyde exposure level is practically impossible to induce cell death, most of mechanistic studies related to formaldehyde toxicity have been performed in cytotoxic concentrations enough to trigger cell death mechanism. Currently, toxicological mechanisms underlying the sub-cytotoxic exposure to formaldehyde are not clearly elucidated in skin cells. In this study, the genome-scale transcriptional analysis in normal human keratinocytes (NHKs) was performed to investigate cutaneous biological pathways associated with daily life formaldehyde exposure. We selected the 175 upregulated differentially expressed genes (DEGs) and 116 downregulated DEGs in NHKs treated with 200μM formaldehyde. In the Gene Ontology (GO) enrichment analysis of the 175 upregulated DEGs, the endoplasmic reticulum (ER) unfolded protein response (UPR) was identified as the most significant GO biological process in the formaldeyde-treated NHKs. Interestingly, the sub-cytotoxic formaldehyde affected NHKs to upregulate two enzymes important in the cellular transsulfuration pathway, cystathionine γ-lyase (CTH) and cystathionine-β-synthase (CBS). In the temporal expression analysis, the upregulation of the pro-inflammatory DEGs such as MMP1 and PTGS2 was detected earlier than that of CTH, CBS and other ER UPR genes. The metabolites of CTH and CBS, l-cystathionine and l-cysteine, attenuated the formaldehyde-induced upregulation of pro-inflammatory DEGs, MMP1, PTGS2, and CXCL8, suggesting that CTH and CBS play a role in the negative feedback regulation of formaldehyde-induced pro-inflammatory responses in NHKs. In this regard, the sub-cytotoxic formaldehyde-induced CBS and CTH may regulate inflammation fate decision to resolution by suppressing the early pro-inflammatory response.

Concentrations and exposure risks of some metals in facial cosmetics in Nigeria

The concentrations of nine metals (Cd, Pb, Ni, Cr, Co, Cu, Fe, Mn and Zn) were determined in lip sticks, lip glosses, lip balms, eye pencils, eyeliners, eye shadows, blushes, mascaras and face powders. The study was aimed at providing information on the risk associated with human exposure to metals in these facial cosmetic products. The concentrations of metals in the samples were measured by atomic absorption spectrometry after digestion with a mixture of nitric acid, hydrochloric acid and hydrogen peroxide. The mean concentrations of metals in these facial cosmetics ranged from 3.1 to 8.4 μg g^-1 Cd, 12-240 μg g^-1 Pb, 9.1-44 μg g^-1 Cr, 18-288 μg g^-1 Ni, 1.6-80 μg g^-1 Cu, 7.9-17 μg g^-1 Co, 2.3-28 mg g^-1 Fe, 12-230 μg g^-1 Mn, and from 18 to 320 μg g^-1 Zn. The concentrations of Ni, Cr and Co were above the suggested safe limit of 1 μg g^-1 for skin protection, while Cd and Pb were above the Canadian specified limits. The systemic exposure dosage (SED) values for these metals obtained from the use of these facial cosmetic products were below their respective provisional tolerable daily intake (PTDI)/or recommended daily intake (RDI) values. The margin of safety values obtained were greater than 100 which indicated that the concentrations of the metals investigated in these facial cosmetics do not present considerable risk to the users except in the case of face powders.

Positive lists of cosmetic ingredients: Analytical methodology for regulatory and safety controls - A review

Cosmetic products placed on the market and their ingredients, must be safe under reasonable conditions of use, in accordance to the current legislation. Therefore, regulated and allowed chemical substances must meet the regulatory criteria to be used as ingredients in cosmetics and personal care products, and adequate analytical methodology is needed to evaluate the degree of compliance. This article reviews the most recent methods (2005-2015) used for the extraction and the analytical determination of the ingredients included in the positive lists of the European Regulation of Cosmetic Products (EC 1223/2009): comprising colorants, preservatives and UV filters. It summarizes the analytical properties of the most relevant analytical methods along with the possibilities of fulfilment of the current regulatory issues. The cosmetic legislation is frequently being updated; consequently, the analytical methodology must be constantly revised and improved to meet safety requirements. The article highlights the most important advances in analytical methodology for cosmetics control, both in relation to the sample pretreatment and extraction and the different instrumental approaches developed to solve this challenge. Cosmetics are complex samples, and most of them require a sample pretreatment before analysis. In the last times, the research conducted covering this aspect, tended to the use of green extraction and microextraction techniques. Analytical methods were generally based on liquid chromatography with UV detection, and gas and liquid chromatographic techniques hyphenated with single or tandem mass spectrometry; but some interesting proposals based on electrophoresis have also been reported, together with some electroanalytical approaches. Regarding the number of ingredients considered for analytical control, single analyte methods have been proposed, although the most useful ones in the real life cosmetic analysis are the multianalyte approaches.

Probabilistic hazard assessment for skin sensitization potency by dose-response modeling using feature elimination instead of quantitative structure-activity relationships

Supervised learning methods promise to improve integrated testing strategies (ITS), but must be adjusted to handle high dimensionality and dose-response data. ITS approaches are currently fueled by the increasing mechanistic understanding of adverse outcome pathways (AOP) and the development of tests reflecting these mechanisms. Simple approaches to combine skin sensitization data sets, such as weight of evidence, fail due to problems in information redundancy and high dimensionality. The problem is further amplified when potency information (dose/response) of hazards would be estimated. Skin sensitization currently serves as the foster child for AOP and ITS development, as legislative pressures combined with a very good mechanistic understanding of contact dermatitis have led to test development and relatively large high-quality data sets. We curated such a data set and combined a recursive variable selection algorithm to evaluate the information available through in silico, in chemico and in vitro assays. Chemical similarity alone could not cluster chemicals' potency, and in vitro models consistently ranked high in recursive feature elimination. This allows reducing the number of tests included in an ITS. Next, we analyzed with a hidden Markov model that takes advantage of an intrinsic inter-relationship among the local lymph node assay classes, i.e. the monotonous connection between local lymph node assay and dose. The dose-informed random forest/hidden Markov model was superior to the dose-naive random forest model on all data sets. Although balanced accuracy improvement may seem small, this obscures the actual improvement in misclassifications as the dose-informed hidden Markov model strongly reduced " false-negatives" (i.e. extreme sensitizers as non-sensitizer) on all data sets.

Isothiazolinones in commercial products at Danish workplaces

BACKGROUND

In recent years, a steep increase in the frequency of occupational contact allergy to isothiazolinones has been reported from several European countries.

OBJECTIVE

To examine the extent and occurrence of isothiazolinones in different types of product at Danish workplaces.

METHODS

Seven different isothiazolinones were identified in the Dictionary of Contact Allergens: Chemical Structures, Sources, and References from Kanerva's Occupational Dermatitis. By use of the chemical names and Chemical Abstracts Service numbers for these chemicals, information on products registered in the Danish Product Register Database (PROBAS) was obtained.

RESULTS

All seven isothiazolinones were registered in PROBAS. The top three isothiazolinones registered were: benzisothiazolinone (BIT), registered in 985 products, methylisothiazolinone (MI), registered in 884 products, and methylchloroisothiazolinone (MCI)/MI, registered in 611 products. The concentration ranges were 0.01 ppm to 45% for BIT, 0.01 ppm to 10% for MI, and 0.01 ppm to 14.1% for MCI/MI. The most common product type was 'paint and varnish'; five of the seven isothiazolinones were registered in this type of product.

CONCLUSION

Isothiazolinones are present in multiple products registered for use at workplaces, and may occur in high concentrations.