Nickel allergy in a Danish population 25 years after the first nickel regulation

Allergens Responsible for Contact Allergy in Children From 2010 to 2024: A Systematic Review and Meta-Analysis

Contact allergy (CA) is a frequent condition in children; however, newer estimates of the prevalence of CA in children are lacking. Herein, we aim to provide an estimate of the prevalence of CA in children from 2010 to 2024. Two authors independently searched PubMed, Embase and Web of Science for studies reporting the prevalence of positive patch tests (PPTs) to allergens in populations including ≥ 100 children (< 18 years). Proportion meta-analyses were conducted to calculate the pooled prevalence estimates of CA in children. Seventeen studies comprising 11 593 children undergoing patch testing with 4176 (36%) PPTs were eligible for inclusion. The allergen with the highest prevalence was nickel (11.9% [95% confidence interval [CI], 8.6%-15.71%]), followed by cobalt (6.6% [95% CI, 4.2%-9.5%]), cocamidopropyl betaine (5.5% [95% CI, 3.1-8.7]), bacitracin (5.2% [95% CI, 1.2%-10.0%]), fragrance mix I (4.8% [95% CI, 2.9%-7.1%]) and methylisothiazolinone (4.3% [95% CI, 2.2%-7.2%]). Children with atopic dermatitis had higher rates of PPTs for cocamidopropyl betaine, propylene glycol, lanolin alcohol and carba mix. Across geographical areas, higher prevalences of several allergens were found in the United States compared to Europe, for example, for methylisothiazolinone. This meta-analysis confirmed that CA is frequent in children across geographical areas; however, differences in the frequency of top allergens depend on regulatory interventions, indicating their value.

Neutrophil infiltration in allergic contact dermatitis to nickel

Allergic contact dermatitis (ACD) is traditionally recognized as a T-cell-mediated delayed-type hypersensitivity reaction. However, many patients with ACD have been reported to experience rapid-onset ACD reactions within hours of re-exposure on skin areas previously exposed to the contact allergen. In this study, three nickel-allergic patients were patch tested for nickel twice at the same skin site over 21 days. The results demonstrated that neutrophils are rapidly recruited to the skin sites previously exposed to nickel, leading to the rapid onset of ACD. Considering that many patients with ACD are frequently re-exposed to contact allergens on the same skin areas in their daily lives, we propose that mechanisms involved in neutrophil recruitment could be potential targets for future ACD treatment.

Prenatal exposure to nickel and atopic dermatitis at age 3 years: a birth cohort study with cytokine profiles

BACKGROUND

Nickel, the fifth most common element on Earth, is the leading inducer of contact allergies in humans, with potent immunological effects. Nickel-induced contact allergies predominantly affect females. Maternal exposure to nickel has been associated with several developmental abnormalities. However, how a maternal nickel exposure affects the development of atopic diathesis and immune abnormalities in children has never been addressed.

OBJECTIVES

We aimed to determine whether maternal Ni exposure affects the development of atopic dermatitis and immune abnormalities in their children.

METHODS

Using a birth cohort study, we analysed 140 mother-child pairs recruited in 2012-2015 from central Taiwan. Maternal exposure to nickel was estimated using urinary nickel levels measured by inductively coupled plasma mass spectrometry (ICP-MS). The serum levels of 65 analytes and IgE in 3-year-old children were profiled with a multiplex ELISA. The correlation between the maternal urinary nickel concentration and serum analyte levels was assessed using Spearmen's correlation. Multivariant regression analysis was performed to evaluate the association between maternal urinary nickel levels and serum analyte concentrations in their children.

RESULTS

The geometric means of the maternal urinary nickel and the children's serum IgE levels were 2.27 μg/L and 69.71 IU/ml, respectively. The maternal nickel exposure was associated with increased serum levels of IL-1β, IL-2, TNF-α, and leukaemia inhibitory factor (LIF) but with decreased serum levels of matrix metalloproteinase-1 (MMP-1), IL-2R, and eotaxin-1 in the children. In addition, the development of childhood atopic dermatitis at 3 years old was significantly associated with the child's serum levels of IgE and IL-2R, but it was negatively associated with the maternal nickel exposure.

CONCLUSIONS

This is the first study showing the potential immunological effects of maternal nickel exposure in their children at an early developmental stage.

Nickel penetration into stratum corneum in FLG null carriers - a human experimental study

Background

The filaggrin gene (FLG) plays a role in skin diseases, with the skin barrier function being impaired in FLG null carriers. The role of FLG status in relation to nickel penetration into the skin remains unclear.

Objectives

To elucidate the association between FLG status and nickel penetration into stratum corneum (SC) in individuals without self‐reported history of nickel allergy.

Methods

Forty participants (23 FLG wt and 17 FLG null) were exposed to a nickel solution (80 μg/cm²) which was applied onto 2 × 2 cm on their left forearm. After 4 h, the area was tape‐stripped with 10 consecutive tapes. Nickel in each tape was quantified using inductively coupled plasma mass spectrometry.

Results

The average recovered nickel dose was 35%–48%. A tendency towards lower recovery was seen in FLG null carriers compared to FLG wt carriers, and lower recovery in those with history of skin and/or respiratory symptoms compared to those without such history. This was however not statistically significant.

Conclusion

FLG null carriers had less nickel recovered by tape strips compared with FLG wt carriers and, compared with individuals without a history of skin and/or respiratory symptoms, indicating higher nickel penetration into SC for FLG null carriers, but further studies are needed.

CD8+ tissue-resident memory T cells recruit neutrophils that are essential for flare-ups in contact dermatitis

BACKGROUND

Allergic contact dermatitis (ACD) is classically described as a delayed-type hypersensitivity reaction. However, patients often experience flare-ups characterized by itching erythema, edema, and often vesicles occurring within hours after re-exposure of previously sensitized skin to the specific contact allergen. Recent studies have indicated that skin-resident memory T (T_RM ) cells play a central role in ACD. However, the pathogenic role of T_RM cells in allergen-induced flare-ups is not known.

METHODS

By the use of various mouse models and cell depletion protocols, we investigated the role of epidermal T_RM cells in flare-up reactions to the experimental contact allergen 1-fluoro-2,4-dinitrobenzene. The inflammatory response was measured by changes in ear thickness, and the cellular composition in epidermis was determined by flow cytometry and confocal microscopy. Finally, adaptive transfer and inhibitors were used to determine the role of T_RM cells, neutrophils, and CXCL1/CXCL2 in the response.

RESULTS

We show that CD8⁺ T_RM cells initiate massive infiltration of neutrophils in the epidermis within 12 h after re-exposure to the contact allergen. Depletion of neutrophils before re-exposure to the allergen abrogated the flare-up reactions. Furthermore, we demonstrate that CD8⁺ T_RM cells mediate neutrophil recruitment by inducing CXCL1 and CXCL2 production in the skin, and that blockage of the C-X-C chemokine receptor type 1 and 2 inhibits flare-up reactions and neutrophil infiltration.

CONCLUSION

As the first, we show that epidermal CD8⁺ T_RM cells cause ACD flare-ups by rapid recruitment of neutrophils to the epidermis.

Nickel release from metal items in contact with skin: a comparison of methods and practical implications for regulation in Europe

Contact allergy to Nickel is the most prevalent contact allergy in western societies. This has led to regulation for metallic items that come into prolonged and direct contact with the skin, such as buttons on clothing, belt buckles, jewelry and watches. In Europe, the legal provision is based on a test in which there is a limit to the amount of nickel that may be released from the item to an artificial sweat solution (EN 1811). This test is costly and has reproducibility issues. The resulting undertesting of items placed on the market, leads to many nickel releasing non-compliant articles being available in spite of the regulations that are in place. In this study, the performance of the standard release test is compared to the performance of a rapid nickel spot test based on dimethylglyoxime (DMG-test). The data suggest that using the rapid DMG-test for compliance testing is sufficiently equivalent to the current gold standard of EN 1811. Previously published comparisons between the DMG-test and EN 1811 did not consider the effect of accelerated wear and corrosion testing according to EN 12472. This study shows that by applying EN 12472, the number of deviating results between the DMG-test and EN 1811 decreases significantly. Regarding consumer protection, it is necessary for wear and corrosion resistance to be considered.

Patch Test Results to European Baseline Series in Turkey: A Prospective and Multicenter Study

BACKGROUND

Patch testing with the European Baseline Series (EBS) is an essential diagnostic tool for the assessment of allergic contact dermatitis.

OBJECTIVE

The aims of the study were to describe the most common contact allergens identified with patch testing in Turkey and to establish the distribution of contact allergens among different regions in Turkey.

PATIENTS AND METHODS

Twelve centers consisting of tertiary health care institutions were included in the study. A total of 1169 patients were patch tested with the EBS from 2015 to 2017.

RESULTS

A total of 596 patients (51.0%) had 1 or more positive patch test reactions to the EBS. A total of 30.2% (n = 353) of those tested had clinical relevance. Contact sensitivity was more common in young patients. The most common 10 allergens were nickel sulfate (20.4%), followed by textile dye mix (8.6%), cobalt chloride (8.3%), potassium dichromate (8.0%), p-phenylenediamine base (4.5%), balsam of Peru (4.3%), methylchloroisothiazolinone/methylisothiazolinone (3.8%), thiuram mix (3.6%), fragrance mix I (3.0%), and methylisothiazolinone (2.9%).

CONCLUSIONS

This study provides a comprehensive profile of patch test results with the EBS in Turkey. An ongoing decrease in contact allergy to methylchloroisothiazolinone/methylisothiazolinone and methylisothiazolinone was observed. Textile dye mix and p-phenylenediamine are beginning to pose a new risk in Turkey.

Nickel release from metallic earrings: A survey of the Danish market and validation of the nickel spot test

BACKGROUND

Exposure to nickel-releasing ear-piercing jewellery may explain the persistently high prevalence of nickel allergy in Europe. While nickel release from earrings is regulated, field studies show that the regulation is not always respected. More knowledge is needed regarding the risk of piercing exposure including suitable screening methods.

OBJECTIVE

To examine the proportion of earrings on the Danish market that release more nickel than allowed, and to validate the use of the dimethylglyoxime (DMG) test as a screening tool.

METHODS

A total of 304 earrings were purchased and tested with the DMG test and X-ray fluorescence spectrometry. The level of nickel release was quantified in a selected subsample of 100 earrings by the European reference test EN 1811. The DMG spot test was validated against EN 1811 at different thresholds.

RESULTS

Excessive nickel release according to the European regulation was found in 45 (14.8%) tested earrings. The sensitivity of the DMG test decreased with reduced levels of nickel release (sensitivity of 45.2% at ≥0.2 μg/cm2 /week vs 61.1% at >0.5 μg/cm2 /week).

CONCLUSION

Excessive nickel release is common in earrings on the Danish market. Because of low sensitivity, the DMG test has limited use in screening of earrings for research but may still be used clinically.

Nickel Allergic Contact Dermatitis: Identification, Treatment, and Prevention

Nickel is a ubiquitous metal added to jewelry and metallic substances for its hardening properties and because it is inexpensive. Estimates suggest that at least 1.1 million children in the United States are sensitized to nickel. Nickel allergic contact dermatitis (Ni-ACD) is the most common cutaneous delayed-type hypersensitivity reaction worldwide. The incidence among children tested has almost quadrupled over the past 3 decades. The associated morbidities include itch, discomfort, school absence, and reduced quality of life. In adulthood, individuals with Ni-ACD may have severe disabling hand eczema. The increasing rate of Ni-ACD in children has been postulated to result from early and frequent exposure to metals with high amounts of nickel release (eg, as occurs with ear piercing or with products used daily in childhood such as toys, belt buckles, and electronics).To reduce exposure to metal sources with high nickel release by prolonged and direct contact with human skin, Denmark and the European Union legislated a directive several decades ago with the goal of reducing high nickel release and the incidence of Ni-ACD. Since then, there has been a global reduction in incidence of Ni-ACD in population-based studies of adults and studies of children and young adults being tested for allergic contact dermatitis. These data point to nickel exposure as a trigger for elicitation of Ni-ACD and, further, provide evidence that legislation can have a favorable effect on the economic and medical health of a population.This policy statement reviews the epidemiology, history, and appearances of Ni-ACD. Examples of sources of high nickel release are discussed to highlight how difficult it is to avoid this metal in modern daily lives. Treatments are outlined, and avoidance strategies are presented. Long-term epidemiological interventions are addressed. Advocacy for smarter nickel use is reviewed. The American Academy of Pediatrics supports US legislation that advances safety standards (as modeled by the European Union) that protect children from early and prolonged skin exposure to high-nickel-releasing items. Our final aim for this article is to aid the pediatric community in developing nickel-avoidance strategies on both individual and global levels.

Analysis of nickel distribution by synchrotron radiation X-ray fluorescence in nickel-induced early- and late-phase allergic contact dermatitis in Hartley guinea pigs

BACKGROUND

Nickel-induced allergic contact dermatitis (Ni-ACD) is a global health problem. More detailed knowledge on the skin uptake of haptens is required. This study aimed to investigate the penetration process and distribution of nickel in skin tissues with late phase and early phase of Ni-ACD to understand the mechanisms of metal allergy.

METHODS

Forty Hartley guinea pigs were divided into four groups according to the NiSO4 sensitizing concentration and the NiSO4 challenged concentration: the 5% NiSO4-group, 5% to 10% (sensitization-challenge; late phase group); 10% NiSO4-group, 10% to 10% (sensitization-challenge; early-phase group); and the positive and negative controls. Pathological biopsies were performed on each group. The depth profile of nickel element concentration in the skin of guinea pigs was detected by synchrotron radiation micro X-ray fluorescence spectroscopy (SR-μ-XRF) and micro X-ray absorption near-edge spectroscopy (μ-XANES).

RESULTS

In each section, the nickel element concentration in both the 5% NiSO4-group and 10% NiSO4-group was significantly higher than that in the negative control group. In the upper 300-μm section of skin for the early phase group, the nickel element concentration was significantly higher than that in the lower section of skin. In deeper sections (>200 μm) of skin, the concentration of nickel in the early phase group was approximately equal to that in the late phase group. The curve of the late phase group was flat, which means that the nickel element concentration was distributed uniformly by SR-μ-XRF. According to the XANES data for the 10% NiSO4 metal salt solution, structural changes occurred in the skin model sample, indicating that nickel was not present in the Ni aqueous ionic state but in the nickel-binding protein.

CONCLUSIONS

This study showed that the distribution of the nickel element concentration in ACD skin tissue was different between the early phase and late phase groups. The nickel element was not present in the Ni aqueous ionic state but bound with certain proteins to form a complex in the stratum corneum in ACD model tissue.

Recovery and characterization of nickel particles by chemical reduction method from wastes generated in electroless industry

The discarded solutions by the chemical nickel industry have high amounts of nickel, this is why they are considered hazardous wastes for the health and the environment. On the other side, Ni particles can have potential applications in the developing of magnetorheological fluids currently being used to improve the performance of mechanical devices. The present study raises the treatment of a residual effluent from a chemical nickel industry by applying a chemical precipitation which uses sodium hypophosphite as a reducer, and varying the order of the reagents involved in the conditioning of the reaction with respect to the reducer. The recovered solids were studied using different material characterization techniques to recognize the chemical composition (X-Ray Fluorescence, Inductively Coupled Plasma Mass Spectrometry), crystallinity and morphology (X-Ray Diffraction, Scanning Electron Microscope), surface charge and size distribution (Dynamic Light Scattering). By the chemical reduction treatment it was possible to decrease the amount of nickel in the residual between 97.25% and 99.50%, obtaining Ni particles that were then tested to be used in magnetic fluids. To this purpose a suspension was prepared by mixing the Ni particles with silicone oil in a constant solid/liquid ratio, and the rheological behavior of this suspension was evaluated as a function of the magnetic field and the deformation applied, revealing an interesting magnetorheological behavior.

Nickel dermatitis from earrings 15 years after EU directive implementation: a clinical-epidemiological study and a market survey in Rome, Italy

BACKGROUND

Nickel (Ni) dermatitis remains a highly prevalent allergic condition in Italy. There is a continuous need for clinical and epidemiological surveillance to evaluate whether or not European Ni Directive has been effective in contact allergy prevention.

OBJECTIVES

To assess the prevalence of Ni dermatitis among patch-tested patients and self-interviewed school students and to analyse Ni release from earlobe jewellery.

METHODS

Results of patch tests performed in 2006-2007, 2015-2016 and 2017-2018 were retrieved. A questionnaire was compiled by 315 secondary school students. Ni release from earring parts was analysed with the EN1811:2015 method.

RESULTS

A significant time trend of decreasing Ni positivity from 2006-2007 to 2017-2018 was observed both in the overall population (44.1% in 2006-2007, 33.0% in 2015-2016, 31.6% in 2017-2018, P < 0.0001) and in female patients (P < 0.0001). Conversely, change was not significant in males (P = 0.16). Decrease was significant for all age groups, except for those aged >60 years (P = 0.51). Among 242 students who reported earring use, 130 (54%) reported symptoms at earlobes, mostly associated with jewellery of materials other than gold and silver (59% of those with earlobe symptoms). Ni release exceeded the migration limit in 4/21 (20%) earring parts.

CONCLUSIONS

A high prevalence of Ni dermatitis and earlobe symptoms were found in Rome. A decreasing time trend was noted, with a significant decline in Ni sensitivity compared to the situation observed right after Ni Directive implementation. This most likely represents the consequence of reduced Ni content in earring parts, although a major care in the use of Ni-containing objects could contribute to explain these findings.

Contact Allergy: A Review of Current Problems from a Clinical Perspective

Contact allergy is common, affecting 27% of the general population in Europe. Original publications, including case reports, published since 2016 (inclusive) were identified with the aim of collating a full review of current problems in the field. To this end, a literature search employing methods of systematic reviewing was performed in the Medline^® and Web of Science™ databases on 28 January 2018, using the search terms (“contact sensitization” or “contact allergy”). Of 446 non-duplicate publications identified by above search, 147 were excluded based on scrutiny of title, abstract and key words. Of the remaining 299 examined in full text, 291 were deemed appropriate for inclusion, and main findings were summarised in topic sections. In conclusion, diverse sources of exposures to chemicals of widely-differing types and structures, continue to induce sensitisation in man and may result in allergic contact dermatitis. Many of the chemicals are “evergreen” but others are “newcomers”. Vigilance and proper investigation (patch testing) are required to detect and inform of the presence of these haptens to which our populations remain exposed.

Pathomechanisms of Contact Sensitization

Contact sensitization is the initial process involved in the development of an allergic reaction to xenobiotic environmental substances. Here, we briefly describe the differences between irritant and allergic contact dermatitis. Then, we highlight the essential steps involved in the development of an ACD reaction, i.e., the protein binding of haptens, genetic factors influencing the penetration of sensitizers into the skin, the different mechanisms driving the initial development of an inflammatory cytokine micromilieu enabling the full maturation of dendritic cells, the role of pre- and pro-haptens, antigen presentation and T cell activation via MHC and CD1 molecules, dendritic cell (DC) migration, and potential LC contribution as well as the different T cell subsets involved in ACD. In addition, we discuss the latest publications regarding factors that might influence the sensitizing potential such as repeated sensitizer application, penetration enhancers, humidity of the skin, microbiota, Tregs, and phthalates. Last but not least, we briefly touch upon novel targets for drug development that might serve as treatment options for ACD.