Epidemiology of nickel allergy

Retrospective Analysis of Outcomes after Stapedotomy with Implantation of a Self-Crimping Nitinol Stapes Prosthesis

OBJECTIVE: To review hearing results after implantation of a self-crimping stapes prosthesis.

STUDY DESIGN AND SETTING: Analysis of hearing results in patients implanted with a self-crimping stapes prosthesis at two academic hospitals from 2000 to 2004.

RESULTS: Seventy-nine ears were divided into short-term and intermediate follow-up groups. The mean postoperative air-bone gap (ABG), preoperative minus postoperative ABG, and preoperative minus postoperative bone conduction values were 5.7, 21.4, and 4.1 dB, respectively, for the short-term group, and 6.3, 22.3, and 4.7dB, respectively, for the intermediate group. The ABG was <10 dB in 88 percent of the short-term group and in 79 percent of the intermediate group.

CONCLUSIONS: The self-crimping Nitinol stapes prosthesis provides excellent short-term and intermediate postoperative hearing results, and may overcome the limitations of stapes prostheses requiring manual crimping.

SIGNIFICANCE: This paper provides evidence for the use of a self-crimping Nitinol stapes prosthesis, which may simplify hearing restoration surgery for stapes fixation.

Mechanical evaluation of quad-helix appliance made of low-nickel stainless steel wire

OBJECTIVE

The objective of this study was to test the hypothesis that there is no difference between stainless steel and low-nickel stainless steel wires as regards mechanical behavior. Force, resilience, and elastic modulus produced by Quad-helix appliances made of 0.032-inch and 0.036-inch wires were evaluated.

METHODS

Sixty Quad-helix appliances were made, thirty for each type of alloy, being fifteen for each wire thickness, 0.032-in and 0.036-in. All the archwires were submitted to mechanical compression test using an EMIC DL-10000 machine simulating activations of 4, 6, 9, and 12 mm. Analysis of variance (ANOVA) with multiple comparisons and Tukey's test were used (p < 0.05) to assess force, resilience, and elastic modulus.

RESULTS

Statistically significant difference in the forces generated, resilience and elastic modulus were found between the 0.032-in and 0.036-in thicknesses (p < 0.05).

CONCLUSIONS

Appliances made of low-nickel stainless steel alloy had force, resilience, and elastic modulus similar to those made of stainless steel alloy.

Citotoxicidade de soldas elétricas a ponto: estudo in vitro

OBJETIVO: o processo de solda envolve íons metálicos capazes de provocar lise celular. Diante disso, o objetivo deste estudo foi testar a hipótese de que existe citotoxicidade entre diferentes tipos de ligas (CrNi, TMA, NiTi) utilizadas em Ortodontia, submetidas à solda elétrica a ponto. MÉTODOS: três tipos de ligas foram avaliados neste estudo. Foram confeccionados 36 corpos de prova, 6 para cada combinação entre os fios, divididos em 6 grupos - grupo AA (aço com aço), grupo AT (aço com TMA), grupo AN (aço com NiTi), grupo TT (TMA com TMA), grupo TN (TMA com NiTi) e grupo NN (NiTi com NiTi) - que foram submetidos à solda a ponto para avaliação quanto ao possível efeito citotóxico nos tecidos bucais. Previamente, os corpos de prova foram limpos com álcool isopropílico e esterilizados em luz ultravioleta. O ensaio de citotoxicidade foi realizado utilizando-se cultura de células (linhagem L929, fibroblastos de camundongos), submetida ao teste para células viáveis em vermelho neutro ("dye-uptake") no tempo de 24h. A análise de variância e comparação múltipla (ANOVA) e teste de Tukey foram utilizados (p< 0,05). RESULTADOS: os resultados demonstraram que não houve diferença estatisticamente significativa entre os grupos experimentais (P> 0,05). Foi observada maior viabilidade celular no grupo TT, seguido dos grupos AT, TN, AA, NA e NN. CONCLUSÃO: pôde-se evidenciar que solda em fios de liga de NiTi causaram maior quantidade de lise celular. Soldas elétricas a ponto demonstraram pequena capacidade de causar lise celular.

A severe reaction to ni-containing orthodontic appliances

Exposure to nickel-containing orthodontic appliances may cause intra- or extraoral allergic reactions. Nickel is the most typical antigen implicated in causing allergic contact dermatitis, which is a Type IV delayed hypersensitivity immune response. This report presents an unusual reaction to nickel during the orthodontic treatment of an adult female patient. The patient had no previous history of allergy and had been wearing fixed metal upper appliances while in orthodontic treatment to assist the eruption of her impacted teeth. The adverse hypersensitivity reactions appeared only after the surgical exposure and included severe signs of eczematic and urticarial reactions of the face with redness, irritation, itching, eczema, soreness, fissuring, and desquamation as well as intraoral diffuse red zones. Diagnostic patch testing performed by the allergist revealed sensitization to nickel (++++ score). Treatment was achieved with nickel-free appliances.

Cellular, humoral, and histopathologic analysis in rats implanted with orthodontic nickel brackets

OBJECTIVE

To determine the immune response related to nickel and nickel-free orthodontic appliances using cellular (total and differential leukocytes) and humoral (IgA) quantification.

MATERIALS AND METHODS

Thirty-five Wister rats were randomly distributed into three groups (A, B, and C). In the A group, the animals were subdivided into three subgroups (A1: control, without brackets; A2: nickel-free brackets; and A3: nickel brackets) with seven animals in each group; the animals were sacrificed after 14 days. Groups B and C received only nickel brackets and were kept for 14 days. After this period, the implants were removed and the rats were sacrificed. In group B, the animals were sacrificed 2 days after the appliance removal (16 days in total); and in group C, the animals were sacrificed 7 days after the brackets removal (21 days in total). Total and differential leukocyte number, IgA quantification and histopathologic analysis were done. Histopathologic analysis of subcutaneous tissue related to the orthodontic brackets was done as well.

RESULTS

There were significant differences between the number of leukocytes for the nickel-implanted animals and the nickel-free and control groups after 14 days of implantation (P < .05). However, there was no significant difference among groups A1, A2, and A3 for the differential number of leukocytes and for the IgA quantification, except for the number of monocytes, which was three times higher in the nickel group (A3). The histopathologic findings did not show differences between groups.

CONCLUSIONS

Nickel did not promote significant adverse biological effects.

Corrosion of stainless steel sternal wire after long-term implantation

A variety of metallic components have been used in medical devices where lifelong durability and physical strength are demanded. To investigate the in vivo changes of implanted metallic medical devices in humans, stainless steel sternal wires removed from patients were evaluated. Stainless steel (316L) sternal wires removed from four patients after 10, 13, 22, and 30 years of implantation were evaluated using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Macroscopically, the removed specimens maintained their metallic luster and color. Under SEM, small holes were observed sporadically at 10 years and they tended to connect in the drawing direction. The longer the implanted duration, the more numerous and deeper were the crevices observed. By EDS, sulfur, phosphorus, and calcium were identified in all areas at 10 years, in addition to the component elements of stainless steel, comprising iron, chromium, nickel, and manganese. Corrosion products observed at 30 years were identified as calcium phosphate. In conclusion, stainless steel sternal wires develop corroded pores that grow larger and deeper with time after implantation; however, the pores remain shallow even after decades of implantation and they may not be a cause of mechanical failure. An amount of metal ions equivalent to the corroded volume must have been released into the human body, but the effect of these metal ions on the body is not apparent.

Dermal nickel exposure associated with coin handling and in various occupational settings: assessment using a newly developed finger immersion method

BACKGROUND

The role of nickel in causing hand dermatitis in some occupations has been difficult to assess due to problems with reliable measurement of the exposure to nickel in the workplace and lack of a definitive threshold for nickel allergic contact dermatitis. It is not uncommon to find nickel allergy on patch testing but it is difficult to determine whether this is of relevance to occupational nickel exposure or simply a reflection of past exposure to nickel-plated jewellery or other nonoccupational nickel exposure.

OBJECTIVES

To devise a simple and reproducible method to quantify the amount of nickel on the skin and to apply the technique to measure dermal nickel exposure in various occupational settings.

METHODS

A rapid and simple sampling procedure was developed for determination of nickel on the skin of workers potentially exposed to nickel by exposing individuals to nickel-releasing coins and measuring exposure by immersing the exposed thumbs and index fingers directly into graduated sample tubes containing ultrapure water and aqueous nickel extracts. The solutions were analysed by inductively coupled plasma-optical emission spectrometry after stabilization with nitric acid. The method shows advantages over alternatives such as wipe testing and tape stripping in terms of extraction efficiency, speed and ease of operation in the field. A pilot survey of dermal nickel exposure for workers in several occupational settings was conducted.

RESULTS

The study suggested that a 'normal' level of nickel on the skin is <10 ng cm(-2). Coin handling induced an appreciable increase in the amount of nickel on the skin within 2 min. Experiments indicated a linear relationship between coin handling (exposure time) and measured dermal nickel levels following standardized coin handling. A pilot survey, conducted among cashiers, shop assistants, bar staff, hairdressers and workers in the nickel industry revealed dermal nickel concentrations ranging from <0.9 to 7160 ng cm(-2). The levels of nickel on the skin of cashiers, shop assistants, bar staff and hairdressers were below the threshold level for water-soluble ionic nickel for occluded exposure at which 10% of nickel-allergic subjects react (0.01% or 100 parts per million, equivalent to 530 ng cm(-2)) and the five-times higher threshold for unoccluded exposure (500 parts per million). The levels in some nickel platers and nickel refinery workers approached or exceeded these levels. However, few cases of nickel dermatitis are observed in plating and refinery facilities, perhaps due to immune tolerance, self-selection or, for refinery workers, exposure to water-insoluble rather than water-soluble nickel compounds. The elicitation threshold for water-soluble nickel compounds cannot be compared directly with dermal exposure to water-insoluble nickel compounds as the latter release a significantly lesser amount of nickel ions.

CONCLUSIONS

We describe a reproducible, simple and rapid procedure for the assessment of nickel levels in occupationally exposed individuals.

Characterization of nickel-induced allergic contact stomatitis associated with fixed orthodontic appliances

INTRODUCTION

In some orthodontic patients, an oral inflammatory response is induced by corrosion of orthodontic appliances and subsequent nickel release. This inflammatory response is manifested as stomatitis (nickel-induced allergic contact stomatitis [NiACS]). The etiology and diagnosis of NiACS are difficult to determine. The purpose of this retrospective analysis was to investigate the roles of age, sex, previous allergic history, and time of exposure to fixed orthodontic appliances in the etiopathogeny of NiACS.

METHODS

Forty-four orthodontic patients (range, 10-44 years) were divided into 2 groups, depending on their NiACS clinical manifestations.

RESULTS

Young patients, especially females with a history of allergic reactions, had a greater predisposition to NiACS clinical manifestations; time of exposure to orthodontic appliances was not a significant factor.

CONCLUSIONS

A previous allergic reaction should be considered a predictive factor of NiACS clinical manifestations and should be noted in the patient's medical history.

Nickel Exposure and its Effects

The aim of the study was to determine the nickel concentrations of soil and plant specimens taken from a rural area exposed to cement factory emissions and also to determine the blood concentrations and sensitivity conditions observed in humans residing in this rural area. The study was carried out in Cukurhisar, a town in Eskişehir-Turkey, between May 2000 and March 2001. Beside the 108 soil (36 for control) and plant specimens, which were taken from 8 directions from the cement factory, blood samples of the individuals residing in this area were taken from 258 subjects (258 for control) following a physical examination, and patch tests were also applied. The nickel concentrations of the soil and plant specimens taken from different places in different directions of the factory were higher than in the control areas. The physical examination of subjects did not reveal results different from those of the control group except for the diagnosis of contact dermatitis. The analyses of venous blood samples showed that nickel concentrations were found to be within the reference values given for both groups, but higher in the subjects (p < 0.001). According to the results of patch tests, sensitivity to nickel was found to be more frequent for the subject group than the control group (p < 0.05). According to these results, clinical tools revealed no toxic effects for the subjects, except contact dermatitis. However, sensitivity to patch tests showed that this subject group has been affected compared to the control group and that this effect increased with age.

Proposal for a risk assessment methodology for skin sensitization based on sensitization potency data

In this paper, we propose a quantitative risk assessment methodology for skin sensitization aiming at the derivation of 'safe' exposure levels for sensitizing chemicals, used e.g., as ingredients in consumer products. Given the limited number of sensitizers tested in human sensitization tests, such as the human repeat-insult patch test (HRIPT) or the human maximization test (HMT), we used EC3 values from the local lymph node assay (LLNA) in mice because they provide the best quantitative measure of the skin sensitizing potency of a chemical. A comparison of LLNA EC3 values with HRIPT and HMT LOEL, and NOEL values was carried out and revealed that the EC3, expressed as area dose, can be used as a surrogate value for the human NOEL in risk assessment. The uncertainty/extrapolation factor approach was used to derive (a) an 'acceptable non-sensitizing area dose' (ANSAD) to protect non-allergic individuals against skin sensitization and (b) an 'acceptable non-eliciting area dose' (ANEAD) to protect allergic individuals against elicitation of allergic contact dermatitis. For ANSAD derivation, interspecies, intraspecies and time extrapolation factors are applied to the LLNA EC3. For ANEAD derivation, additional application of a variable sensitization-elicitation extrapolation factor is proposed. Values for extrapolation factors are derived and discussed, the proposed methodology is applied to the sensitizers methylchloroisothiazolinone/methylisothiazolinone, cinnamic aldehyde and nickel and results are compared to published risk assessments.

Occupational contact dermatitis to nickel: experience of the British dermatologists (EPIDERM) and occupational physicians (OPRA) surveillance schemes

AIMS

To examine, from occupational surveillance reporting data, whether scheme reporters considered nickel exposure to play a role in occupational contact dermatitis (OCD) in the UK.

METHODS

Data on occupational skin disease in the UK are collected by two occupational disease surveillance schemes, EPIDERM and OPRA. Cases of OCD believed to have relevant nickel exposure reported to EPIDERM or OPRA from February 1993 to January 1999 were studied.

RESULTS

An estimate of 1190 cases of occupational contact dermatitis thought to have relevant nickel exposure (12% of total estimated OCD) was derived from reports by dermatologists, an average of 198 per year. The highest incidence rates were seen in hairdressers (23.9/100 000 workers/year), bar staff (4.7), chefs and cooks (4.4), retail cash and checkout operators (2.8), and catering assistants (2.5). From May 1994 to January 1999, 158 cases of nickel associated dermatitis (1.9% of total OCD cases) were estimated; the most frequently reported occupations were electronic assemblers, nurses, sales assistants, and general assemblers. From July 1997 to January 1999, 547 positive patch tests to nickel were reported; in 195 cases (36%), nickel was felt to be a relevant occupational allergen (for example, coin handling). In hairdressers, nurses, cooks, and beauticians, nickel was usually considered, if relevant at all, to be only one of several causes of dermatitis.

CONCLUSIONS

Up to 12% of total estimated cases of OCD were thought to be due in part to nickel. Results suggest that nickel hypersensitivity is one of several contributors to OCD in subjects with multiple occupational exposures. Coin handling may be a source of OCD to nickel.

Tolerance to nickel: oral nickel administration induces a high frequency of anergic T cells with persistent suppressor activity

We adapted our mouse model of allergic contact hypersensitivity to nickel for the study of tolerance. Sensitization in this model is achieved by the administration of nickel ions with H(2)O(2); nickel ions alone are unable to prime naive T cells, but can restimulate primed ones. A 4-wk course of oral or i.p. administration of 10 mM NiCl(2) to naive mice induced tolerance, preventing the induction of hypersensitivity for at least 20 wk; long term desensitization of nickel-sensitized mice, however, required continuous NiCl(2) administration. When splenic T cells of orally tolerized donors, even after a treatment-free interval of 20 wk, were transferred to naive recipients, as with lymph node cells (LNC), they specifically prevented sensitization of the recipients. The LNC of such donors were anergic, because upon in vivo sensitization with NiCl(2) in H(2)O(2) and in vitro restimulation with NiCl(2), they failed to show the enhanced proliferation and IL-2 production as seen with LNC of mice not tolerized before sensitization. As few as 10(2) bulk T cells, consisting of both CD4(+) and CD8(+) cells, were able to specifically transfer tolerance to nickel. A hypothesis is provided to account for this extraordinarily high frequency of nickel-reactive, suppressive T cells; it takes into account that nickel ions fail to act as classical haptens, but form versatile, unstable metal-protein and metal-peptide complexes. Furthermore, a powerful amplification mechanism, such as infectious tolerance, must operate which allows but a few donor T cells to tolerize the recipient.

Prevalence of nickel allergy among Finnish university students in 1995

Nickel allergy was studied in a sample of 1st-year university students starting their studies in 1995. A total of 296 subjects (72%) of 413 invited participated in the clinical examination, and 284, 96 male and 188 female, were patch tested (69%). A history of nickel sensitization was enquired for. Prick tests and serum specific IgE levels were determined. Occurrence of atopic dermatitis, hand eczema, and current exposure to metals were recorded. Nickel allergy was encountered in 39% of all female students, in 42% of females with pierced skin, and in 14% of females without pierced skin. The corresponding figures for males were 3%, 7% and 3%. In the multiple regression analysis, the risk factors for nickel allergy were female sex (OR 8.1, p<0.01), current metal exposure at examination (OR 4.1, p<0.01) and skin piercing (OR 3.6, p<0.05). Positive prick tests or elevated IgE levels to common allergens were not significantly associated with nickel allergy. In female students, the prevalence of nickel allergy has increased from 13% in 1986 to 39%. The prevalence among males has remained low at 3%. The results indicate that, in addition to skin piercing, current metal contacts are important risk factors for nickel allergy. This finding gives support to the EU Nickel Directive.

Nickel allergy and its relationship with local nickel pollution, ear piercing, and atopic dermatitis: a population-based study from Norway

BACKGROUND

The north-Norwegian population of Sør-Varanger lives close to 2 Russian nickel smelters.

OBJECTIVE

We studied the importance of the local nickel pollution, as well as ear piercing and atopic dermatitis, on the prevalence of nickel allergy in Sør-Varanger.

METHODS

We patch-tested 1767 adults who were randomly selected from 2 different cross-sectional studies; in Sør-Varanger and the reference city of Tromsø, which has no nickel-polluting industry.

RESULTS

Nickel allergy was diagnosed in 27.5% and 31.1% of the women in Sør-Varanger and Tromsø, respectively, and in 5.1% and 5.0% of the men. In women, ear piercing was a strong risk factor (relative risk = 3.30; 95% confidence interval = 2.01 to 5.43). A history of atopic dermatitis was not associated with nickel sensitization. We found no increased risk of nickel allergy in Sør-Varanger compared with Tromsø in adjusted multivariate analyses.

CONCLUSION

The high prevalence of nickel allergy found in Sør-Varanger could not be attributed to pollution from the nearby nickel industry.

Is it possible to improve the prognosis in nickel contact dermatitis?

A questionnaire was sent to 143 patients who had shown a positive patch test reaction to nickel sulfate more than 10 years earlier. 91 patients returned the questionnaire, revealing that after the testing, 73 had suffered from dermatitis, 61 especially from hand dermatitis. 37 of these patients were clinically examined and patch tested with standard series and in addition, 12 patients were tested with nickel sulfate and nickel chloride with different occlusion times. At the clinic visit, 23 patients had dermatitis, 16 hand dermatitis, and 11 were symptom-free. 26 of the patients had metal items close to their skin and 21 of them had current dermatitis, 14 hand dermatitis. Of the 11 patients who had no metal exposure, 9 were symptom-free. The association of dermatitis with exposure to metal objects was statistically significant (p < 0.001). Those patients who had current dermatitis had also developed multiple allergies and reacted to nickel with shorter application times in patch tests, as compared to those who were symptom-free. It seemed possible that the prognosis for nickel dermatitis could be improved if nickel-allergic patients would strictly avoid metal contact, especially in clothing and jewelry.

Nickel dermatitis: how much nickel is safe?

The Nickel Directive will become law in the countries of the European Union in 1996. This directive states that the concentration of nickel in post assemblies (used after ear piercing) may not exceed 0.05%, that products which come into direct and prolonged contact with the skin, e.g. earrings, watchstraps or zippers, may not release greater than 0.5 microgram/cm2/week, and that nickel release from coated products will not exceed this level after 2 years of normal use. The data relating to the threshold for reacting to nickel and the levels of nickel release from nickel-containing objects, are considered in this review. Although the level of 0.5 microgram/cm2/week is one below which a minority of nickel-allergic subjects will react, it is not safe in every nickel-sensitive individual. This level of nickel release is currently exceeded by many nickel-containing alloys and jewelery items that are made from high-sulfur stainless steel, and manufacturers are going to have to change the composition of jewelery to comply with the directive.

Nickel allergy in adolescents in relation to orthodontic treatment and piercing of ears

The aim of this study was to investigate the frequency of nickel hypersensitivity in adolescents in relation to sex, onset, duration and type of orthodontic treatment, and the age at which ears were pierced. The subjects were 700 Finnish adolescents, from 14 to 18 years of age, of which 476 (68%) had a history of orthodontic treatment with metallic appliances. The study consisted of patch-testing for a nickel allergy and a patient history obtained by a questionnaire and from patient record. The frequency of nickel sensitization in the whole group was 19%. Nickel allergy was significantly more often found in girls (30%) than in boys (3%) and in subjects with pierced ears (31%) than in those with no piercing of ears (2%). Orthodontic treatment did not seem to affect the prevalence of nickel sensitization. None of the girls who were treated with fixed orthodontic appliances before ear piercing showed hypersensitivity to nickel, whereas 35% of the girls who had experienced ear piercing before the onset of orthodontic treatment were sensitized to nickel. The results suggest that orthodontic treatment does not seem to increase the risk for nickel hypersensitivity. Rather, the data suggests that treatment with nickel-containing metallic orthodontic appliances before sensitization to nickel (ear piercing) may have reduced the frequency of nickel hypersensitivity.

Immunocompetent cells adjacent to stainless steel and titanium miniplates and screws

Subepithelial soft tissue and bone obtained from the implant bed in the vicinity of stainless steel and titanium miniplates and screws were evaluated with respect to the presence of immunocompetent cells. The study included tissue specimens from 19 patients, in whom the implants (14 stainless steel and 5 titanium) had been in situ for more than 6 months. The ABC (avidin-biotin-complex) immunoperoxidase staining technique using monoclonal antibodies defining T lymphocytes (CD3+), macrophages (CD11c+) and Class II MHC (HLA-DR) was performed on EDTA demineralized, frozen bone tissue, and on fresh frozen soft tissue specimens. The results showed scattered T lymphocyte clusters, small numbers of macrophages and abundant expression of HLA-DR in the soft tissue adjacent to both stainless steel and titanium implants. There was no substantial difference in tissue reactions between implants of the two materials. The demineralized bone sections disclosed presence of immunocompetent cells in the connective tissue lining the periphery of the screw holes. Metal particles were seen in both the soft tissue and the bone specimens. We conclude that a mild tissue reaction takes place in the vicinity of miniplates and screws of stainless steel and titanium, and that the intensity of the reaction indicates that the implants are well tolerated by the host tissue.

Proliferation of nickel-sensitive human lymphocytes by corrosion products of orthodontic appliances

Lymphocyte transformation tests were performed on peripheral blood taken from individuals with a history of contact dermatitis who also presented with a positive patch test to nickel sulphate, and from individuals with no history of contact dermatitis. The results implied that nickel leached out from metallic orthodontic appliances in sufficient amounts and of a chemical nature adequate to stimulate proliferation of lymphocytes from some of the nickel-sensitive subjects.

Immune response to nickel and some clinical observations after stainless steel miniplate osteosynthesis

Fifteen patients undergoing internal fixation for mandibular fractures were examined for delayed type hypersensitivity (DTH) reaction to nickel before and after implantation of stainless steel miniplates. A lymphocyte transformation test (LTT) was used to measure the immune response before implantation and at removal of plates and screws. The clinical complications during fracture healing were also recorded. The results show that the in vitro LTT may be useful in nickel hypersensitivity testing. A significant increase in lymphocyte transformation was found as a response to nickel stimulation (0.5 microgram Ni/ml) at removal of the implants. We conclude that, despite an increase in LTT after stainless steel implantation, no adverse clinical complications related to DTH could be recorded after short-time observation.

Nickel hypersensitivity in the orthodontic patient

Nickel is one of the most common causes of allergic contact dermatitis and produces more allergic reactions than all other metals combined. Currently, several brands of orthodontic wires are made of nickel titanium alloy and potentially have a high enough nickel content to provoke manifestations of allergic reactions in the oral cavity. The objectives of this study were (1) to determine if standard orthodontic therapy can sensitize patients to nickel, and (2) to assess gingival response to nickel-containing orthodontic appliances in patients who are nickel sensitive before treatment. Nickel sensitivity patch tests were conducted to confirm hypersensitivity to nickel. Twenty-nine patients from the Division of Orthodontics, Albert Einstein/Montefiore Medical Center were tested, ranging in age from 12 to 48 years. Of the 29 patients, there were 18 female and 11 males. Five of the patients had a positive nickel patch test, a rate of 18.5%. The five patients that tested positive were all female, meaning that the overall rate for females was 27.7% (5:18). The five female patients sensitive to nickel were followed monthly by intraoral photos and gingival and plaque index scores. The remaining patients began routine orthodontic therapy and were retested 3 months into treatment to see whether sensitization occurred. Two patients converted from an initial negative patch test to a positive test. There may be a risk of sensitizing patients to nickel with long-term exposure to nickel-containing appliances as occurs in routine orthodontic therapy.

Nickel, cobalt and chromium in consumer products: a role in allergic contact dermatitis?

In spite of the improved awareness of the potential for nickel, cobalt and chromium to cause skin allergy, the incidence of sensitization to them is generally on the increase, especially for nickel. We review data from the literature and industry on transition metal contamination of consumer products and assess the hazard to man. Consumer products are defined as personal care items and detergent/cleaning products used regularly in domestic work. The analytical data demonstrate that consumer products are a relatively minor source of contact with nickel, cobalt or chromium. The traces found in consumer products will not be the primary cause of sensitization to these metals: levels will be too low and exposure too brief. A person sensitized to these metals has many other more significant sources of daily contact such as earrings, jewelry and metal objects. It is therefore necessary to focus on decreasing the high exposure to these transition metals from other sources rather than on possible trace amounts found in consumer products. Current good manufacturing practice ensures that trace nickel, cobalt and chromium concentrations in consumer products are less than 5 ppm of each metal. It is recommended that this be accepted as a standard for maximum concentrations and that the target should be to achieve concentrations as low as 1 ppm.

Metal release from arch bars used in maxillofacial surgery. An in vitro study

Surgical arch bars (splints) are used in maxillofacial surgery as an aid to intermaxillary fixation procedures. Two different types of stainless steel arch bars, a solid bar and a silver-brazed bar, were studied with regard to metal release in vitro. Arch bars were ligated to jaw models and immersed in 0.9% saline solution. The electrolyte was analyzed for Ni, Cr, Fe, Cu, Zn, and Cd by atomic absorption spectrophotometry on days 3, 10, and 28. The amounts of metal released from the brazed arch bar were 140-600 times higher than those released from the solid arch bar. Clinical implications are suggested.

Nickel sensitivity: the influence of ear piercing and atopy

In a group of 612 consecutive patients undergoing routine patch tests for suspected allergic contact dermatitis, more than four-fifths of the 364 women had had their ears pierced, over half gave a history of cutaneous reactions to metallic jewelery and almost one-third were sensitive to nickel. The increase in the frequency of nickel sensitivity in women with pierced ears compared to those with unpierced ears was highly significant (P less than 0.001). In men, nickel sensitivity was much less frequent; occupational factors were often implicated and few cases were related to ear piercing. Jewelery dermatitis was more frequent in atopic than non-atopic women but atopy did not appear to influence the propensity for developing nickel sensitivity in either sex. Ear piercing seems to induce nickel allergy which may result in lifelong morbidity and difficulty in employment. Jewelery suppliers should be encouraged to provide nickel-free earrings to reduce the frequency of this apparently avoidable problem.

Metal carcinogenesis: mechanistic implications

Cancer epidemiology has identified several metal compounds as human carcinogens. Recent evidence suggests that carcinogenic metals induce genotoxicity in a multiplicity of ways, either alone or by enhancing the effects of other agents. This review summarizes current information on the genotoxicity of arsenic, chromium, nickel, beryllium and cadmium compounds and their possible roles in carcinogenesis. Each of these metals is distinct in its primary modes of action; yet there are several mechanisms induced by more than one metal, including: the induction of cellular immunity and oxidative stress, the inhibition of DNA metabolism and repair and the formation of DNA- and/or protein-crosslinks.

Skin sensitization--a critical review of predictive test methods in animals and man

With the exception of the Draize Test, the guinea-pig test methods currently accepted by regulatory authorities worldwide are well able to predict the potential of a material to cause skin sensitization. Nevertheless, (a) some methods are more sensitive than others (e.g. adjuvant tests are generally more sensitive than non-adjuvant tests); (b) methods cannot be sufficiently standardized to give full reproducibility of results between laboratories; and (c) most methods are based on subjective visual grading of skin reactions--difficulties thus arise when testing coloured or irritant materials. Laboratories must be able to show the sensitivity of the method(s) they use by demonstrating that positive reactions occur with mild/moderate contact allergens rather than the strong/extreme sensitizers currently recommended in certain guidelines, specifically in the EEC Test Method. The sensitivity of the adjuvant tests is such that it is possible to halve the minimum number of animals required by present regulatory guidelines without compromising the capacity of the tests to detect weak/mild sensitizers. A similar review has not yet been made for non-adjuvant tests. Alternative test methods, including some recently developed mouse models, offer several advantages, including more objective endpoints. These tests have not been extensively validated and this precludes their use at present for regulatory purposes other than to confirm the sensitization potential of a material. Two new test methods using mice, the Mouse Ear-swelling Test and the Local Lymph Node Assay, appear promising. They should undergo rigorous interlaboratory testing to determine their sensitivity and specificity. In vitro methods do not represent a viable alternative in the foreseeable future. An approach using quantitative structure-activity relationships is the most likely route to a non-animal model, but this will require considerable research, development and validation. Human sensitization tests have generally not been used for the classification of substances as non-sensitizers. This is because of an absence of internationally agreed test protocols, the lack of positive controls and because the methods for establishing the sensitivity of human tests are less developed than for animal tests. Nevertheless, for products for which direct human contact is intended, predictive tests in human volunteers can be considered. The EEC Directive for the Classification, Packaging and Labelling of Dangerous Substances provides a reasonable approach to the evaluation of skin sensitizers.(ABSTRACT TRUNCATED AT 400 WORDS)

The nickel content of certain commercially available metallic patch test materials and its relevance in nickel-sensitive subjects

The nickel contamination of the metallic patch test substances from 3 commercial sources was estimated by atomic absorption spectrophotometry. Contamination was generally greatest in the cobalt patch test substances. To determine whether the levels of contamination encountered were sufficient to produce a false positive patch test, 20 nickel-sensitive patients were patch tested to various concentrations of free elemental nickel in aqueous solution. The level of nickel contamination was less than that required to produce a false positive patch test in our patients, but was at a level which could produce false positive reactions in subjects highly sensitive to nickel.

The prognosis of contact dermatitis

This article reviews the prognosis of contact dermatitis, particularly of occupational contact dermatitis. Most studies document a poor prognosis for occupational and nonoccupational contact dermatitis. The prognoses of occupational and nonoccupational contact dermatitis, irritant contact dermatitis, and allergic contact dermatitis are similar. Only a minority of studies on the prognosis of occupational contact dermatitis have found that a job change by the affected worker leads to clearing of the dermatitis. Dermatologic and nondermatologic factors associated with a poor prognosis are discussed.

Cutaneous nickel sensitivity in Toronto, Canada

Patch tests were administered to 1074 subjects with suspected contact dermatitis by the method recommended by the International Contact Dermatitis Research Group. Of 629 subjects tested with 5% nickel sulfate in petrolatum, 10.5% had positive reactions (males, 5.1%; females, 16.7%). Of 447 subjects tested with 2.5% nickel sulfate in petrolatum, 11.9% reacted (males, 7.7%; females, 16.9%). In 447 subjects in whom the relationship between clinical findings and the patch test response was evaluated (i.e., relevance), more than 90% of the responses could be related to a past or present problem with contact dermatitis. The sites of involvement were not different between nickel-sensitive subjects and the overall population tested, except in the case of foot involvement, which was underrepresented in the nickel-sensitive group. Patients who had positive responses to nickel reacted more frequently to marginal irritants such as formaldehyde and benzoyl peroxide. This finding may suggest a reduction in the irritancy threshold in nickel-sensitive subjects. In most instances, domestic rather than occupational exposure was thought to account for the induction of nickel allergy.

Nickel sensitivity and the course of atopic dermatitis in adulthood

The course of dermatitis was followed in nickel-sensitive and nickel-negative atopic and non-atopic patients. Manifest dermatitis was seen in 70% of the nickel-allergic and in 64% of the nickel-negative female atopic dermatitis (AD) patients. Those atopic subjects who had minor symptoms in their teens suffered more from dermatitis if they had developed nickel allergy (p less than 0.025). Hands and the head region were the most common sites for current dermatitis in both groups.

Sternal wire-induced persistent chest pain: a possible hypersensitivity reaction

Persistent chest pain has been reported to be a relatively common complaint after operations through a median sternotomy approach. We report a case that we believe represents a sternal pain syndrome resulting from sensitivity to nickel in the stainless steel sternal wires. In view of the high incidence of nickel sensitivity in the general population, we question whether such sensitivity may be involved in similar poststernotomy pain syndromes when any other clear-cut pathophysiological process is not apparent.

Toxicity and carcinogenicity of nickel compounds

The toxicity and carcinogenicity of nickel compounds are considered in three broad categories: (1) systemic toxicology, (2) molecular toxicology, and (3) carcinogenicity. The systemic toxicity of nickel compounds is examined based upon human and animal studies. The major organs affected are discussed in three categories: (1) kidney, (2) immune system, and (3) other organs. The second area of concentration is molecular toxicology, which will include a discussion of the chemistry of nickel, its binding to small and large molecular weight ligands, and, finally, its cellular effects. The third major area involves a discussion of the carcinogenicity and genotoxicity of nickel compounds. This section focuses on mechanisms, using studies conducted in vivo and in vitro. It also includes a discussion of the assessment of the carcinogenicity of nickel compounds.

Variable incidence of nickel dermatitis

The incidence of nickel sensitivity in Ljubljana, Yugoslavia, was stable in the periods 1972-1976 (6.7%) and 1977-1981 (6.3%). An increase became apparent when the incidence rose to 8.0% in 1982, and 9.1% in 1982-1986. The sex ratio in 1972-1976 was 2:1 with a female predominance, doubling to 4:1 in 1977-1981 and doubling again to 9:1 in 1982-1986. The highest incidence was in the age groups of 11-20 and 21-30 years. Nickel remains a rare cause of occupational dermatitis. Cheap metal jewelry is the likely source of the increased incidence.

Epidemiology of nickel allergy: results of a follow-up analysis of patients with positive patch tests to nickel

In a previous paper, we reported on nickel sensitivity in 2400 consecutive patients in 5 countries. 3 years later, we reassessed 104 of the 157 nickel-positive patients of this former study and found 13 now to be negative to nickel sulphate. Nearly all the others can no longer tolerate nickel contact. 68 patients were free from nickel dermatitis, 16 showed a very mild eczema or dyshidrosis, and 13 were suffering from chronic hand dermatitis. 42 of 104 patients had changed their occupation, 36 successfully, with clearance of skin lesions. Rehabilitation by avoidance of nickel-containing costume jewelry, wrist-watches and clothing buckles, and by change of occupation, is possible and necessary.

Allergic contact dermatitis of the face from contact with nickel and ammoniated mercury in spectacle frames and skin-lightening creams

A total of 507 (M 121, F 386) cases of facial dermatitis were investigated, of whom 308 (M 49, F 259) had eczema confined to the face. The prevalence of positive patch tests was 45% (229/507). Among all the patients, the 2 most frequent allergens were nickel (15.2%) and ammoniated mercury (6.1%), with the incidence of nickel sensitivity in men (20%) being greater than in women (13.7%). 56% of the nickel-positive cases were caused by metal spectacle frames. Taiwan's high number of spectacle-wearers, its subtropical climate and the characteristic oriental facial structure are possibly major contributing factors. Most ammoniated mercury (AM)-sensitive cases resulted from cosmetics. Skin-lightening creams are widely used in Taiwan, but their content is poorly controlled. According to consumer reports, 14.9% (48/322) had applied AM-containing cosmetics. Of all the cosmetics tested for mercury, 2.2% (60/2711) were positive.