Fluctuations in the prevalence of chromate allergy in Denmark and exposure to chrome-tanned leather

Background. A recent Danish study showed a significant increase in the prevalence of chromate contact allergy after the mid‐1990s, probably as a result of exposure to leather products. Objectives. To reproduce the results by analysing data from the period 1992–2009 at Odense University Hospital, Denmark. The temporal development in the occurrence of chromate contact allergy and assumed causative exposures were investigated. Patients, Materials and Methods. A retrospective analysis of patch test data was performed (n = 8483), and medical charts from patients with chromate allergy (n = 231) were reviewed. Comparisons were made using the χ²‐test. A test of the reproducibility of the TRUE Test^® was also performed. Logistic regression analyses were used to test for associations. Results. No significant changes in the prevalence or exposure sources of chromate allergy during 1992–2009 were identified. Leather shoes (24.4%) were the most frequent exposure sources in chromate allergy, and were mainly registered in women, although the difference between men and women was not significant (P = 0.07). Cement and leather glove exposure occurred significantly more often in men than in women (P = 0.002). Foot dermatitis (40.3%) was the most frequent anatomical location, apart from hand eczema (60.6%). The reproducibility of the TRUE Test^® was 93.3%. Conclusions. Apart from hand eczema, the most frequent clinical picture of chromate allergy was foot dermatitis caused by leather shoe exposure. A tendency for an increasing prevalence of chromate contact allergy from 1997 was shown, but no significant change was detectable.     

Temporal trends of preservative allergy in Denmark (1985–2008)

Background: Most cosmetics and industrial products contain preservatives. Preservative allergy is common and, historically, changing contact allergy epidemics caused by preservatives have been observed. In 1997, Alan Dillarstone predicted a stable development of preservative allergy following mandatory ingredient labelling on cosmetic products. Objectives: To investigate the development in the prevalence of preservative allergy in Denmark over a 24‐year period (1985–2008) and to challenge the prediction made by Dillarstone. Patients/Methods: A retrospective analysis of patch test data was performed (n = 18179). Comparisons were made using a χ² test. Logistic regression analyses were used to test for associations. Results: The development of preservative allergy mirrored those of other European patch test centres. The development was not dependent on sex or age group. The prevalence was higher among women and those aged 41–60 years. Formaldehyde allergy was persistently prevalent over the study years. The overall prevalence of preservative allergy increased significantly (P_trend = 0.001), mainly because of patch testing with additional preservatives in recent years. Conclusions: Dillarstone's prediction was confirmed as the prevalence of contact allergy to individual preservatives remained relatively stable. However, the overall burden of preservative allergy seemed to increase. Introduction of new preservatives may add to the burden of contact allergy.     

Chromium in leather footwear - risk assessment of chromium allergy and dermatitis

Background. Chromium‐tanned leather footwear, which releases >3 ppm hexavalent Cr(VI), may pose a risk of sensitizing and eliciting allergic dermatitis. Objectives. To determine the content and potential release of chromium in leather footwear and to discuss the prevention of chromium contact allergy and dermatitis. Methods. Sixty pairs of leather shoes, sandals and boots (20 children's, 20 men's, and 20 women's) were purchased in Copenhagen and examined with X‐ray fluorescence spectroscopy. Chromium was extracted according to the International Standard, ISO 17075. The detection level for Cr(VI) was 3 ppm. Results. Chromium was identified in 95% of leather footwear products, the median content being 1.7% (range 0–3.3%). No association with store category or footwear category was found. A tendency for there to be a higher chromium content in footwear with high prices was shown (p_trend = 0.001). Cr(VI) was extracted from 44% of 18 footwear products, and, in three items, more than 10 ppm was extracted. One shoe had 62 ppm Cr(VI) extracted. Sandals seemed to be over‐represented among footwear with detectable Cr(VI). Cr(III) extraction reached a median value of 152 ppm. Conclusions. Most leather footwear contained chromium. Cr(VI) was extracted from a high proportion of leather footwear; this poses a risk of sensitization.     

Fluctuations in the prevalence of nickel and cobalt allergy in eczema patients patch tested after implementation of the nickel regulation in Denmark

Background. A recent Danish study showed that the prevalence of nickel allergy decreased among young female patients and increased among older female patients with dermatitis patch tested between 1985 and 2007 at Gentofte Hospital, Denmark. The prevalence of cobalt allergy remained unchanged. Objectives. To examine fluctuations in the prevalence of nickel and cobalt allergy after implementation of the nickel regulation, by analysing patch test results from male and female patients with dermatitis tested between 1992 and 2009 at Odense University Hospital, Denmark. Methods. A retrospective analysis of patch test data was performed (female, n = 5821; male, n = 3317). Comparisons were made using the chi‐square test for trend. Logistic regression analyses were used to test for associations. Results. The prevalence of nickel allergy decreased significantly among the 2–30‐year‐old female patients, from 29.8% in 1992–1997 to 19.6% in 2004–2009 (p < 0.001), whereas it increased significantly, from 6.9% in 1992–1997 to 11.1% in 2004–2009 (p = 0.04), among the >60‐year‐old female patients. The overall prevalence of cobalt allergy increased significantly, from 3.7% in 1992–1997 to 5.1% in 2004–2009 (p = 0.03). The overall prevalence of nickel and cobalt allergy among male patients during the test period was 5.2% and 2.2%, respectively, and no significant change across the test years was detected. Conclusions. The prevalence of nickel allergy decreased among young female patients and increased among older female patients with dermatitis, probably because of a cohort effect. The overall prevalence of cobalt allergy increased from 1992 to 2009. No significant trend in the prevalence of nickel and cobalt allergy among male patients was found.     

10-year prevalence of contact allergy in the general population in Denmark estimated through the CE-DUR method

The prevalence of contact allergy in the general population has traditionally been investigated through population-based epidemiological studies. A different approach is the combination of clinical epidemiological (CE) data and the World Health Organization-defined drug utilization research (DUR) method. The CE-DUR method was applied in Denmark to estimate the prevalence of contact allergy in the general population and compare it with the prevalence estimates from the Glostrup allergy studies. Contact allergy prevalence estimates ranging from very liberal ('worst case') to conservative ('best case') assumptions were based on patch test reading data in combination with an estimate of the number of persons eligible for patch testing each year based on sales data of the 'standard series'. The estimated 10-year prevalence of contact allergy ranged between 7.3% and 12.9% for adult Danes older than 18 years. The 10-year prevalence of contact allergy measured by CE-DUR was slightly lower than previous prevalence estimates from the Glostrup allergy studies. This could probably be explained by a decrease in nickel allergy. The CE-DUR approach holds the potential of being an efficient and easy monitoring method of contact allergy prevalence.     

Quantitative aspects of contact allergy to chromium and exposure to chrome-tanned leather

The potential of trivalent and hexavalent chromium to induce and elicit allergic contact dermatitis and the degree of chromium exposure from leather products are reviewed. Chromium dermatitis is often due to exposure in the occupational environment, with cement being one of the most common chromium sources. However, consumer products such as chromium(III)-tanned leather products are also an important source of chromium exposure. Apart from Cr(III), which is used for tanning, leather often also contains trace amounts of Cr(VI), which is formed by oxidation of Cr(III) during the tanning process. In a recent study of the Cr(VI) content of leather products bought on the Danish market, 35% of such articles had a Cr(VI) content above the detection limit of 3 p.p.m., ranging from 3.6 p.p.m. to 14.7 p.p.m. Leachable Cr(III) was detected at levels of 430-980 p.p.m. An examination of available dose-response studies showed that exposure to occluded patch test concentrations of 7-45 p.p.m. Cr(VI) elicits a reaction in 10% of the chromium-sensitive patients. When reviewing repeated open exposure studies, it is seen that either exposure to 5 p.p.m. Cr(VI) in the presence of 1% sodium lauryl sulfate (SLS) or exposure to 10 p.p.m. Cr(VI) alone both elicit eczema in chromium-sensitive patients. The eliciting capacity of Cr(III) has not been systematically investigated but, compared to Cr(VI), much higher concentrations are needed to elicit eczema.     

Patch test results with standard allergens over a decade

The results of 10 years of patch testing with standard allergens are reported. An increase of sensitivity was found in nickel. Sensitivity to chromate had decreased. Sex and age differences in the incidence of allergy to metals were analysed. Nickel allergy appeared to be more common among women and was of most importance in the younger age groups.     

Trend of contact allergy to cosmetic ingredients in Thais over a period of 10 years

Background. Contact allergy to cosmetic ingredients is common. However, there are no recent comprehensive studies on contact allergy to cosmetic ingredients in Asia. Objectives. To identify positive patch test reactions in patients tested at Siriraj Hospital, Bangkok, Thailand to allergens present in cosmetics. Methods. A retrospective review of medical records from the outpatient contact dermatitis clinic was conducted from January 1999 to December 2008. Patients with at least one positive patch test reaction to allergens associated with cosmetic ingredients were studied. The results were evaluated using Pearson's χ²‐test with Yates' continuity correction or Fisher's exact test where appropriate,and a p‐value <0.002 was considered to be statistically significant by Bonferroni correction. Results. There were 1247 cases (239 males and 1008 females; mean age 38.5 years). Fragrance chemicals and preservatives were the most commonly recognized cosmetic allergens. Ammoniated mercury was the only allergen that showed a significantly increased frequency over the 10‐year period (p = 0.0008). Conclusions. Our study showed that ammoniated mercury is an emerging cosmetic allergen, showing an increased prevalence in recent years in Thailand. A focus is required on emerging cosmetic allergens and what may account for the upward trend of cosmetic contact dermatitis.     

The frequency of fragrance allergy in a patch-test population over a 17-year period

Fragrances are widely encountered in our daily environment and are known to be a common cause of allergic contact dermatitis. We have reviewed our patch test data from 1980 to 1996 to establish whether the pattern of fragrance allergy has changed with time. During this period, 25,545 patients (10,450 male, 15,005 female) were patch tested with the European standard series. The mean annual frequency of positive reactions to the fragrance mix was 8.5% in females (range 6.1-10.9) and 6.7% in males (range 5.1-12.9). Females were 1.3 times more likely to be allergic to fragrance (P < 0.001, 95% confidence interval, CI 1.17-1.41). Males with fragrance allergy were older than females by 5.6 years (mean age 48.2 vs. 42.6 years; P < 0.001, 95% CI 3.9-7.3). The incidence of a concomitant positive patch test to balsam of Peru in fragrance-sensitive patients showed wide variation, suggesting that it is not a reliable marker of fragrance allergy. There was a positive correlation between the isomers isoeugenol and eugenol. Oak moss remained the most common overall allergen throughout the study, positive in 38.3% of females and 35.6% of males who were tested to the constituents of the fragrance mix. During the period of the study the incidence of positive tests to oak moss increased by 5% yearly (P = 0.001, 95% CI 2.2-8.7). The frequency of allergic reactions to eugenol and geraniol remained relatively constant. Isoeugenol and alpha-amyl cinnamic aldehyde sensitivity increased and hydroxycitronellal showed a slow decline. There was a striking reduction in the frequency of sensitivity to cinnamic aldehyde (by 18% yearly; P < 0.001, 95% CI 14.3-21.0) and cinnamic alcohol (by 9% yearly; P < 0.001, 95% CI 5.2-12.9); these are now uncommon fragrance allergens. These data show temporal trends which may reflect the frequency of population exposure to individual fragrances.     

Addition of ferrous sulfate to cement and risk of chromium dermatitis among construction workers

Lowering the water-soluble chromium content of cement to < 2 ppm has been suggested to diminish tile risk of allergic hand dermatitis caused by chromium among construction workers. The prevalence of chromium dermatitis was determined for a representative sample of 913 house construction workers and 707 concrete element prefabrications workers, with a questionnaire and clinical examination, before the use of cement with such H low content of water-soluble chromium was Lined on Finnish construction sites in 1987. The prevalence of allergic contact dermatitis caused by water-soluble chromium, diagnoses confirmed with patch tests among the workers with hand dermatitis, was 9/ 117 (7.7%). 4 of them were new 4/105 (4%) and 5 had been diagnosed earlier. In 1997, the prevalence of work-related hand dermatitis (allergic and irritant together) was 6.8% among the construction workers and 8.9% among the concrete element prefabrication workers. The Finnish Register of Occupational Diseases was checked for reports of chromium dermatitis and other forms of hand dermatitis from 1978 to 1992. The results indicated that, after 1987, the occurrence of allergic contact dermatitis caused by chromium decreased to less than 1/3 the previous level, whereas the occurrence of irritant contact dermatitis remained stable throughout the observation period. Regardless of some potential confounders, the addition of ferrous sulfate to cement during the production process may have reduced the number of cases of allergic contact dermatitis among construction and concrete element prefabrication workers. Our results agree with the results of Danish studies and Swedish observations.     

Frequency of contact allergy in German children and adolescents patch tested between 1995 and 2002: results from the Information Network of Departments of Dermatology and the German Contact Dermatitis Research Group

Allergic contact dermatitis (ACD) affects approximately 7% of the general population. To evaluate the frequency of ACD in children, we analysed patch test results collected by the Information Network of Departments of Dermatology between 1995 and 2002. Data of 285 children (6-12 year) and 2175 adolescent patients (13-18 year) were analysed to determine the frequency of sensitization to the 30 most common contact allergens, adjusting for age and sex. As control group, we defined adult patients (60-66 year, n = 7904). The top allergens in children were thimerosal, gentamicin sulphate, nickel-II-sulphate, ammoniated mercury, cobalt-II-chloride, fragrance mix, bufexamac, Compositae mix, propylene glycol and turpentine. The overall proportion of sensitized patients according to the patch test results was 52.6% in the children group compared to 49.7% in the adolescent group. These findings were similar in the adult group at 52.2%. The detailed analysis regarding sex, occupation, atopy, site of eczema and age showed distinct patterns in each group indicating age-specific exposures. Atopy-related diseases were more common in children compared to adults. On the basis of the data of this study, the relationship between atopy and the risk of development of ACD, at least in children, needs further investigation.     

Nickel,chromium and cobalt sensitization in a patch test population in north‐eastern Italy (1996–2010)

Background. Sensitization to nickel, cobalt and chromium is frequent in patch test populations. The prevalence is affected by geographical and socio‐cultural factors. Objectives. To investigate the temporal trend of nickel, cobalt and chromium contact sensitization between 1996 and 2010 in north‐eastern Italy. Patients/methods. Nineteen thousand and eighty‐eight patients (67.2% women and 32.8% men) with suspected allergic dermatitis underwent patch testing with the European baseline series. The associations between nickel, cobalt and chromium sensitization and patient age (in quintiles) and year of patch testing were investigated by means of multivariate logistic regression analysis. Results. The prevalence of nickel sensitization decreased significantly among younger women (≤26 years), from 38.3% (1996–1998) to 31.9% (2002–2004), 28.3% (2005–2007) and 29.0% (2008–2010), whereas an increase was observed in the 36–45‐year and 46–58‐year age groups. The overall prevalence of chromium sensitization dropped from 10.2% (1996–1998) to 4.6% (2008–2010) among women, and from 11.3% (1996–1998) to 5.9% (2008–2010) among men. The prevalence of cobalt sensitization increased among younger men (≤26 years), from 2.7% (1996–1998) to 7.3% (1999–2001), 9.6% (2002–2004), and 6.6% (2005–2007). Conclusions. Our study showed a decreasing trend of nickel sensitization (only among younger women) and of chromium sensitization in both sexes.