Analysis of allergens in metalworking fluids

Increasing non-cosmetic exposure and sensitization to isothiazolinones require action for prevention: Review

Frequent use of methylchloroisothiazolinone/methylisothiazolinone (MCI/MI) and MI in cosmetic products has been the main cause of widespread sensitization and allergic contact dermatitis to these preservatives (biocides). Their use in non-cosmetic products is also an important source of sensitization. Less is known about sensitization rates and use of benzisothiazolinone (BIT), octylisothiazolinone (OIT), and dichlorooctylisothiazolinone (DCOIT), which have never been permitted in cosmetic products in Europe. BIT and OIT have occasionally been routinely patch-tested. These preservatives are often used together in chemical products and articles. In this study, we review the occurrence of contact allergy to MI, BIT, OIT, and DCOIT over time, based on concomitant patch testing in large studies, and case reports. We review EU legislations, and we discuss the role of industry, regulators, and dermatology in prevention of sensitization and protection of health. The frequency of contact allergy to MI, BIT, and OIT has increased. The frequency of contact allergy to DCOIT is not known because it has seldom been patch-tested. Label information on isothiazolinones in chemical products and articles, irrespective of concentration, is required for assessment of relevance, information to patients, and avoidance of exposure and allergic contact dermatitis.

Contact sensitization to benzisothiazolinone: IVDK-data of the years 2002 to 2021

BACKGROUND

Benzisothiazolinone (BIT; CAS no. 2634-33-5) is used as a biocide in various products, including water-based paints, metalworking fluids, and household products. In recent years, increasing sensitization rates have been observed in Europe.

OBJECTIVE

To describe a time trend of sensitization to BIT, analyse concomitant reactions, and identify patients with increased risk of BIT sensitization.

METHODS

Retrospective analysis of data from 26 739 patients patch tested with BIT, sodium salt, 0.1% petrolatum as part of several special test series within the Information Network of Departments of Dermatology (IVDK), 2002 to 2021.

RESULTS

Positive reactions to BIT were noted in 771 patients (2.9%). Sensitization frequency varied over time and increased in recent years, peaking at 6.5% in 2020. Painters and metalworkers handling metalworking fluids, but not cleaners, had a significantly increased risk of BIT sensitization. From our data, there is no evidence of immunological cross-reactivity between BIT and other isothiazolinones.

CONCLUSION

The increasing frequency of sensitization justifies adding BIT to the baseline series. More research on the clinical relevance of positive patch test reactions to BIT and the cause for the rising numbers of BIT sensitization is needed.

HIGHLIGHTS

Frequency of sensitization to BIT has increased in recent years. The increasing frequency of sensitization justifies adding BIT to the baseline series. Painters and metalworkers handling metalworking fluids, but not cleaners, has a significantly increased risk of BIT sensitization. We found no evidence of immunological cross-reactivity between BIT and other isothiazolinones.

Formaldehyde Release From Personal Care Products: Chromotropic Acid Method Analysis

BACKGROUND

Preservatives such as formaldehyde and formaldehyde releasers (F/FRs) are found in personal care products. Studies from Europe and Israel have indicated that products with undeclared F/FRs on product labels may have detectable levels of formaldehyde.

OBJECTIVE

The aim of the study was to determine the presence of formaldehyde in samples of US personal care products.

METHODS

Fifty-four baby and adult products were tested with the chromotropic acid method. A blinded investigator graded the color change as mild, moderate, or strong.

RESULTS

All 8 products declaring F/FRs resulted in a deep purple color change, indicating a strong reaction. Of the 46 products with undeclared F/FRs, 4 (8.6%) were found to release formaldehyde. All 4 resulted in a light purple color change, indicating a mild reaction.

CONCLUSIONS

Overall, 4 of 54 products (7.4%) had label information, which did not match chromotropic acid method testing results. Clinicians and formaldehyde-allergic individuals should be aware of the limitations of product ingredient labeling in managing allergic contact dermatitis to formaldehyde.

Safety Assessment of Tromethamine, Aminomethyl Propanediol, and Aminoethyl Propanediol as Used in Cosmetics

The Cosmetic Ingredient Review (CIR) Expert Panel (Panel) reviewed the safety of tromethamine, aminomethyl propanediol, and aminoethyl propanediolas used in cosmetics. All 3 ingredients are reported to function in cosmetics as pH adjusters, and tromethamine and aminomethyl propanediol are also reported to function as fragrance ingredients. The Panel reviewed relevant animal and human data related to these ingredients, along with a previous safety assessment of aminomethyl propanediol. The Panel concluded that tromethamine, aminomethyl propanediol, and aminoethyl propanediol are safe in cosmetics in the practices of use and concentration as given in this safety assessment.

Sensitization to, and allergic contact dermatitis caused by, colophonium in north-eastern Italy in 1996 to 2016 with a focus on occupational exposures

BACKGROUND

Colophonium is a natural substance derived from Pineaceae trees. It is used in a wide range of consumer and occupational products because of its tackiness, and is a known sensitizer.

OBJECTIVES

To analyse the temporal trend of contact allergy to colophonium in north-eastern Italy, and to evaluate the associations with occupations in our geographical area.

METHODOLOGY

From 1996 to 2016, 27 381 patients with suspected allergic contact dermatitis were patch tested in north-eastern Italy. Individual characteristics were documented by use of a standardized questionnaire in 6 departments of dermatology or occupational medicine.

RESULTS

The overall prevalence of colophonium sensitization was 1.67%; the prevalence was significantly higher in women (1.75%) than in men (1.49%). No significant differences among departments were observed. We found significant associations between colophonium sensitization and being a student (odds ratio [OR] 4.64; 95% confidence interval [CI]: 1.04-20.6), being a farmer or fishermen (OR 3.63; 95%CI: 1.21-10.84), being a housekeeper (OR 2.02; 95%CI: 1.08-3.77), and being retired (OR 2.06; 95%CI: 1.08-3.92).

CONCLUSION

Our study showed that contact allergy to colophonium is still relevant in north-eastern Italy. The frequency of sensitization has dropped significantly over a period of 10 years, but students and farmers/fishermen still have sensitization prevalences above 3.5%. Our results are in line with European data.

Phosphorus Depletion as a Green Alternative to Biocides for Controlling Biodegradation of Metalworking Fluids

Metalworking fluids (MWFs) are used as lubricants and coolants in the manufacturing operations. Their biodeterioration, while in operation, is a widespread problem leading to poor performance and worker health issues. Adding biocides, though effective in reducing microbial growth, leads to the production of more recalcitrant wastewaters that are difficult to dispose or recycle on-site. Increasing environmental concerns have led to robust legislation for reducing/eliminating the use of toxic biocides in MWFs, stimulating a growing interest in the development/application of alternative biological preservation strategies. In this study, inducing nutrient imbalance was investigated for controlling microbial growth in MWFs. Phosphorus was immobilized employing insoluble La₂O₃ to form LaPO₄. Concentrations of La₂O₃ greater than 0.08%w (%w = weight percent) completely inhibited microbial growth (from 1.4 × 10⁷ to 0 CFU/mL) and hindered biodegradation. Raman spectroscopy suggested that La₂O₃ converted intracellular phosphorus into LaPO₄. The growth inhibition potentials of both 0.06%w La(NO₃)₃ and La₂O₃ were found to be superior to formaldehyde. The antimicrobial property of La₂O₃ (i.e., inhibition) was tenable by adding sufficient phosphate, acting as an on/off switch for controlling microbial growth in MWFs. This technology offers the potential to reduce/eliminate the use of biocides in MWFs, improves the feasibility of end-of-life biological treatment, and closes the water loop.

Skincare products containing low concentrations of formaldehyde detected by the chromotropic acid method cannot be safely used in formaldehyde-allergic patients

BACKGROUND

Formaldehyde is a well-known contact sensitizer. Formaldehyde releasers are widely used preservatives in skincare products. It has been found that formaldehyde at concentrations allowed by the European Cosmetics Directive can cause allergic contact dermatitis. However, we still lack information on whether formaldehyde at low concentrations affects dermatitis in formaldehyde-allergic individuals.

OBJECTIVES

To study the effects of low concentrations of formaldehyde on irritant contact dermatitis in formaldehyde-allergic individuals.

METHODS

Fifteen formaldehyde-allergic individuals and a control group of 12 individuals without contact allergy to formaldehyde and formaldehyde releasers were included in the study. The individuals performed the repeated open application test (ROAT) during 4 weeks with four different moisturizers releasing formaldehyde in concentrations that had been determined as > 40, 20-40, 2·5-10 and 0 p.p.m. by the chromotropic acid (CA) spot test. Dimethyloldimethylhydantoin was used as a formaldehyde releaser in the moisturizers. The ROAT was performed on areas of experimentally induced sodium lauryl sulfate dermatitis. The study was double blind, controlled and randomized.

RESULTS

Nine of the 15 formaldehyde-allergic individuals had reappearance or worsening of dermatitis on the areas that were treated with moisturizers containing formaldehyde. No such reactions were observed in the control group (P < 0·001) or for the moisturizers without formaldehyde in the formaldehyde-allergic individuals (P < 0·001).

CONCLUSIONS

Our results demonstrate that the low concentrations of formaldehyde often found in skincare products by the CA method are sufficient to worsen an existing dermatitis in formaldehyde-allergic individuals.

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.

Formaldehyde-releasers: relationship to formaldehyde contact allergy. Metalworking fluids and remainder. Part 1

This is part of a series of review articles on formaldehyde-releasers and their relationship to formaldehyde contact allergy. Formaldehyde-releasers used in metalworking fluids (MWF) and a group of releasers not presented in previous articles are discussed. Here, in Part 1 of the article, there is a short overview of the composition and functions of MWF, the function of biocides in them, and adverse reactions to MWF. In addition, the releasers in MWF that have caused contact allergy are presented with CAS, synonyms, molecular formula, chemical structure, applications, patch test studies, and amount of formaldehyde released by them. In Part 2 of the article, the relationship between formaldehyde-releasers used in MWF and formaldehyde contact allergy is discussed as are data on miscellaneous releasers not previously presented, followed by a discussion of Parts 1 and 2 of the article.

Hand dermatitis: a focus on allergic contact dermatitis to biocides

Hand dermatitis is a common disease of the skin resulting in significantly decreased quality of life. Allergic contact dermatitis is a frequent cause of hand dermatitis. Recent studies have revealed that biocides used as preservatives are frequent allergens affecting the hands. This article reviews common biocides implicated in hand dermatitis.