Methylchloroisothiazolinone and methylisothiazolinone contact allergy: an occupational perspective

Electrochemical Characterization and Voltammetric Determination of Methylisothiazolinone on a Boron-Doped Diamond Electrode

The electrochemical properties of methylisothiazolinone (MIT), the most widely used preservative, were investigated by cyclic (CV) and differential pulse voltammetry (DPV) to develop a new method for its determination. To our knowledge, this is the first demonstration of a voltammetric procedure for the determination of MIT on a boron-doped diamond electrode (BDDE) in a citrate-phosphate buffer (C-PB) environment. The anodic oxidation process of methylisothiazolinone, which is the basis of this method, proved to be diffusion-controlled and proceeded with an irreversible two-electron exchange. The radical cations, as unstable primary products, were converted in subsequent chemical reactions to sulfoxides and sulfones, and finally to more stable final products. Performed determinations were based on the DPV technique. A linear calibration curve was obtained in the concentration range from 0.7 to 18.7 mg L^-1, with a correlation coefficient of 0.9999. The proposed procedure was accurate and precise, allowing the detection of MIT at a concentration level of 0.24 mg L^-1. It successfully demonstrated its suitability for the determination of methylisothiazolinone in household products without the need for any separation steps. The proposed method can serve as an alternative to the prevailing chromatographic determinations of MIT in real samples.

Occupational allergic contact dermatitis: A 24-year, retrospective cohort study from Turkey

BACKGROUND

Limited data exist on occupational allergic contact dermatitis (OACD) in Turkey.

OBJECTIVES

To investigate the epidemiologic profile of OACD in Turkey.

METHODS

A retrospective cohort study on 294 patients with OACD among 2801 consecutively patch-tested patients in the Allergy Unit of the Dermatology Department of İstanbul Faculty of Medicine between 1996 and 2019.

RESULTS

The overall prevalence of OACD was 10.5%, showing a male predominance. OACD was most frequently seen in construction workers (45.2%), followed by hairdressers, metalworkers, health care workers, and miscellaneous. The main relevant allergens were chromium in cement, thiurams in rubber gloves, hairdressing chemicals, resins/glues/plastics, metals, isothiazolinones, and fragrances. Hands were the mainly involved site (95.6%). Airborne eczema was observed in 21.4%. Hand and foot eczema and co-sensitizations to chrome and thiuram and chrome and cobalt were significantly associated with being a construction worker. Sensitizations to isothiazolinones in house painters, ammonium persulfate and p-phenylenediamine in hairdressers, and colophonium increased after 2010.

CONCLUSION

This was the largest group of data on OACD from Turkey, reflecting the importance of rubber glove allergy in all occupations and the striking increase in ammonium persulfate allergy among hairdressers. Chrome and cobalt were still the main cement allergens in Turkey, where the cement directive is not yet in force.

Amended Safety Assessment of Methylchloroisothiazolinone and Methylisothiazolinone as Used in Cosmetics

The Expert Panel for Cosmetic Ingredient Safety (Panel) reassessed the safety of the mixture Methylchloroisothiazolinone (MCI)/Methylisothiazolinone (MI), which functions as a preservative in cosmetic products. The Panel reviewed relevant animal and human data provided in this safety assessment, and data from the previously published safety assessment of this mixture, and concluded that MCI/MI is safe in cosmetics when formulated to be nonsensitizing, based on the results of a quantitative risk assessment or similar methodology; however, at no point should concentrations exceed 7.5 ppm in leave-on products or 15 ppm in rinse-off products.

Occupational Contact Dermatitis: An Update

Occupation contact dermatitis (CD) is a common inflammatory skin condition impacting every professional industry in the United States. It is associated with significant personal and professional distress, loss of revenue, and decreased productivity. Occupational CD is further subdivided into irritant CD and allergic CD. Frequently, workers may suffer from a combination of both types. Numerous workplace exposures are implicated, but there are several themes across professions, such as CD related to frequent handwashing and wet work. A detailed occupational history, physical examination, and patch testing can help to make the diagnosis. Treatment includes identification of the substance and avoidance, which often is quite challenging.

Occupational contact dermatitis: Retrospective analysis of North American Contact Dermatitis Group Data, 2001 to 2016

BACKGROUND

Patch testing is an important diagnostic tool for suspected allergic contact dermatitis (ACD) in occupational settings.

OBJECTIVE

Provide an overview of occupational skin disease (OSD) and an analysis of occupational ACD in North American patients undergoing patch testing between 2001and 2016.

METHODS

Patients with OSD were analyzed for frequency of allergic reactions to a screening series of allergens, occupational relevance, location of skin disease, and exposure sources. Demographic, occupation, and industry information were recorded.

RESULTS

Of 38,614 patients evaluated, 4471 (11.6%) had OSD, of whom 3150 (70.5%) had ACD. The most common occupationally related allergens included rubber accelerators, preservatives, and bisphenol A epoxy resin. Hands (75.8%), arms (30.0%), and face (15.9%) were common sites of dermatitis. The occupations most affected were service workers and machine operators.

LIMITATIONS

Our cohort may not reflect the general working population.

CONCLUSION

This study identified common occupational allergens, exposure sources, and occupations/industries at risk. This information may help the clinician evaluate and manage patients with occupational contact dermatitis.

Methylchloroisothiazolinone/methylisothiazolinone and methylisothiazolinone contact allergy: A 24-year, single-center, retrospective cohort study from Turkey

BACKGROUND

Methylchloroisothiazolinone/methylisothiazolinone (MCI/MI) and MI allergy caused a global epidemic during the period 2010 to 2015, reaching its peak in 2013/14.

OBJECTIVE

To investigate the characteristics of MCI/MI and MI allergy in Turkey over 24 years.

METHODS

A total of 2310 patients patch tested between 1996 and 2019 with MCI/MI 0.01% aq. or MCI/MI 0.02% aq., with or without MI 0.2% aq., were analyzed.

RESULTS

The overall prevalence of contact sensitization was 3.3% (n = 77) with a peak level of 16.4% in 2015. The prevalence gradually decreased thereafter, but was still high (6.5%) in 2019. Seventy-three patients had clinically relevant sensitizations. MI could detect clinically relevant sensitizations in all seven patients with a negative patch test reaction to MCI/MI 0.02%. Non-occupational allergic contact dermatitis (ACD) was most frequently seen, mainly in women, with hand/face eczema from rinse-off or leave-on cosmetics, such as wet wipes. Occupational ACD was mainly seen among men with airborne eczema from wall paints in house painters, or with hand eczema from hair gel/wax in men's barbers.

CONCLUSIONS

The prevalence of MCI/MI and MI sensitization in Turkey following the peak in 2015 is still high. This is probably due to the currently allowed level of 100 ppm for MI in rinse-off cosmetics. This needs to be urgently reduced.

Isothiazolinone Biocides: Chemistry, Biological, and Toxicity Profiles

The importance of isothiazole and of compounds containing the isothiazole nucleus has been growing over the last few years. Isothiazolinones are used in cosmetic and as chemical additives for occupational and industrial usage due to their bacteriostatic and fungiostatic activity. Despite their effectiveness as biocides, isothiazolinones are strong sensitizers, producing skin irritations and allergies and may pose ecotoxicological hazards. Therefore, their use is restricted by EU legislation. Considering the relevance and importance of isothiazolinone biocides, the present review describes the state-of-the-art knowledge regarding their synthesis, antibacterial components, toxicity (including structure–activity–toxicity relationships) outlines, and (photo)chemical stability. Due to the increasing prevalence and impact of isothiazolinones in consumer’s health, analytical methods for the identification and determination of this type of biocides were also discussed.

Occupational Dermatosis

PURPOSE OF REVIEW

The purpose of this review is to provide an update on occupational contact dermatitis including gaps in knowledge and practice. Occupational contact dermatitis is the most common occupational skin disease.

RECENT FINDINGS

New sources of exposure for known allergens and new allergens are continually being reported. Through clinical databases and surveillance systems, effects of prevention efforts or introduction of new allergens or new uses of known allergens can be monitored. Though the diagnostic process is clear, there are delays in workers seeking care. As early detection and intervention improves outcomes, screening should be implemented. Gaps in primary prevention in the workplace are identified and should be addressed to reduce the burden of disease. Surveillance systems support the prevention mandate. Understanding limitations of our knowledge and identifying gaps in practice can lead to initiatives to address research and practice needs and improve prevention of occupational dermatoses.

Isothiazolinone in Residential Interior Wall Paint: A High-Performance Liquid Chromatographic-Mass Spectrometry Analysis

BACKGROUND

There is limited information regarding isothiazolinone content in residential wall paints in the United States.

OBJECTIVE

The aim of this study was to evaluate the prevalence of 5 isothiazolinones-methylisothiazolinone (MI), methylchloroisothiazolinone, benzisothiazolinone (BIT), butyl BIT, and octylisothiazolinone-in US residential wall paints.

METHODS

Forty-seven paints were obtained from retailers in Minneapolis/St Paul, Minnesota. Paint samples were assessed for the presence of the 5 isothiazolinones using high-performance liquid chromatographic-mass spectrometry.

RESULTS

At least 1 isothiazolinone was detected in all 47 paints. However, no paint contained butyl BIT, and only 1 paint had octylisothiazolinone. The MI and BIT were found in 96% and 94% of the paints, respectively. Methylisothiazolinone ranged in concentration from 17 to 358 ppm, whereas BIT varied from 29 to 1111 ppm. Methylchloroisothiazolinone was found solely in oil-based paints. Isothiazolinones were declared in 15% of Safety Data Sheets but did not correlate with high-performance liquid chromatographic-mass spectrometry. One "preservative-free" paint had BIT at 71.5 ppm. Paint sheen was not statistically associated with BIT or MI concentrations. Unpigmented paints and paints with volatile organic compound claims had significantly lower concentrations of MI, but not BIT.

CONCLUSIONS

All paints contained at least 1 isothiazolinone. Methylisothiazolinone and BIT were the most common. Safety Data Sheets are insufficient for ascertaining isothiazolinone content in US paints.

The Role of Cleaning Products in Epidemic Allergic Contact Dermatitis to Methylchloroisothiazolinone/Methylisothiazolinone

BACKGROUND

Sensitivity to methylchloroisothiazolinone (MCI)/methylisothiazolinone (MI) has increased rapidly over recent years. This increase is mainly related to the extensive use of high concentrations of MI in cosmetic products, although a growing number of cases of occupational allergic contact dermatitis are caused by MCI/MI.

OBJECTIVE

The aim of this study was to examine the association between the increase in MCI/MI sensitization and the work performed by the patients in our area.

METHODS

A retrospective study was undertaken of the records of a total of 1179 patients who had undergone contact skin patch tests for MCI/MI from January 2005 to December 2015. A multivariate logistic regression analysis was performed to identify the factors independently associated with sensitivity to MCI/MI.

RESULTS

A constant increase in MCI/MI sensitization was observed over the observation period. The only work associated with a significant increase in the prevalence of MCI/MI sensitization was cleaning, with 38.5% of the cleaning professionals with MCI/MI sensitization consulting for cosmetics-related dermatitis.

CONCLUSIONS

Occupational sensitization to MCI/MI in cleaning professionals is worryingly increasing. This, in turn, could possibly account for many cases of cosmetics-associated contact dermatitis. Our findings suggest that a review of the regulations with regard to isothiazolinone concentrations in industrial and household detergents is necessary.

The Health and Occupation Research Network: An Evolving Surveillance System

Vital to the prevention of work-related ill-health (WRIH) is the availability of good quality data regarding WRIH burden and risks. Physician-based surveillance systems such as The Health and Occupation Research (THOR) network in the UK are often established in response to limitations of statutory, compensation-based systems for addressing certain epidemiological aspects of disease surveillance. However, to fulfil their purpose, THOR and others need to have methodologic rigor in capturing and ascertaining cases. This article describes how data collected by THOR and analogous systems can inform WRIH incidence, trends, and other determinants. An overview of the different strands of THOR research is provided, including methodologic advancements facilitated by increased data quantity/quality over time and the value of the research outputs for informing Government and other policy makers. In doing so, the utility of data collected by systems such as THOR to address a wide range of research questions, both in relation to WRIH and to wider issues of public and social health, is demonstrated.