Nine years of patch testing with isocyanates in a clinic of occupational dermatology

BACKGROUND

Isocyanates are used as starting materials of polyurethane (PU) products. They are relatively important occupational skin sensitizers.

OBJECTIVES

To analyse results of a large isocyanate patch test series of 19 isocyanate test substances and 4,4'-diaminodiphenylmethane (MDA), a marker of 4,4'-diphenylmethane diisocyanate (MDI) hypersensitivity.

METHODS

Test files were screened for positive reactions in the isocyanate series. Patients with positive reactions were analysed for occupation, exposure and diagnosis.

RESULTS

In 2010-2019, 53 patients had positive reactions in the series (16% of 338 patients tested). MDA, the well-established screening substance for MDI allergy, was positive in 30 patients, an in-house monomeric MDI test substance in 23 patients and 3 different polymeric MDI test substances in 19-21 patients. We diagnosed 16 cases of occupational allergic contact dermatitis (OACD) from MDI including 3 pipe reliners. Hexamethylene-1,6-diisocyanate (HDI) oligomers in paint hardeners caused 5 cases of OACD, more cases than 2,4-toluene diisocyanate (TDI; n = 3) and isophorone diisocyanate (IPDI; n = 1) put together.

CONCLUSIONS

In contrast to previous studies, polymeric MDI test substances were not superior to a monomeric MDI. Pipe reliners may get sensitised not only by epoxy products and acrylates but also by MDI in hardeners of PU pipe coatings. HDI oligomers were the second most important causes of OACD after MDI.

Assessing contact dermatitis risk among Manitoba workers in the Manitoba Occupational Disease Surveillance System

INTRODUCTION

This exploratory study aimed to assess contact dermatitis (CD) risk among workers using the Manitoba Occupational Disease Surveillance System (MODSS).

METHODS

The MODSS linked accepted time-loss claims from the Workers' Compensation Board of Manitoba (2006-2019), with administrative health data from medical and hospital records (1996-2020). CD risk by occupation and industry (hazard ratio, 95% confidence intervals) was estimated using Cox proportional hazard models, adjusted for age and stratified by sex.

RESULTS

Increased risk of new onset CD was observed among some occupations and industries with known skin irritants and allergens. Some occupations with known increased risks of CD remained elevated when removing the accepted WCB cases was performed, suggesting that all CD cases in these occupations may not show up in WCB statistics. Increased risk was also observed for occupations and industries with unknown exposures related to CD, whereas some groups known to be at risk of CD were not observed to have elevated risks in this cohort.

DISCUSSION

The MODSS successfully identified some occupations and industries known to be at high risk of occupational CD, but not others. Some occupations not typically associated with work-related CD were also identified, which warrants further investigation.

Occupational Hand Dermatitis

PURPOSE OF REVIEW

Occupational hand dermatitis is a common work-related disorder of the skin. Prevention and management of this disease is critical to improving workers' quality of life and for occupation-specific retention.

RECENT FINDINGS

This is a critical review of the current literature on occupational hand dermatitis. Occupational dermatitis continues to have a high prevalence among workers although the overall incidence may be slowly decreasing. Irritant contact dermatitis due to wet work exposure is the most common cause of occupational hand dermatitis. Healthcare workers, hairdressers, and metal workers are at particularly high risk for this disease. While some prevention programs have been ineffective in mitigating occupational hand dermatitis, other more resource-intensive initiatives may have benefit. Continued research is needed on ways to manage wet work exposures and on scalable, effective prevention programs for occupational hand dermatitis. The spectrum of culprit contact allergens continues to evolve, and vigilance for potential occupation-specific allergens remains important.

Characterization of patients with occupational allergy to two new epoxy hardener compounds

Background

The practical importance of two recently described epoxy hardener allergens—1,3‐benzenedimethanamine, N‐(2‐phenylethyl) derivatives (1,3‐BDMA‐D) and hydrogenated formaldehyde benzenamine polymer (FBAP)—as occupational allergens remains to be defined.

Objectives

To describe patients diagnosed at the Finnish Institute of Occupational Health (FIOH) with positive reactions to 1,3‐BDMA‐D or FBAP.

Methods

We searched FIOH's patch‐test files from January 2017 to December 2020 for patients examined due to suspected occupational contact allergy to epoxy compounds. We analyzed the patch‐test results and sources of exposure to various epoxy hardeners and focused on occupations, symptoms, and the sources of exposure to 1,3‐BDMA‐D and FBAP.

Results

During the study period, 102 patients were examined at FIOH for suspected occupational contact allergy to epoxy compounds. Of these, 19 (19%) were diagnosed with contact allergy to 1,3‐BDMA‐D (n = 10) or FBAP (n = 12). The largest occupational group was sewage pipe reliners (n = 8). Seven different hardener products contained FBAP, whereas 1,3‐BDMA‐D was present in only one hardener used by spray painters.

Conclusions

A substantial number of patients with suspected occupational epoxy resin system allergy tested positive to in‐house test substances of 1,3‐BDMA‐D and/or FBAP.

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.

Occupational Dermatitis and Urticaria

Occupational contact dermatitis is the most common occupational skin disease (OSD), and most of them are irritant in nature. There is less information available about contact urticaria than contact dermatitis. There are several strategies to prevent OSD, although workplace studies suggest there are gaps in their use in the workplace. Because early detection leads to improved outcomes, screening for dermatitis in industries such as health care would be useful. Both diagnosis and management involve 2 components: the actual disease diagnosis and medical treatment and the work-relatedness and management of the workplace to reduce exposures.

Patterns of positive patch test reactions to formaldehyde and formaldehyde releasers at the Finnish Institute of Occupational Health from 2007 to 2020

BACKGROUND

Formaldehyde is an important contact sensitizer. Formaldehyde releasing substances induce positive reactions in formaldehyde-allergic patients, but there are also reactions independent of formaldehyde allergy. In an earlier study, stronger formaldehyde reactions led to more positive reactions to quaternium-15.

OBJECTIVES

To analyze patterns of positive patch test reactions to formaldehyde and different formaldehyde releasers.

METHODS

Patch test files of 1497 patients investigated during the period November 2007-August 2020 were retrospectively reviewed for positive reactions to formaldehyde and its releasers. During the study period, almost all (≥99.3%) patients were tested with a formaldehyde dilution series and six formaldehyde releasers.

RESULTS

Ninety-three patients tested positive to formaldehyde; 80% of these had positive reactions to at least one formaldehyde releaser, most often benzylhemiformal. There were only nine independent contact allergies to formaldehyde releasers. There were only two reactions to 2-bromo-2-nitropropane-1,3-diol and they occurred in formaldehyde-negative patients. In patients with extreme (+++) reactions to formaldehyde, concomitant positive reactions to any of the other 11 investigated formaldehyde releasers were more common than in patients with milder formaldehyde reactions.

CONCLUSIONS

Strong formaldehyde reactions were associated with positive reactions to formaldehyde releasers.

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.

European Surveillance System on Contact Allergies (ESSCA): Characteristics of patients patch tested and diagnosed with irritant contact dermatitis

BACKGROUND

Irritant contact dermatitis (ICD) is caused by the acute locally toxic effect of a strong irritant, or the cumulative exposure to various weaker physical and/or chemical irritants.

OBJECTIVES

To describe the characteristics of patients with ICD in the population patch tested in the European Surveillance System on Contact Allergies (ESSCA; www.essca-dc.org) database.

METHODS

Data collected by the ESSCA in consecutively patch-tested patients from January 2009 to December 2018 were analyzed.

RESULTS

Of the 68 072 patients, 8702 were diagnosed with ICD (without concomitant allergic contact dermatitis [ACD]). Hand and face were the most reported anatomical sites, and 45.7% of the ICD was occupational ICD (OICD). The highest proportions of OICD were found in metal turners, bakers, pastry cooks, and confectionery makers. Among patients diagnosed with ICD, 45% were found sensitized with no relevance for the current disease.

CONCLUSIONS

The hands were mainly involved in OICD also in the subgroup of patients with contact dermatitis, in whom relevant contact sensitization had been ruled out, emphasizing the need for limiting irritant exposures. However, in difficult-to-treat contact dermatitis, unrecognized contact allergy, or unrecognized clinical relevance of identified allergies owing to incomplete or wrong product ingredient information must always be considered.

Allergic contact dermatitis to phenol-formaldehyde resin at a single tertiary dermatology centre

BACKGROUND

Phenol-formaldehyde resin 2 (PFR2) has been shown to be a useful marker of contact allergy (CA) to various phenol-formaldehyde resins. These compounds are used in several industries as solids, powders, or semisolid resins, and are known to be sensitizing agents.

OBJECTIVES

The aims were to investigate contact allergy to PFR2 in a single tertiary dermatology centre, to examine associated simultaneous allergic reactions, and to identify cases of allergic contact dermatitis (ACD) to PFR2.

METHODS

A retrospective study was performed of patients patch tested to PFR2 between 1 January 2003 and 17 June 2020.

RESULTS

In all, 337 of 7922 patients were tested to PFR2 and 16 (4.7%) reacted. Of those 16 individuals, six (37.5%) had a relevant reaction (1.8% of total). Simultaneous allergic reactions were noted to colophonium in eight (50.0%) patients, Myroxylon pereirae in five (31.3%), and fragrance mix I (FMI) of three cases (18.8%).

CONCLUSION

Contact allergy to PFR2, even in a selected population of patients, is uncommon. However, patients exposed to plastics and glues, or who work with wood products should be routinely patch tested to a plastics and glues series containing PFR2. We recommend that all centres include PFR2 in their plastics and glues series.

Allergic contact dermatitis and other occupational skin diseases in health care workers in the Finnish Register of Occupational Diseases in 2005-2016

BACKGROUND

Health care workers are an important risk group for occupational skin disease (OSD).

AIMS

To study diagnoses and causes of OSDs in health care workers in the Finnish Register of Occupational Diseases (FROD) in 2005-2016.

METHODS

We searched the FROD for dermatological cases (a) in health care-related occupations defined by ISCO-08 and (b) in the industrial branch of health care defined by European industry standard classification system (NACE rev. 2).

RESULTS

Health care workers comprised 19% of all OSD cases in the FROD, and irritant contact dermatitis dominated the diagnoses. Nurses and assistant nurses were the largest occupational groups with incidence rates of 3.3 and 2.7/10 000 person years, respectively. Rubber chemicals were by far the most common causative agents of allergic contact dermatitis (ACD) followed by preservatives, the latter mainly comprising isothiazolinones and formaldehyde. Acrylates were important allergens in dental professions. Metals and coconut fatty acid derivatives were the next largest causative groups for ACD. Drugs caused only 1% of the ACD cases.

CONCLUSIONS

Workers in different health care occupations do not have a uniform risk for OSD, but they share the risk for ACD due to rubber chemicals and various preservatives.

Hairdressers' occupational skin diseases in the Finnish Register of Occupational Diseases in a period of 14 years

BACKGROUND

Hairdressers have a high risk of occupational contact dermatitis caused by exposure to wet work and allergens in hairdressing chemicals.

OBJECTIVES

To examine the distribution of diagnoses of occupational skin diseases (OSDs) and their main causes in hairdressers based on a national register data on occupational diseases.

METHODS

We retrieved cases of recognized OSDs in hairdressers from the Finnish Register of Occupational Diseases (FROD) in years 2005-2018.

RESULTS

During the 14-year period, a total of 290 cases of recognized OSD in hairdressers were registered in the FROD. Allergic contact dermatitis (ACD) was diagnosed in 54%, irritant contact dermatitis in 44%, and contact urticaria (CU) in 5% of them. ACD was most commonly caused by hair dye products and their ingredients (N = 57), persulfates (N = 35), and preservatives (N = 35; mainly isothiazolinones). Acrylates emerged as hairdressers' occupational contact allergens (N = 8) probably due to introduction of structure nails into hair salons. Persulfates was the most common cause of CU.

CONCLUSIONS

ACD was the most common OSD in hairdressers. Our analysis confirms that preservatives are important causes of ACD in hairdressers in addition to hair dye products and persulfates. Acrylates emerged as hairdressers' occupational contact allergens, but contact allergy to perming agents remained rare.

Patch test results with the European baseline series and additions thereof in the ESSCA network, 2015-2018

BACKGROUND

Clinical surveillance of the prevalence of contact allergy in consecutively patch tested patients is a proven instrument to continually assess the importance of contact allergens (haptens) assembled in a baseline series.

OBJECTIVES

To present current results from the European Surveillance System on Contact Allergies, including 13 countries represented by 1 to 11 departments.

METHODS

Anonymized or pseudonymized patch test and clinical data from various data capture systems used locally or nationally as transferred to the Erlangen data centre were pooled and descriptively analysed after quality control.

RESULTS

In the 4 years (2015-2018), data from 51 914 patients patch tested with the European baseline series (EBS) of contact allergens were analysed. Contact allergy to nickel was most frequent (17.6% positive), followed by contact allergy to fragrance mix I (6.9%), methylisothiazolinone (MI; 6.2%), and Myroxylon pereirae resin (balsam of Peru; 5.8%).

CONCLUSIONS

While the prevalence of MI contact allergy decreased substantially following regulatory intervention, the persistently high levels of allergy to metals, fragrances, other preservatives, and rubber chemicals point to problems needing further research and, potentially, preventive efforts. Results with national additions to the baseline series provide important information on substances possibly to be considered for inclusion in the EBS.