Prognosis of contact dermatitis in epoxy resin workers

In vitro methods for hazard assessment of industrial chemicals - opportunities and challenges

Allergic contact dermatitis (ACD) is a delayed-type hypersensitivity immune reaction mediated by T-lymphocytes as a result of repeated exposure of an allergen primarily on skin. ACD accounts for up to 95% of occupational skin diseases, with epoxy resins implicated as one of the most common causes of ACD. Efficient high-throughput in vitro screening for accurate identification of compounds and materials that may pose hazardous risks in the workplace is crucial. At present, the murine local lymph node assay is the 'method of choice' for predicting the sensitizing potency of contact allergens. As the 3Rs principles of reduction, refinement, and replacement in animal testing has gained political and economic momentum, several in vitro screening methods have been developed for identifying potential contact allergens. To date, these latter methods have been utilized primarily to assess the skin sensitizing potential of the chemical components of cosmetic products with scant research attention as to the applicability of these methods to industrial chemicals, particularly epoxy resins. Herein we review the currently utilized in vitro methods and identify the knowledge gaps with regard to assessing the generalizability of in vitro screening methods for assessing the skin sensitizing potential of industrial chemicals.

Occupational skin allergies: testing and treatment (the case of occupational allergic contact dermatitis)

Occupational contact dermatitis, including occupational allergic contact dermatitis, is one of the most common occupational diseases. Making a timely and accurate diagnosis is important to improving the outcome. Taking a work history and patch testing are essential elements in the diagnostic process. Management, based on an accurate diagnosis, must include both medical treatment to address the disease and workplace modifications as appropriate to reduce exposure the causative agents.

Occupational and non-occupational allergic contact dermatitis: a follow-up study

BACKGROUND/AIMS

The aim of this study was to obtain insight into the clinical course and prognosis of allergic contact dermatitis (ACD), including potential effects of genetic and environmental factors.

METHODS

Eighty-two patients with previously defined ACD acquired occupationally (OACD) or non-occupationally (NOACD) were patch retested and evaluated for the presence of persistent eczema, atopy and filaggrin mutations.

RESULTS

The crude risk for the persistence of a positive patch test (PT) reaction was 6.3 times higher (95% CI 3.63-11.0) for PT reactions assessed as '+++' compared to '++' reactions at the first PT. Among the categories of OACD, NOACD, age, gender, atopy, and the number of positive PT reactions at the first and second PT, only OACD (OR 10.0, 95% CI 1.95-51.2) and number of positive PT reactions at retesting (OR 3.85, 95% CI 1.57-9.44) were found to be predictors of persistent eczema.

CONCLUSIONS

Occupationally acquired contact allergy was emphasized as the most important factor in predicting poor prognosis of ACD.

U.K. standards of care for occupational contact dermatitis and occupational contact urticaria

The diagnosis of occupational contact dermatitis (OCD) and occupational contact urticaria (OCU) is a process that involves fastidious clinical and occupational history taking, clinical examination, patch testing and skin-prick testing. A temporal relationship of work and/or the presence of a rash on the hands only raises suspicion of an occupational cause, and does not necessarily confirm an occupational causation. The identification of allergy by patch or prick tests is a major objective, as exclusion of an offending allergen from the environment can contribute to clinical recovery in the individual worker and avoidance of new cases of disease. This can be a complex process where allergens and irritants, and therefore allergic and irritant contact dermatitis, may coexist. This article provides guidance to healthcare professionals dealing with workers exposed to agents that potentially cause OCD and OCU. Specifically it aims to summarize the 2010 British Occupational Health Research Foundation (BOHRF) systematic review, and also to help practitioners translate the BOHRF guideline into clinical practice. As such, it aims to be of value to physicians and nurses based in primary and secondary care, as well as occupational health and public health clinicians. It is hoped that it will also be of value to employers, interested workers and those with responsibility for workplace standards, such as health and safety representatives. Note that it is not intended, nor should it be taken to imply, that these standards of care override existing statutory and legal obligations. Duties under the U.K. Health and Safety at Work Act 1974, the Management of Health and Safety at Work Regulations 1999, the Control of Substances Hazardous to Health Regulations 2002, the Equality Act 2010 and other relevant legislation and guidance must be given due consideration, as should laws relevant to other countries.

Skin exposure to epoxy in the pipe relining trade - an observational study

BACKGROUND

Epoxy resin systems (ERSs) are frequent causes of occupational allergic contact dermatitis. Epoxy pipe relining has become a widely used alternative to replacing old and worn drain pipes in housing, and involves a high risk of skin exposure to ERSs.

OBJECTIVES

To map out work methods, protective measures and skin and surface contamination among workers involved in epoxy pipe relining, as a basis for prevention of occupational skin disease.

METHODS

Twenty-one employees in eight relining companies in Stockholm County were observed. Contact and contamination with ERSs and the use of personal protective equipment during relining work were noted.

RESULTS

Contamination by uncured ERSs on gloves, personal and shared tools and work areas was identified during mixing, wetting, installation, and cleaning. The gloves used were often inadequate for handling ERSs.

CONCLUSIONS

Relining pipes poses an extensive risk of uncured ERS exposure, and contamination was identified during the whole work process. Shared and personal tools and work areas were extensively contaminated. Changes in work routines and logistics for handling ERSs are essential, and knowledge among both employers and employees regarding the risks caused by ERS exposure is vital to create a safe work environment and prevent contact allergies.

Contact allergy to epoxy resin: risk occupations and consequences

BACKGROUND

Epoxy resin monomers are strong skin sensitizers that are widely used in industrial sectors. In Denmark, the law stipulates that workers must undergo a course on safe handling of epoxy resins prior to occupational exposure, but the effectiveness of this initiative is largely unknown.

OBJECTIVES

To evaluate the prevalence of contact allergy to epoxy resin monomer (diglycidyl ether of bisphenol A; MW 340) among patients with suspected contact dermatitis and relate this to occupation and work-related consequences.

PATIENTS/METHODS

The dataset comprised 20 808 consecutive dermatitis patients patch tested during 2005-2009. All patients with an epoxy resin-positive patch test were sent a questionnaire.

RESULTS

A positive patch test reaction to epoxy resin was found in 275 patients (1.3%), with a higher proportion in men (1.9%) than in women (1.0%). The prevalence of sensitization to epoxy resin remained stable over the study period. Of the patients with an epoxy resin-positive patch test, 71% returned a questionnaire; 95 patients had worked with epoxy resin in the occupational setting, and, of these, one-third did not use protective gloves and only 50.5% (48) had participated in an educational programme.

CONCLUSION

The 1% prevalence of epoxy resin contact allergy is equivalent to reports from other countries. The high occurrence of epoxy resin exposure at work, and the limited use of protective measures, indicate that reinforcement of the law is required.

Epoxy pipe relining - an emerging contact allergy risk for workers

BACKGROUND

Epoxy pipe relining is a method of repairing old and worn water pipes supplying households. The method, using epoxy resin systems (ERSs), involves creating a new pipe inside an existing pipe. Large amounts of epoxy are normally handled at small, temporary worksites.

OBJECTIVES

To describe working conditions and contact allergies to ERSs in 8 patients with occupational contact dermatitis related to their work in the relining trade.

METHODS

Eight patients with suspected work-related eczema in the relining trade were referred to our Occupational and Environmental Dermatology outpatient unit. They were examined and patch-tested between August 2010 and May 2011.

RESULTS

Seven patients were patch test-positive to ERSs, and 6 of 8 reacted to the epoxy resin (MW 340) in the baseline series. Five of the patients were patch test-positive to their own work products. Seven of the cases had to leave the relining trade because of skin problems.

CONCLUSIONS

Relining is a widely used alternative to replacing old pipes, and entails a risk of massive skin exposure to ERSs and consequently a high risk of developing allergic contact dermatitis. Further mapping of working methods and use of personal protective equipment (PPE) is crucial to reduce hazardous skin exposure.

A review of the impact of occupational contact dermatitis on quality of life

Occupational contact dermatitis (OCD) is the most common occupational skin disease in many countries. We reviewed the current evidence on how OCD impacts on quality of life (QoL). The three commonly used QoL questionnaires in OCD were the Short-Form Health Survey (SF-36), the Dermatology Life Quality Index (DLQI), and the Skindex. Despite the availability of a variety of validated QoL instruments, none of them is specific to OCD or entirely adequate in capturing the impact of OCD on QoL. Nonetheless, the results of this paper do suggest a significant impact. Use of QoL measures in clinical settings will provide patients with an opportunity to express their concerns and assist clinicians to evaluate the effectiveness of management beyond the clinical outcomes. This paper also highlights the lack of a disease-specific QOL instrument and the importance of developing a validated measure to assess QOL in OCD, enabling comparison across countries and occupational groups.

Evidence-based guidelines for the prevention, identification and management of occupational contact dermatitis and urticaria

BACKGROUND

Occupational contact dermatitis is the most frequently reported work-related skin disease in many countries. A systematic review was commissioned by the British Occupational Health Research Foundation in response to a House of Lords Science and Technology Committee recommendation.

OBJECTIVES

The systematic review aims to improve the prevention, identification and management of occupational contact dermatitis and urticaria by providing evidence-based recommendations.

METHODS

The literature was searched systematically using Medline and Embase for English-language articles published up to the end of September 2009. Evidence-based statements and recommendations were graded using the Royal College of General Practitioner's three-star system and the revised Scottish Intercollegiate Guidelines Network grading system.

RESULTS

Three thousand one hundred and fifty-five abstracts were identified and screened. From these, 786 full papers were obtained and appraised. One hundred and nineteen of these studies were used to produce 36 graded evidence statements and 10 key recommendations.

CONCLUSIONS

This evidence review and its recommendations focus on interventions and outcomes to provide a robust approach to the prevention, identification and occupational management of occupational contact dermatitis and urticaria, based on and using the best available medical evidence.

Occupational contact dermatitis in Australia: diagnostic and management practices, and severity of worker impairment

The aims of this study were to compare treatment and referral practices between general practitioners (GPs) and dermatologists and to evaluate predictors for occupational contact dermatitis (OCD) disease severity measured in terms of worker impairment. Data were collected from 181 patients recruited for a larger study of OCD. Information about treatment recommendations and usual referral practices are reported for 123 patients. Data from patients, diagnosed with work-related skin disease, were modelled for severity of worker impairment. GPs were more likely to treat a patient independently, referring if the patient did not improve, whereas dermatologists were more likely to refer for patch testing on initial presentation. Dermatologists were more likely to recommend gloves and GPs were more likely to recommend soap avoidance/substitution. 2 GPs and no dermatologists reported recommending the best practice combination of moisturizers, topical corticosteroids and soap substitutes. When adjusted for all variables including age, sex, duration and diagnostic subgroup, workers with atopy as a cofactor had the most severe impairment. This study suggests that in Australia, patients with suspected OCD are initially managed within general practice, few clinicians recommend best practice treatments for OCD, and that atopy is associated with severity. These findings have implications for health resource allocation, clinician education, and the pre-employment counselling of atopic patients.

Concomitant contact allergy to the resins, reactive diluents and hardener of a bisphenol A/F-based epoxy resin in subway construction workers

An outbreak of suspected contact dermatitis among subway construction workers was suspected to be due to a new bisphenol A/F-based epoxy resin system (ERS). The construction workers used ERSs during the insertion of iron bars into concrete walls. The objective of the study was to determine the components (if any) of the ERS responsible for the contact allergy. Patch testing was performed on 20 of the 22 construction workers who had had contact with the ERS, and to the various subcomponents of component A on 5 of the 7 who reacted to this component. 9 patients (9/22, 40.9%) had clinical symptoms and signs of suspected contact dermatitis at presentation. 7 of these 9, but none of the 11 asymptomatic individuals, were positive to component A, while all were negative to component B. Of the 5 cases receiving further patch testing, all reacted to m-xylylene diamine, 4 to 1,6-hexanediol diglycidyl ether, 3 to epoxy resins of the bisphenol F-type and trimethylolpropane triglycidyl ether 0.25% petrolatum, and only 1 to epoxy resins of the bisphenol A-type. Contact allergy to ERSs may involve hardeners and diluents as well as resins, and patch testing for reaction to all components should be performed.