Reduction in the frequency of sensitization to thiurams. A result of legislation?

Update on Contact Sensitization in the Older Adult Population

BACKGROUND

Little is known about the epidemiology of allergic contact dermatitis in the aging US population.

OBJECTIVE

The aim of this study was to describe patch test results in a cohort of older adult patients evaluated in a patch testing clinic in a tertiary medical center.

METHODS

This study was a retrospective analysis of patch test results of adults 65 years and older from February 2013 to December 2019.

RESULTS

Data from a total of 169 patients 65 years and older were analyzed. Of these patients, 84.6% (143/169) had 1 or more positive reactions on patch testing, 84.6% (121/143) of which were felt to be clinically relevant and received a final diagnosis of allergic contact dermatitis. The most common allergen categories were fragrances (30.1%), preservatives (20.8%), metals (11.0%), medicaments (8.3%), and textile dyes (6.5%). The most common individual allergens were Myroxylon pereirae resin (balsam of Peru), hydroperoxide of linalool, methylisothiazolinone, nickel sulfate, and fragrance mix I. Personal products were by far the most common presumed source of allergen exposure.

CONCLUSIONS

Allergic contact dermatitis is a common diagnosis in the older adult population, and patch testing with allergen avoidance counseling can be an important diagnostic step and potential cure for this allergic condition.

Allergic contact dermatitis caused by synthetic rubber gloves in healthcare workers: Sensitization to 1,3-diphenylguanidine is common

BACKGROUND

The frequency of allergic contact dermatitis has significantly increased in healthcare workers since the transition from latex to synthetic rubber gloves, with 1,3-diphenylguanidine being identified as the most frequently implicated allergen.

OBJECTIVES

To highlight the role of 1,3-diphenylguanidine as the culprit allergen in contact allergies to synthetic rubber gloves, to propose recommendations for patch testing, and to discuss alternatives for sensitized subjects.

MATERIALS AND METHODS

Patch test data from healthcare workers who developed hand dermatitis after wearing rubber gloves and who reacted positively to glove samples and rubber additives were collected from September 2010 to December 2017 in a Belgian hospital.

RESULTS

A total of 44 caregivers were included in this study. Patch tests showed that: (a) 84% of the study population reacted positively to carba mix; (b) 86% reacted positively to 1,3-diphenylguanidine; and (c) 13 (30%) reacted positively to thiuram mix. Half of the subjects reacted positively to gloves containing 1,3-diphenylguanidine, whereas none reacted to accelerator-free gloves.

CONCLUSION

The most commonly identified allergen was 1,3-diphenylguanidine, far ahead of thiurams, which were previously described as the most sensitizing accelerators. The use of 1,3-diphenylguanidine-free gloves is recommended. No subject reacted to gloves without accelerators, thus confirming their efficiency among accelerator-sensitized patients. We recommend that 1,3-diphenylguanidine be added to the European baseline series.

Latex medical gloves: time for a reappraisal

Many hospitals have implemented policies to restrict or ban the use of devices made of natural rubber latex (NRL) in healthcare as precautionary measures against the perceived risk of NRL allergy. Changes in glove technology, progress in measuring the specific allergenic potential of gloves and a dramatic decrease in the prevalence of NRL allergies after interventions and education prompted us to revisit the basis for justifiable glove selection policies. The published Anglophone literature from 1990 to 2010 was reviewed for original articles and reviews dealing with the barrier and performance properties of NRL and synthetic gloves and the role of glove powder. The review shows that NRL medical gloves, when compared with synthetic gloves, tend to be stronger, more flexible and better accepted by clinicians. The introduction of powder-free gloves has been associated with reductions in protein content and associated allergies. Recently, new methods to quantify clinically relevant NRL allergens have enabled the identification of gloves with low allergenic potential. The use of low-protein, low-allergenic, powder-free gloves is associated with a significant decrease in the prevalence of type I allergic reactions to NRL among healthcare workers. Given the excellent barrier properties and operating characteristics, dramatically reduced incidences of allergic reactions, availability of specific tests for selection of low-allergen gloves, competitive costs and low environmental impact, the use of NRL gloves within the hospital environment warrants reappraisal.

Contact allergy to thiurams: multifactorial analysis of clinical surveillance data collected by the IVDK network

PURPOSE

To analyse the association between occupation (represented by job title) and contact allergy to thiuram vulcanising agents based on data of a clinical registry (IVDK, www.ivdk.org ).

METHODS

Clinical, demographic and allergy patch test data of all patients tested between 1992 and 2006 with the thiuram mix (1% in petrolatum) as part of the baseline series was analysed (n = 121,051). Poisson regression analysis was used to quantify the association between different occupations (and other relevant factors) and a positive patch test reaction to the thiuram mix. Furthermore, the time trend of sensitisation prevalence was analysed in high-risk occupational subgroups identified.

RESULTS

In comparison to a largely unexposed reference group (office workers and teachers), rubber manufacturers had a significantly elevated risk (prevalence ratio (PR): 5.1, 95% confidence interval (CI) 2.0-10.5). However, health care workers such as physicians and dentists (PR: 3.8, 95% CI: 3.0-4.8) or nursing staff (PR: 3.0, 95% CI: 2.5-3.6) as well as meat and fish processors (PR 3.5, 95% CI: 2.2-5.3) and cleaners (PR 3.1, 95% CI: 2.5-3.8) were found to have a high sensitisation risk as well. In case of health care workers, a significant downward trend during the study period was observed; while in food processors and cleaners, sensitisation prevalence remained largely stable.

CONCLUSION

The adjusted multifactorial analysis identified occupations yet unknown to be associated with elevated thiuram contact allergy risk, e.g., food processors and cleaners. Thus, (i) further in-depth research can be targeted and (ii) efforts to prevent sensitisation to thiurams focussed, e.g., by limiting thiuram concentrations in products to a residual level which is technically inevitable.

Associação de urticária de contato e dermatite alérgica de contato à borracha

Apresenta-se o caso de uma profissional da área da saúde que desenvolveu reação de hipersensibilidade dos tipos I e IV à borracha. O quadro clínico mostrava dermatite eczematosa no dorso das mãos. O teste de contato foi positivo para o grupo tiuram, assim como o teste aberto com fragmento de luva após exposição de 20 minutos. A dosagem de IgE sérica (Rast) mostrou-se relevante. As reações aos alérgenos da borracha são frequentes entre os profissionais da saúde, devido ao contato constante com esse material.

Chemical changes in rubber allergens during vulcanization

Allergic contact dermatitis to rubber is caused by residues of chemicals used in manufacturing a rubber product. Several different additives are used to achieve a final product of the desired characteristics. Accelerators such as thiurams, dithiocarbamates, and mercaptobenzothiazoles are often among the additives responsible for allergic reactions recognized by dermatologists. The chemistry of the vulcanization process is complicated; as it occurs at an elevated temperature with a mixture of reactive chemicals, the compositions of the initial and final products differ. This paper investigates the changes in composition of common allergens during vulcanization, doing so by chemically analysing various rubber formulations at different stages of the process. Major changes were found in which added chemicals were consumed and new ones produced. An important observation is that thiuram disulfides rarely appear in the final rubber although they may have been used as additives. Instead, thiurams are often converted to dithiocarbamates or to products formed by addition to mercaptobenzothiazole structures, if these have been used together with thiurams as accelerators.