Triphenylguanidine, a new (old?) rubber accelerator detected in surgical gloves that may cause allergic contact dermatitis

Presence of 1, 3-Diphenylguanidine and Its Derivatives in Human Urine and Their Human Exposure

Recent studies have demonstrated the widespread presence of 1,3-diphenylguanidine (DPG) and its derivatives in environmental matrices. While, the amount of human exposure to these rubber additives remains unclear. In this study, we collected human urine samples from healthy general adults (n = 221) living in Quzhou, China, and analyzed these samples for DPG and its five derivatives. DPG, 1,6-bis(cyano-guanidino)hexane (HCG), 1,3-di-o-tolylguanidine (DTG) and exhibited detection frequencies exceeding 50% in collected human urine. Presence of HCG, 1-(o-tolyl)biguanide (detection frequency 17%), and 1-(4-cyanophenyl)guanidine (6.0%) in human urine was also demonstrated for the first time. The highest mean human urinary concentration was found for DPG (0.89 ng/mL, < LOD-4.7 ng/mL), followed by DTG (0.57 ng/mL, < LOD-3.1 ng/mL) and HCG (0.34 ng/mL, < LOD-1.8 ng/mL). Male participants had consistently higher average human urinary levels of DPG, DTG, and HCG than female subjects, but none of these differences were significant (p > 0.10). DPG and DTQ consistently showed a decline in the human urinary concentrations as age of the participant increased. DPG (mean 170 ng/kg bw/day, median 137 ng/kg bw/day) had the highest human daily exposure amount, followed by DTG (106 ng/kg bw/day, 91 ng/kg bw/day) and HCG (58 ng/kg bw/day, 38 ng/kg bw/day). The study enhances our understanding of human exposure to these rubber additives, which is crucial for assessing their potential health risks.

Occurrence, sources, and human exposure assessment of amine-based rubber additives in dust from various micro-environments in South China

Despite the ubiquitous use and potential health effects of amine-based rubber additives, information regarding their occurrences in indoor environments remains scarce and is basically investigated in traffic-related environments. In this study, a total of 140 dust samples collected from eight indoor micro-environments were analyzed for twelve amine-based rubber additives. Overall, 1,3-diphenylguanidine (DPG), dicyclohexylamine (DCHA), N-(1,3-dimethylbutyl)-N'-phenyl-p-penylenediamine (6PPD), 6PPD-quinone (6PPDQ), and hexa(methoxymethyl)melamine (HMMM) were frequently detected across all micro-environments with detection frequencies of 97 %, 51 %, 71 %, 99 %, and 77 %, respectively. The highest total concentration of amine-based rubber additives was found in parking lots (median 10,300 ng/g), indicating heavier emission sources of these compounds in vehicle-related indoor environments. Despite this, amine-based rubber additives were also frequently detected in various non-vehicle-related environments, such as markets, cinemas, and hotels, probably due to the widespread use of consumer products and more frequent air exchanges with outdoor environments. Further tracking of tire rubber products and paint particles from flooring materials in parking lots revealed that paint particles might be an overlooked contributor to amine-based rubber additives in indoor environments. Finally, the highest estimated daily intakes (EDIs) of all amine-based rubber additives via dust ingestion at home were observed for toddlers (3.48 ng/kg bw/d). This research provides a comprehensive overview of human exposure to a variety of amine-based rubber additives in various indoor environments. ENVIRONMENTAL IMPLICATION: This study highlights the presence of high concentrations of amine-based additives in indoor dust from both traffic-related and non-traffic-related indoor environments. Additional efforts are needed to identify potential sources of amine-based rubber additives indoors, beyond just tire rubber. This is critical because the widespread presence of rubber products in indoor settings could pose a risk to human health.

Contents of sensitising rubber accelerators in disposable rubber gloves: A Copenhagen market survey

BACKGROUND

Rubber gloves contain rubber accelerators that may cause contact allergy. The content of sensitising rubber accelerators in contemporary rubber gloves is not well known.

OBJECTIVES

Identify and quantify the content of rubber accelerators in disposable rubber gloves.

METHODS

Fifty-one gloves of 49 different brands were collected. Forty-eight of the gloves were disposable and three re-usable. The gloves were analysed for their content of sensitising rubber accelerators, that is, zinc dithiocarbamates, thiurams, thiazoles/benzothiazoles, diphenylguanidine, and thioureas by high-performance liquid chromatography.

RESULTS

Rubber accelerators were identified in 43/48 (90%) of the disposable gloves. In total, 39 gloves contained zinc dibutyldithiocarbamate (ZDBC) (0.18-1.96 mg/g), 34 zinc diethyldithiocarbamate (ZDEC) (0.032-2.78 mg/g), three zinc dibenzyldithiocarbamate (0.65-1.4 mg/g), one zinc dimethyldithiocarbamate (0.23 mg/g), and one 1,3-diphenylguanidine (0.21 mg/g). 2-cyanoethyl dimethyldithiocarbamate (CEDMC) was identified in three gloves (<0.052 mg/g). The one glove labelled as accelerator free contained ZDBC (1.07 mg/g). Only few glove packages had the specific content of rubber accelerators labelled.

CONCLUSIONS

The most frequent rubber accelerators in rubber gloves are ZDEC and ZDBC. Accelerator-free gloves may contain rubber accelerators. Full labelling of rubber gloves is needed and producers should be sure not to falsely claim that the rubber gloves are free of rubber accelerators.

Potential for Glove Risk Amplification via Direct Physical, Chemical, and Microbiological Contamination

This review focuses on the potential direct physical, chemical, and microbiological contamination from disposable gloves when utilized in food environments, inclusive of the risks posed to food products as well as worker safety. Unrecognized problems endemic to glove manufacturing were magnified during the COVID-19 pandemic due to high demand, increased focus on PPE performance, availability, supply chain instability, and labor shortages. Multiple evidence-based reports of contamination, toxicity, illness, deaths, and related regulatory action linked to contaminated gloves in food and healthcare have highlighted problems indicative of systemic glove industry shortcomings. The glove manufacturing process was diagramed with sources and pathways of contamination identified, indicating weak points with documented occurrences detailed. Numerous unsafe ingredients can introduce chemical contaminants, potentially posing risks to food and to glove users. Microbial hazards present significant challenges to overall glove safety as contaminants appear to be introduced via polluted water sources or flawed glove manufacturing processes, resulting in increased risks within food and healthcare environments. Frank and opportunistic pathogens along with food spoilage organisms can be introduced to foods and wearers. When the sources and pathways of glove-borne contamination were explored, it was found that physical failures play a pivotal role in the release of sweat build-up, liquefaction of chemical residues, and incubation of microbial contaminants from hands and gloves. Thus, with glove physical integrity issues, including punctures in new, unused gloves that can develop into significant rips and tears, not only can direct physical food contamination occur but also chemical and microbiological contamination can find their way into food. Enhanced regulatory requirements for Acceptable Quality Limits of food-grade gloves, and the establishment of appropriate bioburden standards would enhance safety in food applications. Based on the information provided, together with a false sense of security associated with glove use, the unconditional belief in glove chemical and microbiological purity may be unfounded.

1,3-Diphenylguanidine, benzothiazole, benzotriazole, and their derivatives in soils collected from northeastern United States

1,3-Diphenylguanidine (DPG), benzothiazole (BTH), benzotriazole (BTR), and their derivatives are high-production-volume chemicals widely used in tires, corrosion inhibitors and plastic products. Vehicular traffic is an important source of these chemicals in the environment. Despite this, little is known about the occurrence of these chemicals in roadside soils. In this study, we determined the concentrations, profiles, and distribution patterns of 3 DPGs, 5 BTHs, and 7 BTRs in 110 soil samples collected from northeastern United States. We found widespread occurrence of 12 out of the 15 analytes measured in roadside soils, at detection frequencies ≥71 % and median concentrations in the range of 0.38-380 ng/g (dry weight). DPGs were the predominant chemicals accounting for 63 % of the sum concentrations of three chemical classes determined, followed by BTHs (28 %) and BTRs (9 %). The concentrations of all analytes (except for 1-, 4-, and 5-OH-BTRs) exhibited significant positive correlations (r: 0.1-0.9, p < 0.01), suggestive of their common sources and/or similar environmental fates. Higher concentrations of DPGs, BTHs and BTRs were found in soils from highways, rubberized playgrounds, and indoor parking lots than those from gardens, parks, and residential areas. Our findings suggest the release of DPGs, BTHs and BTRs from rubber products, especially automobile tires. Further studies are needed to investigate the environmental fate and toxicities of these chemicals to humans and wildlife.

Occurrence of 1,3-Diphenylguanidine, 1,3-Di-o-tolylguanidine, and 1,2,3-Triphenylguanidine in Indoor Dust from 11 Countries: Implications for Human Exposure

1,3-Diphenylguanidine (DPG), 1,3-di-o-tolylguanidine (DTG), and 1,2,3-triphenylguanidine (TPG) are synthetic chemicals widely used in rubber and other polymers. Nevertheless, limited information is available on their occurrence in indoor dust. We measured these chemicals in 332 dust samples collected from 11 countries. DPG, DTG, and TPG were found in 100%, 62%, and 76% of the house dust samples, at median concentrations of 140, 2.3, and 0.9 ng/g, respectively. The sum concentrations of DPG and its analogues varied among the countries in the following decreasing order: Japan (median: 1300 ng/g) > Greece (940) > South Korea (560) > Saudi Arabia (440) > the United States (250) > Kuwait (160) > Romania (140) > Vietnam (120) > Colombia (100) > Pakistan (33) > India (26). DPG accounted for ≥87% of the sum concentrations of the three compounds in all countries. DPG, DTG, and TPG exhibited significant correlations (r: 0.35-0.73; p < 0.001). Elevated concentrations of DPG were found in dust from certain microenvironments (e.g., offices and cars). Human exposure to DPG through dust ingestion were in the ranges 0.07-4.40, 0.09-5.20, 0.03-1.70, 0.02-1.04, and 0.01-0.87 ng/kg body weight (BW)/day for infants, toddlers, children, teenagers, and adults, respectively.

COVID-19: An overview for dermatologists

Numerous unexplained pneumonia cases were reported to the World Health Organization (WHO) by Wuhan, China, in December 2020. Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), a zoonotic pathogen, came into sight, spreading coronavirus disease 2019 (COVID-19) all over the globe. Association of cutaneous signs and symptoms with COVID-19 is being studied worldwide, principally, to determine if these dermatoses can help in early recognition of SARS-CoV-2 infection. These dermatological manifestations can range from erythematous rash, urticaria to livedo reticularis, and acrocyanosis in patients of all age groups. Correspondingly, dermatologists treating COVID-19 patients, suffering from inflammatory dermatoses, with biologics or immunomodulators should exert caution and use specific protocols to adjust the doses of these medications. Prevention of person-to-person transmission of COVID-19 is being promoted universally, with the use of personal protective equipment (PPE), hand washes, and hand sanitizers around the clock. However, an array of cutaneous adverse effects such as contact dermatitis, irritant contact dermatitis, friction blisters, contact urticaria, acne, and infections are associated with the use of PPE. Extra-pulmonary manifestations of COVID-19 are still emerging in the community, and physicians and researchers are working together globally to strengthen the clinical management of these patients. Cases of COVID-19 continue to rise across the world, and an unprecedented approach has been taken to develop effective vaccines and therapeutic strategies against existing and forthcoming mutagenic strains of SARS-CoV-2.

Making Glove Decision Less of a White Knuckling Experience: A Systematic Review and Inventory of Glove Accelerator Contents

Background

Accelerators in medical gloves are a common cause of allergic contact dermatitis among healthcare workers.

Objective

A systematic review of medical and nursing literature, patch testing reports, and chemical analyses of gloves was conducted to assess accelerator contents reported in the literature and to identify accelerator-free gloves.

Methods

A systematic literature search was performed in OVID Medline and OVID EMBASE. Hand-searching of reference lists of articles in the field and author input generated the remainder of articles assessed.

Results

We present an inventory of accelerator contents of gloves and accelerator-free glove options as reported in the literature as a clinical reference tool to assist allergen-free glove selection for individuals suffering from allergic contact dermatitis due to rubber accelerators.

Limitations

Pertinent limitations of our review include lack of predefined study exclusion criteria and screening of the studies identified in the search by 1 review author only.

Conclusion

The glove inventory we provide summarizes the available literature regarding medical and surgical glove accelerator content, describing gloves both by brand and manufacturer as well as by accelerators.

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.

Skin exposure to the rubber accelerator diphenylguanidine in medical gloves-An experimental study

BACKGROUND

Dermatitis caused by occupational contact allergy to rubber additives such as diphenylguanidine (DPG) in medical gloves is a hazard for healthcare workers. Both the duration of exposure to medical gloves and the number of gloves used per day vary. The use of alcoholic skin disinfectants before glove donning is mandatory.

OBJECTIVES

To assess whether skin exposure to the rubber accelerator DPG released from glove material is influenced by alcoholic hand disinfectants, time, and pH.

METHODS

With the use of ethanol washes, the amount of DPG left on the hands after wearing of gloves for 60 minutes was measured, and comparisons between hands exposed and not exposed to alcoholic disinfectant before glove donning were made. With the use of artificial sweat buffered at pH 4, 5, and 6, DPG release from the insides of gloves at different times was measured.

RESULTS

The use of alcoholic disinfectant prior to polyisoprene glove donning increased the amount of DPG recovered from the hands. Of the DPG released from polyisoprene gloves into artificial sweat, almost 84% was released within 10 minutes. pH did not influence the rate of release.

CONCLUSIONS

The use of alcoholic disinfectant increased skin exposure to the rubber accelerator DPG. Even a short duration of use of gloves results in substantial exposure to DPG.

Glove-Related Allergic Contact Dermatitis

Hand dermatitis is a common condition with a lifetime prevalence of 20%. Glove allergic contact dermatitis (ACD) is a very important dermatitis affecting health care workers, hairdressers, cleaning personnel, kitchen workers, craftsmen, construction workers, laboratory workers, and homemakers. Occupationally related cases may be severe and can result in significant disability. Glove ACD is most commonly due to exposure to rubber accelerators, which are compounds that are added to rubber during production to increase strength and durability. Given the known allergic potential of these compounds, glove manufacturing companies have reformulated gloves leading to the introduction of new rubber allergens. In this review, we will discuss risk factors for glove ACD, both common and uncommon allergens in gloves, common contact allergens that permeate gloves, and patch testing to help uncover the inciting allergen(s).

New Contact Allergens: 2008 to 2015

Every year, new contact allergens, chemicals reported to have caused contact allergy/ACD for the first time, are described in literature. In the journals Contact Dermatitis and Dermatitis, 172 such compounds were identified in the period 2008-2015, 119 of which induced ACD. These are presented with the following data: name, synonyms, Chemical Abstracts Service (CAS) number, patch test data, function or class, causative product, number of patients, occupation (in case of occupational ACD), additional clinical data (if applicable), and references. Approximately one third of the new allergens were ingredients of cosmetics, followed by drugs causing occupational ACD (18%), chemicals in rubber, plastics, and paints (9%), drugs causing a drug eruption (9%), as well as chemicals used in laboratories inducing occupational ACD (8%). In 40%, the dermatitis was occupationally acquired. Fifty-three other chemicals causing contact allergy as indicated by positive patch test reactions only are shown without specifics.

Recent Trends in Occupational Contact Dermatitis

Occupational contact dermatitis (OCD) remains prevalent among workers and impacts quality of life and workability. The purpose of this review is to summarize the recent advances in occupational contact dermatitis as well as potential hazardous agents in the workplaces causing OCD. The review covers new developments in the epidemiology, etiology, diagnosis, and management of occupational contact dermatitis. This article also provides updated information on the prevalence of work-related skin symptoms and on new contact allergens among working population. It is emphasized that in the context of prevention of OCD, special attention should be focused on the identified high-risk occupational groups, especially healthcare workers and hairdressers starting with the apprentices. Current approaches include working out the standards and guidelines to improve the education, knowledge, diagnosis, and management of OCD based on a multidisciplinary team of medical specialists and an employer.