Dermatitis among automobile production machine operators exposed to metal-working fluids

The Effects of Smoking on the Severity of Atopic Dermatitis in Saudi Arabia

Background Atopic dermatitis (AD) is a well-known inflammatory skin disease that is associated with a family history of other atopic diseases. Tobacco smoking has been found to affect AD as well as several other inflammatory skin diseases. In this study, we aimed to investigate this association and to elucidate the link between dose-dependent tobacco exposure and symptom severity. Methods This cross-sectional study was conducted on individuals from the general population of Riyadh, Saudi Arabia. Data were collected using an online questionnaire. All statistical analyses were performed using RStudio, version 1.1.363 (RStudio, PBC, Boston, Massachusetts, United States). Questions about the participants' age, sex, and occupational status were included. The participants were asked to report their daily handwashing habits and history of atopic diseases. Data on the smoking duration, number of cigarettes smoked per day, and passive exposure were collected. Results A total of 510 participants (41.3 %) reported having AD. Smoking was significantly associated with an increased prevalence of AD. The odds of having AD were 1.78 and 2.27 times higher in occasional smokers (odds ratio (OR) = 1.78, p < 0.05) and daily smokers (OR = 2.27, p < 0.001) than in non-smokers. Neither smoking frequency (p = 0.19) nor duration (p = 0.73) was significantly associated with AD prevalence. Conclusion Smoking is significantly associated with an increased prevalence of AD. Adults should be discouraged from smoking in order to prevent adult-onset AD. The level of nicotine exposure should be measured objectively in future studies.

Risk Assessment for Metalworking Fluids and Respiratory Outcomes

Background

Metalworking fluids (MWFs) are mixtures with inhalation exposures as mists, dusts, and vapors, and dermal exposure in the dispersed and bulk liquid phase. A quantitative risk assessment was performed for exposure to MWF and respiratory disease.

Methods

Risks associated with MWF were derived from published studies and NIOSH Health Hazard Evaluations, and lifetime risks were calculated. The outcomes analyzed included adult onset asthma, hypersensitivity pneumonitis, pulmonary function impairment, and reported symptoms. Incidence rates were compiled or estimated, and annual proportional loss of respiratory capacity was derived from cross-sectional assessments.

Results

A strong healthy worker survivor effect was present. New-onset asthma and hypersensitivity pneumonitis, at 0.1 mg/m³ MWF under continuous outbreak conditions, had a lifetime risk of 45%; if the associated microbiological conditions occur with only 5% prevalence, then the lifetime risk would be about 3%. At 0.1 mg/m³, the estimate of excess lifetime risk of attributable pulmonary impairment was 0.25%, which may have been underestimated by a factor of 5 or more by a strong healthy worker survivor effect. The symptom prevalence associated with respiratory impairment at 0.1 mg/m³ MWF was estimated to be 5% (published studies) and 21% (Health Hazard Evaluations).

Conclusion

Significant risks of impairment and chronic disease occurred at 0.1 mg/m³ for MWFs in use mostly before 2000. Evolving MWFs contain new ingredients with uncharacterized long-term hazards.

The association of smoking with contact dermatitis and hand eczema - a review

Given the high prevalence of allergic contact dermatitis (ACD), irritant contact dermatitis (ICD), hand eczema (HE), and smoking, and the impact that smoking has on skin disease, the authors reviewed the existing literature to assess the association between smoking and contact dermatitis or hand eczema. Using the PubMed and SCOPUS databases, a literature search identified articles related to allergic contact dermatitis, irritant contact dermatitis, and hand eczema and a possible association with smoking. The search period included articles prior to and including April 2016. Seven of eight articles described a positive relationship between smoking and allergic or irritant contact dermatitis, while nine of nineteen articles found a positive association between smoking and hand eczema. Published studies document that smoking may be an important risk factor for both allergic and irritant contact dermatitis as well as hand eczema.

Potential health effects associated with dermal exposure to occupational chemicals

There are a large number of workers in the United States, spanning a variety of occupational industries and sectors, who are potentially exposed to chemicals that can be absorbed through the skin. Occupational skin exposures can result in numerous diseases that can adversely affect an individual's health and capacity to perform at work. In general, there are three types of chemical-skin interactions of concern: direct skin effects, immune-mediated skin effects, and systemic effects. While hundreds of chemicals (metals, epoxy and acrylic resins, rubber additives, and chemical intermediates) present in virtually every industry have been identified to cause direct and immune-mediated effects such as contact dermatitis or urticaria, less is known about the number and types of chemicals contributing to systemic effects. In an attempt to raise awareness, skin notation assignments communicate the potential for dermal absorption; however, there is a need for standardization among agencies to communicate an accurate description of occupational hazards. Studies have suggested that exposure to complex mixtures, excessive hand washing, use of hand sanitizers, high frequency of wet work, and environmental or other factors may enhance penetration and stimulate other biological responses altering the outcomes of dermal chemical exposure. Understanding the hazards of dermal exposure is essential for the proper implementation of protective measures to ensure worker safety and health.

Skin absorption of six performance amines used in metalworking fluids

Every year, 10 million workers are exposed to metalworking fluids (MWFs) that may be toxic. There are four types of MWFs: neat oils and three water-based MWFs (soluble oil, semisynthetic and synthetic), which are diluted with water and whose composition varies according to the mineral oils ratio. MWFs also contain various additives. To determine the absorption of six amines used as corrosion inhibitors and biocides in MWFs, porcine skin flow-through diffusion cell experiments were conducted with hydrophilic ethanolamines (mono-, di- and triethanolamine, MEA, DEA and TEA respectively) and a mixture of lipophilic amines (dibutylethanolamine, dicyclohexylamine and diphenylamine). The six amines were dosed in four vehicles (water and three generic water-based MWF formulations) and analyzed using a scintillation counter or gas chromatography/mass spectrometry. These 24 h studies showed that dermal absorption significantly (P < 0.05) increased from water for the six amines (e.g. 1.15 ± 0.29% dose; DEA in water) compared to other formulations (e.g. 0.13 ± 0.01% dose; DEA in semisynthetic MWF) and absorption was greatest for dibutylethanolamine in all the formulations. The soluble oil formulation tended to increase the dermal absorption of the hydrophilic amines. The permeability coefficient was significantly higher (P < 0.05) with TEA relative to the other hydrophilic amines (e.g. 4.22 × 10(-4) ± 0.53 × 10(-4) cm h(-1) [TEA in synthetic MWF] vs. 1.23 × 10(-4) ± 0.10 × 10(-4) cm h(-1) [MEA in synthetic MWF]), except for MEA in soluble oil formulation. Future research will confirm these findings in an in vivo pig model along with dermatotoxicity studies. These results should help MWF industries choose safer additives for their formulations to protect the health of metalworkers.

Occupational skin diseases in automotive industry workers

CONTEXT

Studies on occupational skin diseases in workers of the automotive industry are few.

AIM

To investigate the prevalence of occupational skin diseases in workers of the automotive industry.

MATERIALS AND METHODS

Between September and December 2011, a total of 405 workers from the automotive repair industry in Diyarbakır were interviewed. They were active workers in the repair industry who had been employed for at least six months. Business owners, sellers of spare parts and accounting officers were not included. The employees were examined at their workplaces and the working conditions were observed. Detailed dermatological examination was performed.

RESULTS

The mean age of the 405 workers who participated in the study was 27.7 ± 10.3. The mean working time of employees was 13.3 ± 10.4 years. All of the employees were male. Dermatological diseases were not detected in 144 out of 405 workers (35.6%) and at least one condition was diagnosed in 261 (64.4%). The most frequent diagnosis was callus, hyperkeratosis, clavus (27.7%), followed by nail changes (16.8%) and superficial mycoses (12.1%). Contact dermatitis was seen at a rate of 5.9%.

DISCUSSION

Traumatic lesions such as hyperkeratotic lesions and nail changes were found most frequently. Traumatic lesions were common among individuals who did not use gloves. Most nail changes were localized leuconychia, a finding not reported in the studies on automotive industry workers. In accordance with the literature, irritant contact dermatitis was observed in patients with a history of atopy and who had been working for a long time.

CONCLUSION

Occupational skin diseases comprise an important field in dermatology, deserving much attention. Further studies on occupational dermatology are necessary.

Occupational respiratory and skin diseases among Finnish machinists: findings of a large clinical study

PURPOSE

Machinists are exposed to many sensitizing and irritant substances, but no previous study has assessed the occurrence of clinically verified occupational diseases in an unselected large workforce of machinists. Our aim was to study the occurrence of clinically verified occupational respiratory and skin diseases cross-sectionally in a large sample of machinists in southern Finland.

METHODS

A computer-assisted telephone interview on occupational exposures and health was carried out in a sample of 961 machining workers from 64 metalworking companies. Of these, 757 (79%) answered the interview. A total of 245 subjects reported work-related respiratory or skin symptoms and were invited to clinical examinations; 138 of these underwent a clinical interview and examination by an occupational health physician. On the basis of this examination, 32 subjects were further examined at the Finnish Institute of Occupational Health (FIOH) for occupational skin or respiratory diseases.

RESULTS

One case of occupational asthma (OA) and seven cases of occupational dermatoses (OD) were diagnosed, giving a prevalence of 0.13% (95% CI 0-0.39) for OA, and 0.92% (95% CI 0.24-1.16) for OD. The OA was induced by the patient's own MWF. Additional five cases of newly diagnosed non-occupational asthma (0.79%, 95% CI = 0.16-1.42) were detected. No cases of occupational rhinitis or COPD were diagnosed. The dermatoses diagnoses consisted of four cases of allergic contact dermatitis and three cases of irritant contact dermatitis. The most common causes of the ODs were MWFs.

CONCLUSION

This large clinical study of machinists representing metalworking in South Finland showed a prevalence of 0.13% of OA and 0.92% of OD. This relatively low occurrence of occupational diseases may reflect the strict Finnish criteria for the diagnosis of these occupational diseases and the relatively good level of occupational hygiene in machining workshops in Finland. Reported respiratory and skin symptoms were common, and these milder conditions may be linked to irritant rather than sensitizing exposures.

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.

Tobacco and the skin

Smoking negatively impacts the health of the skin as it does every organ system. This contribution reviews the effect of cigarette smoking on wound healing, wrinkling, and aging of the skin, skin cancer, psoriasis, and other inflammatory skin diseases, hidradenitis suppurativa, acne, alopecia, lupus erythematosus, polymorphous light eruption, and tobacco-associated oral lesions. Dermatologists need to encourage their patients to discontinue this deleterious habit.

In vitro dermal penetration of 4-chloro-3-methylphenol from commercial metal working fluid and aqueous vehicles

The biocide 4-chloro-3-methylphenol (CMP, CAS number 59-50-7) is a common additive to metal-working fluids (MWF) and building materials. National Institute for Occupational Safety and Health (NIOSH) researchers previously identified and quantified CMP in a commercial water-soluble MWF, TRIM VX, and demonstrated irritancy and sensitization potential of both TRIM VX and CMP alone after dermal exposure in a murine model. In the current study, the in vitro human epidermal permeability of CMP contained in a working dilution of TRIM VX (20% in water) was evaluated and, for comparison, permeability from an aqueous buffer was also assessed. CMP penetration was also measured from transient exposures to 20% TRIM VX. To address differences in penetration rates from 20% TRIM VX and from buffer, the role of thermodynamic activity of CMP in the 2 vehicles on dermal penetration was investigated. Static headspace gas chromatography was used to measure vapor pressures and infer fractional thermodynamic activities of CMP in the mixtures. Permeability coefficient (k(p)) of CMP from 20% TRIM VX was (4.1 +/- 0.8) x 10(-3) cm/h (mean +/- SD, n = 5), and CMP was found at a concentration of 3555 +/- 191 microg/ml in this donor. In contrast, k(p) was 0.18 +/- 0.03 cm/h (n = 5) at a similar concentration (3919 +/- 240) from buffer donor. Steady-state fluxes from 20% TRIM VX and buffer were comparable when expressed as functions of thermodynamic activity of CMP in the donor, rather than as concentrations. Transient (20 or 40 min) exposures of epidermal membranes to 20% TRIM VX (n = 4) resulted in total penetration of 4.2 +/- 1.2 and 7.3 +/- 0.8 microg/cm(2), respectively; these amounts are comparable to amounts predicted using a simple algebraic equation.

Evaluation of irritancy and sensitization potential of metalworking fluid mixtures and components

There are approximately 1.2 million workers exposed to metalworking fluids (MWF), which are used to reduce the heat and friction associated with industrial machining and grinding operations. Irritancy and sensitization potential of 9 National Toxicology Program (NTP) nominated MWFs (TRIM 229, TRIM VX, TRIM SC210, CIMTECH 310, CIMPERIAL 1070, CIMSTAR 3800, SYNTILO 1023, SUPEREDGE 6768, and CLEAREDGE 6584) were examined in a combined local lymph node assay (LLNA). BALB/c mice were dermally exposed to each MWF at concentrations up to 50%. Significant irritation was observed after dermal exposure to all MWFs except CIMTECH 310 and SYNTILO 1023. Of the 9 MWFs, 6 induced greater than a 3-fold increase in lymphocyte proliferation and 7 tested positive in the irritancy assay. TRIM VX yielded the lowest EC3 value (6.9%) with respect to lymphocyte proliferation. Chemical components of TRIM VX identified using HPLC were screened for sensitization potential using structural activity relationship (SAR) modeling and the LLNA. TOPKAT predicted triethanolamine (TEA) as a sensitizer while Derek for Windows predicted only 4-chloro-3-methylphenol (CMP) to be positive for sensitization. When tested in the LLNA only CMP (EC3 = 11.6%) and oleic acid (OA) (EC3 = 29.7%) were identified as sensitizers. Exposure to all tested TRIM VX components resulted in statistically significant irritation. An additive proliferative response was observed when mixtures of the two identified sensitizing TRIM VX components, OA and CMP, were tested in the LLNA. This is one explanation of why the EC3 value of TRIM VX, with respect to lymphocyte proliferation, is lower than those assigned to its sensitizing components.

Contact dermatitis in car repair workers

BACKGROUND

Occupational contact dermatitis (OCD) is a common skin disorder with a poor prognosis.

OBJECTIVES

The objectives of this study were to (1) estimate the prevalence of CD among car repair workers, (2) study some risk factors associated with CD, and (3) conduct an intervention skin care education program.

SUBJECTS AND METHODS

A cross-sectional study was conducted in 87 car repair workers with regular and direct exposure to chemicals at the industrial zone in Zagazig City, Egypt and 76 unexposed assembly booksellers. All workers were subjected to a questionnaire and clinical examination, and those who were diagnosed clinically as CD were patch tested. Intervention study with a skin care education program was carried out on 47 car repair workers. Re-evaluation of the intervention group after 5 months was done.

RESULTS

The total prevalence of CD among car repair workers (18.4%) was significantly higher compared with their controls (3.9%), with the highest prevalence among car mechanics (24.1%) and painters (20.7%); 16.1% of them reported recurrent dermatitis in the last 12 months. Nickel accounted for most positive patch test reactions (33.3%). A significant association was noticed between the prevalence of CD and age, smoking, atopic background and duration of work. After the intervention study, a significantly higher knowledge level about CD was reported.

CONCLUSION

The most important risk factors for OCD among the car repair workers are atopic background and long duration of work. Skin care education program is an important tool for prevention of CD and control of exposure to substances hazardous to the skin.

Self-reported skin symptoms in metal workers

Machinists and machine maintenance men working in the metal industry use metal-working fluids capable of causing irritant and allergic contact dermatitis. The objectives of this study were to find out the frequency of skin symptoms in machinists and machine maintenance men (metal workers) and to compare the risk of their skin symptoms to that in office workers (controls). A total of 726 male metal workers and 84 controls answered a structured telephone questionnaire enquiring about work, atopy, skin symptoms, their impact on life, etc. The risk of skin symptoms compared with that in the controls was estimated using a logistic regression analysis. Of the metal workers, 20% reported recurring or prolonged dermatitis on their hands or forearms during the past 12 months. The hand or forearm dermatitis (HD) affected mostly the metal workers' mood and their activities at work. Recurring dermatitis elsewhere (DE) than in the hands and in connection with work was reported by 10%. The risk of HD was about twofold and the risk of DE was about fourfold compared with that in the controls. The HD of machinists may be severe and affect their ability to work. DE may have clinical significance in machinists.

Evaluation of 2 self-administered questionnaires to ascertain dermatitis among metal workers and its relation with exposure to metalworking fluids

We performed an exploratory study to evaluate 2 self-administered questionnaires assessing hand dermatitis and investigate a possible exposure-response relationship between dermal exposure to semi-synthetic metalworking fluids (SMWF) and dermatitis. In a cross-sectional survey on dermatitis, a symptom-based questionnaire and a picture-based skin screening list were applied in 80 SMWF-exposed workers and 67 referents. To evaluate the accuracy of the questionnaires, 47 subjects were examined by a dermatologist. Dermal exposure levels to SMWF were assessed on hands, forearms, and face with a observational method that was validated using a fluorescent tracer method. The symptom-based questionnaire had a relatively high sensitivity (0.86) but moderate specificity (0.64), and the skin screening list had a low sensitivity (0.36) and a relatively high specificity (0.84). The skin screening list seemed to represent the more severe cases of dermatitis and showed a significant relation with exposure for dermatitis on hands, forearms, or face. In epidemiological surveys where workers are not seen by a dermatologist, the skin screening list seems to be more appropriate to detect cases of dermatitis, as its higher specificity results in less false positives. Alternatively, it would be preferable applying the symptom-based questionnaire; workers with symptoms should be seen by a dermatologist to identify false positives.

Evaluation of two self-administered questionnaires to ascertain dermatitis among metal workers and its relation with exposure to metal working fluids

We performed an exploratory study to evaluate 2 self-administered questionnaires assessing hand dermatitis and to investigate a possible exposure-response relation between dermal exposure to semi-synthetic metal working fluids (SMWF) and dermatitis. In a cross-sectional survey on dermatitis, a symptom-based questionnaire and a picture-based skin-screening list were applied in 80 SMWF-exposed workers and 67 referents. To evaluate accuracy of the questionnaires, 47 subjects were examined by a dermatologist. Dermal exposure levels to SMWF were assessed on the hands, forearms, and face with an observational method that was validated with a fluorescent-tracer method. The symptom-based questionnaire had a relatively high sensitivity (0.86) but moderate specificity (0.64), the skin-screening list had a low sensitivity (0.36) and a relatively high specificity (0.84). The skin-screening list seemed to represent the more severe cases of dermatitis and showed a significant relation to exposure, for dermatitis on hands, forearms, or face. In epidemiological surveys where workers are not seen by a dermatologist, the skin-screening list seems to be more appropriate to detect cases of dermatitis, as its higher specificity results in less false positives. Alternatively, it would be preferable to apply the symptom-based questionnaire; workers with symptoms should be seen by a dermatologist to identify false positives.

Occupational dermatitis and allergic respiratory diseases in Finnish metalworking machinists

AIM

To investigate the incidences and trends of occupational skin diseases (OSDs) and allergic respiratory diseases (ARDs) in machinists working in the fabrication of metal products.

METHODS

Data from the Finnish Register of Occupational Diseases during 1992-2001 were analysed. Incidence rates for skin and respiratory diseases of machinists were calculated and compared to the total working population. The patients investigated at the Finnish Institute of Occupational Health in the same period were described in detail.

RESULTS

A total of 279 dermatoses and 34 ARDs were reported. Skin diseases accounted for 27% of all occupational diseases. The incidences of the skin and respiratory diseases were 1.6 and 0.2 cases per 1000 person-years, respectively. This represents a 3-fold risk for getting an OSD compared to the total working population. The number of allergic contact dermatitis (ACD) increased 3-fold during the study period. The most common causes of ACD were metalworking fluids (MWFs) and their ingredients such as formaldehyde, ethanolamines and colophony. Eighty-five per cent of ARDs were asthmas. The commonest causes of asthma were metal dusts and fumes, epoxy resins and hardeners and MWFs and their components.

CONCLUSIONS

Contact dermatitis is a common occupational health problem in metalworking machinists, whereas occupational respiratory disease is rare. Only a few specific chemicals in the metalworking have thus far been identified as respiratory allergens. Specific skin tests and inhalation challenge tests with MWFs and their ingredients are recommended if an OSD or a respiratory disease is suspected.

An assessment of dermal exposure to semi-synthetic metal working fluids by different methods to group workers for an epidemiological study on dermatitis

BACKGROUND

Assessment of exposure assessment to metal working fluids (MWF) has almost exclusively focused on inhalation exposure.

AIMS

To assess levels of, and factors affecting, dermal and inhalation exposure to semi-synthetic MWF, and to identify suitable dermal exposure grouping schemes among metal workers for an epidemiological survey on dermatitis of hands, forearms, and head.

METHODS

A cross-sectional survey was conducted in four metal working machining departments of a truck manufacturing plant, estimating dermal and inhalation exposure levels to semi-synthetic metal working fluids (SMWF) in machine operators. Dermal exposure levels to SMWF were estimated by three different methods for dermal exposure assessment (VITAE, surrogate skin pad method, and a semi-quantitative dermal exposure assessment method (DREAM)).

RESULTS

The identified factors affecting dermal exposure were similar for the three methods, although differences were found for estimated variability in dermal exposure levels between groups, within groups (among workers), and from day to day. With the VITAE method differences in exposure levels were detected between workers that were not detected with the surrogate skin pad method, and only partly with the DREAM method.

CONCLUSIONS

Considering the additional effort and costs that use of the VITAE method entailed, the observational semi-quantitative DREAM method appeared to be more efficient for grouping of dermal exposure levels for the epidemiological study on dermatitis.

Smoking might be a risk factor for contact allergy

BACKGROUND

Contact allergy is a major public health problem in industrialized countries. Hitherto, known risk factors for contact allergy have mainly included increased exposure to allergens. There are no published data on the relation between smoking and contact allergy.

OBJECTIVE

To investigate the association between smoking and contact allergy.

METHODS

The study population comprised a cross-sectional, general population-based sample of 15- to 69-year-old persons living in Copenhagen, Denmark. A total of 1056 persons (73.6% of the invited) were given a patch test (TRUE test). Contact allergy was defined as a positive patch test result to at least 1 of 23 allergens. Nickel contact allergy was defined as a positive patch test reaction to nickel. Allergic nickel contact dermatitis was defined as a history of eczema on exposure to metallic objects and a positive patch test reaction to nickel. A detailed smoking history was obtained in a questionnaire.

RESULTS

Contact allergy (adjusted odds ratio, 1.8; 95% CI, 1.2 to 2.9), nickel contact allergy (adjusted odds ratio, 2.7; 95% CI, 1.4 to 5.2), and allergic nickel contact dermatitis (adjusted odds ratio, 3.0; 95% CI, 1.5 to 6.2) were significantly associated with a smoking history of more than 15 pack-years. Moreover, these associations showed a significant dose-response relation, and they were independent of sex, age, and exposure to nickel, as reflected by a history of ear piercing.

CONCLUSIONS

These data raise the hypothesis that smoking increases the risk of contact allergy. Further epidemiologic studies and investigations into the possible mechanisms are warranted.

Enhanced oxidative stress in the skin of vitamin E deficient mice exposed to semisynthetic metal working fluids

Metal working fluids (MWFs) are widely used in industry for metal cutting, drilling, shaping, lubricating, and milling. Many occupational health concerns have arisen for workers exposed to MWFs. It has been reported earlier that occupational exposure to MWFs causes allergic and irritant contact dermatitis. Previously, we have shown that dermal exposure of female and male B6C3F1 mice to 5% MWFs for 3 months resulted in accumulation of mast cells and elevation of histamine in the skin. Topical exposure to MWFs also resulted in elevated oxidative stress in the liver of both sexes and the testes in males. The goal of this study was to evaluate whether preexisting oxidative stress in the skin exacerbated mast cell influx after MWFs treatment. Oxidative stress in the skin of B6C3F1 mice was generated by dietary vitamin E deprivation. Mice were given vitamin E deficient (5-10 i.v./kg of vitamin E) or basal (50 i.v./kg of vitamin E) diets for 34 weeks. Topical treatment with MWFs (100 microl, 30%) started after 18 weeks of alimentary vitamin E deprivation. Histology of the skin after 16 weeks of exposure to MWFs revealed a 53% increase in mast cell accumulation in vitamin E deficient diets compared to mice given a vitamin E sufficient diet. Total antioxidant reserve in skin of vitamin E deprived mice treated with MWFs was decreased by 66% as compared to those mice given a vitamin E sufficient diet. GSH and protein thiols in the dermis of vitamin E deprived mice exposed to MWFs were also decreased 39 and 42%, respectively, as compared to mice given basal diet. This study clearly delineates the role of oxidative stress in enhancing mast cell accumulation caused by topical exposure to MWFs.

Farm-related dermatoses in Iowa male farmers and wives of farmers: a cross-sectional analysis of the Iowa Farm Family Health and Hazard Surveillance Project

Agricultural workers are exposed to a variety of hazards that increase their risk for dermatitis. Nevertheless, the prevalence, patterns, and risk factors for dermatitis have not been well characterized among farmers in the United States. We assessed the prevalence and risk factors for dermatitis among 382 male farmers and 256 wives of farmers in Iowa using a cross-sectional study design. From 1992 to 1994, we collected data on potential risk factors and dermatitis. The results showed that 9.6% of male farmers and 14.4% of wives of farmers reported dermatitis during the previous 12-month period. In multivariable models, a history of allergy (odds ratio [OR], 8.2; 95% confidence interval [CI], 2.0 to 33.3) was strongly associated with dermatitis among male farmers. Among wives of farmers, some college education (OR, 3.4; 95% CI, 1.1 to 9.9) and exposure to petroleum products (OR, 3.1; 95% CI, 1.3 to 7.0) were associated with dermatitis. These results can be used to form preventive efforts in controlling farmwork-related exposures.

Elevated oxidative stress in skin of B6C3F1 mice affects dermal exposure to metal working fluid

Metal working fluids (MWFs) are widely used in industry for metal cutting, drilling, shaping, lubricating, and milling. Potential for dermal exposure to MWFs exists for a large number of men and women via aerosols and splashing during the machining operations. It has been reported earlier that occupational exposure to MWFs causes allergic and irritant contact dermatitis. Previously, we showed that dermal exposure of female and male B6C3F1 mice to 5% MWFs for 3 months resulted in accumulation of mast cells and elevation of histamine in the skin. Topical exposure to MWF also resulted in elevated oxidative stress in the liver of both sexes and the testes in males. The goal of this study was to evaluate the interaction between oxidative stress in the skin and topical application of MWF. Oxidative stress in skin ofB6C3F1 mice of both sexes was generated by intradermal injection ofthe hydrogen peroxide (H2O2) -producing enzyme, glucose oxidase with polyethylene glycol (GOD+PEG). In mice given GOD+PEG, topical treatment with MWF (200 microl, 30%, for 1, 3, or 7 days) resulted in a mixed inflammatory cell response, accumulation of peroxidative products, and reduction of GSH content in the skin. Such changes were not observed with MWF treatment alone. These data indicate that oxidative stress can enhance dermal inflammation caused by occupational exposure to MWF.