Occupational contact dermatitis caused by aniline epoxy resins in the aircraft industry.

BACKGROUND: Tetraglycidyl-4,4'-methylenedianiline (TGMDA) is an aniline epoxy resin used in, for example, resin systems of pre-impregnated composite materials (prepregs) of the aircraft industry. Allergic contact dermatitis caused by TGMDA in prepregs has been described previously. OBJECTIVES: To report on 9 patients with occupational allergic contact dermatitis caused by TGMDA in epoxy glues used in helicopter assembly. METHODS: The patients were examined with patch testing at the Finnish Institute of Occupational Health in 2004-2009. The first patient was diagnosed by testing both components of two epoxy glues from the workplace, and was also tested with glue ingredients, including TGMDA. The following patients were tested with the glues and TGMDA. The resin parts of the glues were analysed for their epoxy compounds, including TGMDA. RESULTS: All of the patients had a patch test reaction to one or both of the resin parts of the TGMDA-containing glues. Eight of them had a strong allergic reaction to TGMDA, and one had a doubtful reaction to TGMDA. Two of the patients also had an allergic reaction to triglycidyl-p-aminophenol (TGPAP), another aniline epoxy resin, which was not present in the TGMDA-containing glues. CONCLUSIONS: In aircraft industry workers with suspected occupational dermatitis, aniline epoxy resins should be considered and patch tested as possible contact allergens.

Patch test results of the European baseline series among patients with occupational contact dermatitis across Europe - analyses of the European Surveillance System on Contact Allergy network, 2002-2010.

BACKGROUND: Occupational contact dermatitis is one of the most common occupational diseases in Europe. In order to develop effective preventive measures, detailed and up-to-date data on the incidence, main causes and professions at risk of occupational contact dermatitis are needed. OBJECTIVES: To describe the pattern of patch test reactivity to allergens in the European baseline series of patients with occupational contact dermatitis in different occupations. METHODS: We analysed data collected by the European Surveillance System on Contact Allergy (ESSCA) network from 2002 to 2010, from 11 European countries. RESULTS: Allergens in the European baseline series associated with an at least doubled risk of occupational contact dermatitis include: thiuram rubber chemical accelerators, epoxy resin, and the antimicrobials methylchloroisothiazolinone/methylisothiazolinone, methyldibromo glutaronitrile, and formaldehyde. The highest risk of occupational contact dermatitis was found in occupations classified as 'other personal services workers', which includes hairdressers, nursing and other healthcare professionals, precision workers in metal and related materials, and blacksmiths, tool-makers and related trades workers. CONCLUSIONS: In the planning and implementation of measures aimed at preventing occupational contact dermatitis, the focus should be on the identified high-risk occupational groups and the most common occupational allergies.

Contact allergy to epoxy hardeners.

BACKGROUND: Diglycidylether of bisphenol A resin is the most important sensitizer in epoxy systems, but a minority of patients develop concomitant or solitary contact allergy to epoxy hardeners. At the Finnish Institute of Occupational Health, several in-house test substances of epoxy hardeners have been tested in a special epoxy compound patch test series. OBJECTIVES: To analyse the frequency and clinical relevance of allergic reactions to different epoxy hardeners. METHODS: Test files (January 1991 to March 2013) were screened for contact allergy to different epoxy hardeners, and the clinical records of patients with allergic reactions were analysed for occupation, concomitant allergic reactions, and exposure. RESULTS: The most commonly positive epoxy hardeners were m-xylylenediamine (n = 24), 2,4,6-tris-(dimethylaminomethyl)phenol (tris-DMP; n = 14), isophorone-diamine (n = 12), and diethylenetriamine (n = 9). Trimethylhexamethylenediamine (n = 7), tetraethylenepentamine (n = 4), and triethylenetetramine (n = 2) elicited some reactions, although most patients were found to have no specific exposure. Allergic reactions to hexamethylenetetramine, dimethylaminopropylamine and ethylenediamine dihydrochloride were not related to epoxy products. CONCLUSIONS: Tris-DMP is an important sensitizer in epoxy hardeners, and should be included in the patch test series of epoxy chemicals.

Screening occupational contact allergy to bisphenol F epoxy resin.

BACKGROUND: Epoxy resins based on diglycidyl ether of bisphenol F (DGEBF) are widely used as such in applications requiring chemical resistance, and also together with diglycidyl ether of bisphenol A resin (DGEBA-R). Concomitant patch test reactions to DGEBA-R and DGEBF resin (DGEBF-R) are common. Previous studies have yielded conflicting results on the frequency of independent DGEBF-R contact allergies. OBJECTIVES: To report the results of over 11 years of screening with DGEBF-R. METHODS: An in-house test substance of DGEBF-R (Epikote 862) was tested in the baseline patch test series, first at 1% and later at 0.25%. Test files were screened for allergic reactions to DGEBF-R and DGEBA-R, and the clinical records of positively reacting patients were analysed for occupation and exposure. RESULTS: Among 1972 patients, 66 (3.3%) reacted to DGEBF-R and 96 (4.9%) to DGEBA-R. Independent DGEBF-R allergies were seen in 5 patients only, and independent DGEBA-R allergies in 35. Specific exposure to DGEBF-R was found in 26 patients. The main occupational fields were the aircraft industry, the electrical and sports equipment industry, boat building, painting/floor coating, tile setting, and pipe relining. CONCLUSIONS: Independent contact allergies to DGEBF-R were rare, and screening with it was not found to be useful.

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.

Current patch test results with the European baseline series and extensions to it from the 'European Surveillance System on Contact Allergy' network, 2007-2008.

BACKGROUND: The pattern of contact sensitization to the supposedly most important allergens assembled in the baseline series differs between countries, presumably at least partly because of exposure differences. Objectives. To describe the prevalence of contact sensitization to allergens tested in consecutive patients in the years 2007 and 2008, and to discuss possible differences. METHODS: Data from the 39 departments in 11 European countries comprising the European Surveillance System on Contact Allergy network (www.essca-dc.org) in this period have been pooled and analysed according to common standards. RESULTS: Patch test results with the European baseline series, and country-specific or department-specific additions to it, obtained in 25 181 patients, showed marked international variation. Metals and fragrances are still the most frequent allergens across Europe. Some allergens tested nationally may be useful future additions to the European baseline series, for example methylisothiazolinone, whereas a few long-term components of the European baseline series, namely primin and clioquinol, no longer warrant routine testing. CONCLUSIONS: The present analysis points to 'excess' prevalences of specific contact sensitization in some countries, although interpretation must be cautious if only few, and possibly specialized, centres are representing one country. A comparison as presented may help to target in-depth research into possible causes of 'excess' exposure, and/or consideration of methodological issues, including modifications to the baseline series.

Occupational contact allergy to monomeric isocyanates.

BACKGROUND: The monomeric isocyanates diphenylmethane diisocyanate (MDI), 2,4-toluene diisocyanate (TDI), isophorone diisocyanate (IPDI) and 1,6-hexamethylene diisocyanate (HDI) are used in polyurethane products and sometimes cause contact allergy. OBJECTIVES: To describe patients with isocyanate contact allergy in an occupational dermatology clinic. METHODS: Test files were screened for allergic reactions to isocyanates and 4,4'-diaminodiphenylmethane (MDA). Patients with allergic reactions to some of the allergens were analysed for occupation, exposure, concomitant reactions to other allergens, and diagnosis. RESULTS: Over a period of almost 13 years, 54 patients reacted to isocyanates (9 to IPDI, 12 to MDI, 6 to TDI, and 1 to HDI) or MDA (44 patients). The motor vehicle, electronics and paint industries, and painting and construction work, were among the most significant occupational fields. An in-house polymeric MDI (PMDI) test substance was superior to commercial MDI preparations. About half of the occupational cases related to MDI products were diagnosed by testing MDA. The most prominent cause of IPDI allergy comprised polyurethane paint hardeners. Some of the IPDI reactions could be explained by cross-allergy to isophoronediamine in epoxy products. Specific exposure to MDA was difficult to trace. CONCLUSIONS: MDA and PMDI test substances were significant in the diagnosis of MDI contact allergy.

Contact sensitization to methylisothiazolinone in Finland--a multicentre study.

BACKGROUND: Antimicrobials constitute the second most common cause of contact allergy to cosmetics. Methylisothiazolinone (MI), previously always used together with methylchloroisothiazolinone (MCI), has recently been approved in the EU for use on its own in cosmetics and also various industrial products. MCI has been classified as an extreme-strong and MI as a strong-moderate sensitizer. OBJECTIVES: To study the frequency of positive patch test reactions to MI, and its relevance and relation to MCI/MI sensitivity, in Finland. METHODS: Over a period of 3 years (2006-2008), MI 0.1% (1000 ppm) and 0.03% (300 ppm) were patch tested in 10,821 patients at eight Finnish dermatological clinics. During 2008, patients with positive reactions to MI were asked to take part in a repeated open application test (ROAT). RESULTS: Of the patients tested, 1.4% and 0.6% showed positive patch test reactions to 0.1% and 0.03% MI, respectively. Sixty-six per cent of those who were MI-positive were also positive to 100 ppm MCI/MI. Thirty-three agreed to undergo the use test, and 10 of these gave positive results (30%). CONCLUSIONS: Our data show that MI used alone also potentially induces contact allergy. Careful monitoring is needed to determine whether or not this antimicrobial is safe to use in cosmetics.

Contact allergy to aliphatic polyisocyanates based on hexamethylene-1,6-diisocyanate (HDI).

BACKGROUND: Aliphatic polyisocyanates based on hexamethylene 1,6-diisocyanate (HDI) are components of lacquers, coatings, and spray paints. They are mainly composed of HDI trimers, but also contain larger oligomers, and minute amounts of HDI monomers (<1%). HDI trimers occur as biuret, isocyanurate and asymmetrical types. OBJECTIVES: We report on 4 patients with allergic contact dermatitis/contact allergy resulting from HDI-based polyisocyanates in polyurethane paints. METHODS: The patients were examined at the Finnish Institute of Occupational Health in 2000-2009. The first two patients were diagnosed by testing with their own polyurethane hardeners and ingredients of the hardeners. In 2002, HDI isocyanurate (HDI-IC) trimer was added to our isocyanate series, and the last two patients were screened with the series. RESULTS: Patient no. 1 was exposed and sensitized to HDI biuret trimer, patient no. 2 to HDI-IC trimer, and patient no. 4 to HDI asymmetrical trimer. Patient no. 3 was positive with HDI-IC trimer. He had been handling several paint hardeners containing HDI-based polyisocyanates, but the subtypes of the trimers remained unidentified. All 4 patients were negative with HDI monomer. CONCLUSIONS: HDI trimers are novel contact allergens in workers who handle polyurethane paints. The allergic reactions cannot be explained by sensitization to HDI monomer.

Occupational methacrylate and acrylate allergy--cross-reactions and possible screening allergens.

BACKGROUND: Acrylic resin monomers, especially acrylates and methacrylates, are important occupational allergens. AIMS: To analyse patterns of concomitant patch test reactions to acrylic monomers in relation to exposure, and to suggest possible screening allergens. PATIENTS/METHODS: We reviewed the patch test files for the years 1994-2009 at the Finnish Institute of Occupational Health for allergic reactions to acrylic monomers, and analysed the clinical records of sensitized patients. RESULTS: In a group of 66 patients allergic to an acrylic monomer, the most commonly positive allergens were three methacrylates, namely ethyleneglycol dimethacrylate (EGDMA), 2-hydroxyethyl methacrylate (2-HEMA) and 2-hydroxypropyl methacrylate (2-HPMA), and an acrylate, namely diethyleneglycol diacrylate (DEGDA). The patterns of concomitant reactions imply that exposure to methacrylates may induce cross-reactivity to acrylates, whereas exposure to acrylates usually does not lead to cross-allergy to methacrylates. Screening for triethyleneglycol diacrylate (TREGDA) in the baseline series was found to be useful, as 3 of 8 patients with diagnosed occupational acrylate allergy might have been missed without the screening. CONCLUSIONS: A short screening series of four allergens, EGDMA, DEGDA, 2-HPMA and pentaerythritol triacrylate (PETA), would have screened 93% of our 66 patients; each of the remaining 5 patients reacted to different acrylic monomer(s).

A 6-month follow-up study of 1048 patients diagnosed with an occupational skin disease.

BACKGROUND: Occupational skin diseases (OSDs) often have considerable medical and occupational consequences. Previous data on prognostic factors have been derived from studies with fairly small sample sizes. OBJECTIVES: To determine the medical and occupational outcome in 1048 patients diagnosed with OSD at the Finnish Institute of Occupational Health and to identify the prognostic risk factors for the continuation of OSD. METHODS: Patients examined in 1994-2001 filled out a follow-up questionnaire 6 months after the diagnosis. Data on atopy, contact allergies, and occupation were analysed. RESULTS: Six months after the diagnosis the skin disease had healed in 27% of the patients. The OSD had cleared up in 17% of those with no changes at work, and in 34% of those who had changed their job/occupation. The best clearing had occurred in the patients with contact urticaria (35%), whereas the healing of allergic (27%) and irritant (23%) contact dermatitis was similar. The risk factors for continuing occupational contact dermatitis (OCD) were no changes in work, age > 45 years, food-related occupations, respiratory atopy, and male sex. CONCLUSIONS: The healing of OSD was associated with discontinuation of the causative exposure. A change in work and the presence of easily avoidable work-related allergies were associated with a good prognosis.

Contact allergy to epoxy (meth)acrylates.

BACKGROUND: Contact allergy to epoxy (meth)acrylates, 2,2-bis[4-(2-hydroxy-3-methacryloxypropoxy) phenyl]propane (bis-GMA), 2,2-bis[4-(2-hydroxy-3-acryloxypropoxy)phenyl]-propane (bis-GA), 2,2-bis[4-(methacryl-oxyethoxy)phenyl] propane (bis-EMA), 2,2-bis[4-(methacryloxy)phenyl]-propane (bis-MA), and glycidyl methacrylate (GMA) is often manifested together with contact allergy to diglycidyl ether of bisphenol A (DGEBA) epoxy resin. OBJECTIVE: To analyse patterns of concomitant allergic reactions to the five epoxy (meth)acrylates in relation to exposure. METHODS: We reviewed the 1994-2008 patch test files at the Finnish Institute of Occupational Health (FIOH) for reactions to the five epoxy (meth)acrylates, and examined the patients' medical records for exposure. RESULTS: Twenty-four patients had an allergic reaction to at least one of the studied epoxy (meth)acrylates, but specific exposure was found only in five patients: two bis-GMA allergies from dental products, two bis-GA allergies from UV-curable printing inks, and one bis-GA allergy from an anaerobic glue. Only 25% of the patients were negative to DGEBA epoxy resin. CONCLUSIONS: The great majority of allergic patch test reactions to bis-GMA, bis-GA, GMA and bis-EMA were not associated with specific exposure, and cross-allergy to DGEBA epoxy resin remained a probable explanation. However, independent reactions to bis-GA indicated specific exposure. Anaerobic sealants may induce sensitization not only to aliphatic (meth)acrylates but also to aromatic bis-GA.

The European baseline series in 10 European Countries, 2005/2006--results of the European Surveillance System on Contact Allergies (ESSCA).

BACKGROUND: Continual surveillance based on patch test results has proved useful for the identification of contact allergy. OBJECTIVES: To provide a current view on the spectrum of contact allergy to important sensitizers across Europe. PATIENTS/METHODS: Clinical and patch test data of 19 793 patients patch tested in 2005/2006 in the 31 participating departments from 10 European countries (the European Surveillance System on Contact Allergies' (ESSCA) www.essca-dc.org) were descriptively analysed, aggregated to four European regions. RESULTS: Nickel sulfate remains the most common allergen with standardized prevalences ranging from 19.7% (central Europe) to 24.4% (southern Europe). While a number of allergens shows limited variation across the four regions, such as Myroxylon pereirae (5.3-6.8%), cobalt chloride (6.2-8.8%) or thiuram mix (1.7-2.4%), the differences observed with other allergens may hint on underlying differences in exposures, for example: dichromate 2.4% in the UK (west) versus 4.5-5.9% in the remaining EU regions, methylchloroisothiazolinone/methylisothiazolinone 4.1% in the South versus 2.1-2.7% in the remaining regions. CONCLUSIONS: Notwithstanding residual methodological variation (affecting at least some 'difficult' allergens) tackled by ongoing efforts for standardization, a comparative analysis as presented provides (i) a broad overview on contact allergy frequencies and (ii) interesting starting points for further, in-depth investigation.

Occupational allergic contact dermatitis from cinnamon including one case from airborne exposure.

BACKGROUND: The bark of the cinnamon tree is used as a spice; its flavour is from an essential oil containing mainly cinnamal. OBJECTIVE: To report new cases of occupational allergic contact dermatitis (ACD) from cinnamon and a novel case of airborne cinnamon contact allergy. METHODS: We examined the patient material of two dermatological clinics in Helsinki to find cinnamon contact allergic patients and review their clinical records. RESULTS: We found six patients with delayed contact allergy to cinnamon. In four patients, cinnamon was the main cause of occupational ACD. Three of them had dermatitis on their hands and one patient on the face and neck. In the latter case, the exposure was shown to be airborne. In addition, the fifth patient was occupationally sensitized to cinnamon, but it was not the main cause of his hand dermatitis. In the sixth patient, cinnamon allergy was considered to derive from cross-allergy to fragrances. Five of the patients reacted to cinnamal separately and in fragrance mix I. None of the six patients had immediate-type cinnamon allergy. CONCLUSIONS: Occupational contact allergy to cinnamon is rare but needs to be considered in workers handling foods. Cinnamal is possibly the main allergen in cinnamon.

Respiratory symptoms and conditions related to occupational exposures in machine shops.

OBJECTIVES: Since there are few data on the effects of metalworking in populations representing a variety of metal companies or on dose-response relationships concerning metalworking, this study investigated the relationship between occupational exposures in machine shops and the occurrence of upper and lower respiratory symptoms, asthma, and chronic bronchitis. METHODS: A cross-sectional study of 726 male machine workers and 84 male office workers from 64 companies was conducted in southern Finland. All of the participants filled out a questionnaire, and aerosol measurements were performed in 57 companies. RESULTS: Exposure to metalworking fluids (MWF) showed a greater risk [odds ratio (OR)>or=2) for upper-airway symptoms, cough, breathlessness, and current asthma than exposures in office work did. Exposure to aerosol levels above the median (>or=0.17 mg/m3 in the general workshop air) was related to an increased risk (OR>or=2) of nasal and throat symptoms, cough, wheezing, breathlessness, chronic bronchitis, and current asthma. Machine workers with a job history of >or=15 years experienced increased throat symptoms, cough, and chronic bronchitis. CONCLUSIONS: This large study representing machine shops in southern Finland showed that machine workers experience increased nasal and throat symptoms, cough, wheezing, breathlessness, and asthma even in environments with exposure levels below the current occupational exposure limit for oil mists. The study suggests that improving machine shop environments could benefit the health of this workforce. It also suggests that it is time to consider reducing the current Finnish occupational exposure limit for oil mist or introducing the use of other health-relevant indicators of exposure.

Analysis of allergens in metalworking fluids.

BACKGROUND: Metalworking fluids (MWFs) are well-known causes of occupational contact dermatitis in machinists. OBJECTIVE: To gain information about skin sensitizers in MWFs and to compare it with the information in safety data sheets (SDSs). METHODS: A total of 17 samples of MWF concentrates were analysed for skin sensitizers known or suspected to be used in MWF. Alkanolamines, formaldehyde, isothiazolinones, methyldibromo glutaronitrile (MDBGN), and iodopropynyl butylcarbamate (IPBC) were separated by liquid chromatography. Resin acids of colophonium (colophony) were separated by gas chromatography. The substances were identified with mass spectrometric detection and ultraviolet detection. RESULTS: Of the MWFs, 15 contained 6-39% of alkanolamines, mostly monoethanolamine and triethanolamine. Formaldehyde was detected in all MWFs: the concentrations of total formaldehyde ranged between 0.002% and 1.3%. Benzisothiazolinone and octylisothiazolinone were detected in one fluid each. IPBC was detected in nine MWFs, and the highest concentration was 0.09%. Methylisothiazolinone and MDBGN were not detected in any of the fluids. Resin acids of colophonium were detected in seven MWFs in concentrations ranging from 0.41% to 3.8%. On the whole, the allergens analysed were poorly declared in the SDSs. CONCLUSIONS: The content of total formaldehyde was not declared in any SDS. IPBC, a relatively new allergen, seems to be common in MWFs. Isothiazolinones may be relevant allergens of machinists, and they should be analysed in MWFs in case other sources are not identified. The occupational relevance of positive patch test results to MWF ingredients in machinists is difficult to determine if information in the SDSs is relied upon.

Occupational methacrylate and acrylate allergy from glues.

BACKGROUND: Glues and sealants are important causes of methacrylate and acrylate allergy. AIM: This study aimed to analyse patterns of allergic patch test reactions to acrylic monomers in relation to exposure in patients sensitized from glues. PATIENTS/METHODS: We screened the patch test files at the Finnish Institute of Occupational Health from 1994 to 2006 for allergic reactions in the 'Methacrylate series' and analysed the clinical records of sensitized patients. Only patients who had handled acrylic glues at work were included. RESULTS: 10 patients had allergic reactions to acrylic monomers and had been sensitized from glues at work. 9 of them had used anaerobic sealants, 3 cyanoacrylate-based instant adhesives, and 1 patient a bi-component instant adhesive. All the patients reacted to 2-hydroxyethyl methacrylate (2-HEMA) and ethyleneglycol dimethacrylate (EGDMA); reactions to 2-hydroxypropyl methacrylate, triethyleneglycol dimethacrylate, and tetrahydrofurfuryl methacrylate were also common. The first 4 methacrylates were found in the glues used by the patients. Ethyl cyanoacrylate (ECA) gave no reactions, but 1 patient reacted weakly to her own ECA-based glue. CONCLUSION: 2-HEMA and EGDMA are good screeners for contact allergy to anaerobic sealants and also detected a single case deriving from bi-component acrylic glue.

Contact allergy to 2,5-dimercapto-1,3,4-thiadiazole and phenyl-alpha-naphtylamine, allergens in industrial greases and lubricant oils--contact allergy to water-insoluble greases is uncommon but needs to be considered in some workers.

BACKGROUND: Industrial lubricants are usually made of petroleum and contain no water. Industrial greases and neat oils (insoluble metalworking oils) cause contact allergy relatively seldom, and reported allergies to the components of engine oils, such as hydraulic oils, are extremely scarce. OBJECTIVE: The aim was to describe patients with contact allergy to the components of industrial lubricants. RESULTS: We describe 2 patients with allergic reactions to 2,5-dimercapto-1,3,4-thiadiazole. Their allergies derived from guide-way oil and grease. Guide-way oils are lubricants for metalworking machines. Machinists may have continuous skin contact to these oils, as the oils are leaked to the circulating metalworking fluid system and form the so-called 'tramp oil'. We also report a new case with allergy to phenyl-alpha-naphtylamine in grease. CONCLUSION: 2,5-Dimercapto-1,3,4-thiadiazole is an aromatic compound used in oils and greases. It has previously caused contact allergy to workers who have handled the pure chemical, but to our knowledge, there are no previous reports of contact allergy from products containing the chemical in a relatively low concentration. 1 of our 2 cases had been sensitized from grease and the other from a guide-way oil. The latter case shows that machinists may become sensitized to lubricants that leak to the metalworking fluid system.

1,2-benzisothiazolin-3-one in disposable polyvinyl chloride gloves for medical use.

BACKGROUND: Benzisothiazolinone is used as a slimicide in the manufacture of disposable powder-free polyvinyl chloride (PVC) gloves. We recently reported 6 patients from dentistry and health care probably sensitized to benzisothiazolinone in PVC gloves. OBJECTIVE: The study aimed to investigate how widely disposable PVC gloves for medical use on the Finnish market in 2006 contain benzisothiazolinone and to report new cases from 2 clinics in Helsinki. METHODS: 31 brands of disposable PVC gloves were analysed for their benzisothiazolinone content. We looked through the patient material of Helsinki University Central Hospital to find benzisothiazolinone allergic patients. We also described 3 previously unpublished benzisothiazolinone allergic patients from Finnish Institute of Occupational Health. RESULTS: 9 (30%) of the 31 glove brands contained 3-26 p.p.m. benzisothiazolinone. From the 2 clinics, we found 5 new benzisothiazolinone allergic patients who had used PVC gloves containing benzisothiazolinone. In addition, 3 patients had used disposable PVC gloves whose benzisothiazolinone content remained unknown. CONCLUSIONS: In Finland, benzisothiazolinone in powder-free PVC gloves has caused a small epidemic of allergic contact dermatitis in dental personnel and other health care workers. 1/3 of the disposable PVC gloves contained some benzisothiazolinone. A concentration of 20 p.p.m. benzisothiazolinone in a glove seems to be enough for sensitization.

Methacrylate and acrylate allergy in dental personnel.

BACKGROUND: Methacrylates are important allergens in dentistry. OBJECTIVE: The study aimed to analyse patch test reactivity to 36 acrylic monomers in dental personnel in relation to exposure. METHODS: We reviewed the test files at the Finnish Institute of Occupational Health from 1994 to 2006 for allergic reactions to acrylic monomers in dental personnel and analysed the clinical records of the sensitized patients. RESULTS: 32 patients had allergic reactions to acrylic monomers: 15 dental nurses, 9 dentists, and 8 dental technicians. The dentists and dental nurses were most commonly exposed to 2-hydroxyethyl methacrylate (2-HEMA), triethyleneglycol dimethacrylate (TREGDMA), and 2,2-bis[4-(2-hydroxy-3-methacryloxypropoxy) phenyl]propane (bis-GMA). 8 dentists and 12 dental nurses were allergic to 2-HEMA. The remaining dentist was positive to bis-GMA and other epoxy acrylates. The remaining 3 dental nurses reacted to diethyleneglycol diacrylate (DEGDA) or triethyleneglycol diacrylate (TREGDA), but not to monofunctional and multifunctional methacrylates. Our dental technicians were mainly exposed and sensitized to methyl methacrylate (MMA) and ethyleneglycol dimethacrylate (EGDMA). 1 technician reacted only to 2-HEMA, and another to ethyl methacrylate (EMA) and ethyl acrylate (EA). CONCLUSIONS: 2-HEMA was the most important allergen in dentists and dental nurses, and MMA and EGDMA in dental technicians. Reactions to bis-GMA, DEGDA, TREGDA, EMA and EA were relevant in some patients.