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Background: The textile dye mix (TDM) 6.6% in petrolatum contains Disperse Blue (DB) 35, Disperse Yellow 3, Disperse Orange (DO) 1 and 3, Disperse Red 1 and 17, and DB 106 and 124. The most frequent allergen in TDM-positive patients is DO 3. Around 85% of para-phenylenediamine (PPD)-allergic dermatitis patients have been positive to DO 3. There has been a discussion to exclude DO 3 from TDM 6.6% because of strong simultaneous reactions to TDM and PPD. Objectives: To study if DO 3 can be excluded from TDM 6.6%. Methods: Patch tests were performed on 1481 dermatitis patients with TDM 6.6%, TDM 7.0% (without DO 3 but the other disperse dyes at 1.0% each), DO 3 1.0%, and PPD 1.0% pet. Results: Contact allergy to TDM 6.6% was 3.6% and to TDM 7.0% was 3.0%. All 26 DO 3-positive patients were positive to PPD. The 44 patients positive to TDM 7.0% plus the 13 positive to PPD and TDM 6.6% but negative to TDM 7.0% were 57, outnumbering the 53 positive to TDM 6.6%. Conclusion: TDM 7.0% can replace TDM 6.6% in the Swedish baseline series, since TDM 7.0% together with PPD 1.0% will detect patients with textile dye allergy.

Disperse dyes (DDs) are the most prevalent causes of textile-related allergic contact dermatitis and are used for colouring synthetic textile materials based on fibres such as polyester, acrylic, acetate and polyamide. Eight DDs are included in a textile dye mix (TDM) 6.6% petrolatum (pet.) in the European baseline patch test series.The aim of this study was to patch test TDM 6.6% pet. positive individuals with the extracts of synthetic fibre clothes that do not contain any of the pure DDs present in the TDM 6.6% to study the reactivity pattern.Seventy-three TDM-positive former patients tested between 2012 and 2017 at the Department of Occupational and Environmental Dermatology in Malmö, Sweden were invited to join the study, 10 participated. Twenty-four textile items (collected in nine countries in Europe, Asia and North America in 2012) were extracted in dichloromethane. The TDM 6.6% was patch tested simultaneously with the 24 textile item preparations in petrolatum made from the extracts. Prior to patch testing the participants filled the 7-question questionnaire regarding possible symptoms from textile exposure.Ten individuals, agreed to join the study. Eight of them reacted to TDM 6.6%. Nine participants reacted to 20 of 24 extracts. One reacted to 19 extracts, another to 14, 3 to 5 extracts, 1 to 4, 1 to 3 extracts and 2 to 2 extracts. One was negative to all tested preparations including TDM 6.6%. The participants mainly reacted to six textile extracts. All controls tested negatively to tested extracts. Four individuals of the 10 TDM-allergic individuals previously had had problems after wearing clothes. Four out of the 10 participants had had atopic eczema in childhood. All women had dyed their hair with permanent hair dyes but none of the males.TDM-positive patients react to textile extracts made from synthetic garments, even if they do not contain any of the pure DDs present in TDM 6.6%. More studies are needed to pin-point the culprit haptens in these extracts.

BACKGROUND: Contact allergy to fragrance mix I (FM I) is over-represented in patients photoallergic to ketoprofen. The prevalence of contact allergy to two components of FM I, cinnamal and cinnamyl alcohol, in ketoprofen-photoallergic patients is higher than in dermatitis patients.OBJECTIVE: To explore the prevalence of contact allergy to FM I and its individual components in patients with photocontact allergy to ketoprofen, and to compare with a dermatitis and the general population.METHODS: Data on patch and photopatch tests performed between 2009-2018 were collected. Ketoprofen-photoallergic patients were compared with dermatitis patients and published data on the general population regarding the prevalence and the distribution of contact allergy to FM I and its components.RESULTS: A higher prevalence of contact allergy to cinnamyl alcohol compared to cinnamal (23.3% vs 10.0%), and eugenol compared to isoeugenol (23.3% vs 6.7%), was observed in ketoprofen-photoallergic patients, while the relationship was the opposite in dermatitis group (0.7% vs 1.05%; 0.4% vs 0.9%). Overall prevalence of contact allergy to several components of FM I was significantly higher in ketoprofen-photoallergic patients.CONCLUSIONS: Contact allergy to FM I and many of its components is over-represented in patients photoallergic to ketoprofen compared to dermatitis patients and the general population. This article is protected by copyright. All rights reserved. (Less)

Recently, aluminum chloride hexahydrate (ACH) 10.0% petrolatum (pet) was recommended for patch testing to detect aluminum contact allergy. Aluminum lactate (AL) may be as reliable a test substance as ACH.We aimed to investigate the frequencies of aluminum allergy when ACH and AL were used in patch testing consecutive patients.Petrolatum preparations of ACH 10.0% and AL 12.0% were added to the baseline series in 2010-2017. Aluminum chloride hexahydrate 10.0% pet was added to the children baseline series from July 1, 2012, to December 31, 2017.A total of 5448 patients were patch tested with the extended baseline series and 196 children with the extended children baseline series. Forty-eight of the 5448 adults (0.9%) and 10 of the 196 children (5.1%) were diagnosed with aluminum contact allergy. A significant difference was found between the aluminum allergy frequencies in children and adults patch tested with ACH in 2013-2017 (P0.001). The difference between the frequencies of contact allergies for the 2 aluminum salts is not statistically significant.Patch testing with ACH and AL demonstrated similar contact allergy frequencies. To detect aluminum allergy, patch testing with ACH 10.0% pet is recommended. Aluminum chloride hexahydrate 10.0% pet should be considered for inclusion in baseline series for patch testing adults and children.

Background: Non-occupational cases of contact dermatitis to finished wood are occasionally reported from contact with wooden jewellery, musical instruments, knife handles and wooden footwear. Two female patients, 26 and 34 years old, developed acute eczema on the wrists after they worn in the summer a kind of catholic bracelet called “memorabilia” made by single wooden chunks with over-impressed iconic religious images. Objectives: To identify the culprit photoallergen responsible for the reported adverse reactions suspected to be a compound of the wooden bracelets. Methods: Three months after the resolution of the dermatitis, patch test and photo-patch tests were performed with the S.I.D.A.P.A. (Italian Society of Allergic, Occupational and Environmental Dermatology) standard series, and with wood sawdust obtained from both bracelets and tested at 5% in pet. A thin-layer chromatogram (TLC) strip and an extract made from the bracelets were tested in both the patients as patch test and photo-patch test. The extracts of the wooden bracelets were analyzed by gas chromatography – mass spectrometry (GC-MS). Results: Patch tests and photo-patch test with standard series turned out negative. Photo-patch tests with wood sawdust in pet. 5% evidenced a positive reaction (++) in both patients. Two chemicals were detected in the wooden bracelets with GC-MS: dibutylphthalate, commonly used as plasticizer, and 8,8-dimethyl-2H,8H-benzo[1,2-b:3,4-b']dipyran-2-one, a coumarin. Patch test with TLC did not elicit positive reactions but the photo-patch test with TLC gave positive reactions in both the patients to the same invisible spot on the strips. Two coumarins (8,8-dimethyl-2H,8H-benzo[1,2-b:3,4-b']dipyran-2-one and 8,8-dimethyl-2H,8H-benzo[1,2-b:5,4-b']dipyran-2-one) were detected in the spot with GC-MS. Conclusion: Coumarins are chemicals found in many plants with a known photo-allergic potential. They are probably the main photo-allergens in religious wooden bracelets instead of quinones and psoralens hypothesized in previous reports.

Background: The textile dye mix (TDM) 6.6% pet. contains Disperse Blue (DB) 35, Disperse Yellow 3, Disperse Orange (DO) 1 and 3, Disperse Red 1 and 17, and DB 106 and 124. The most frequent allergen in TDM-positive patients is DO 3. Around 85% of p-phenylenediamine (PPD)-allergic dermatitis patients have shown positive patch test reactions to DO 3. There has been a discussion to exclude DO 3 from TDM 6.6% because of frequent, strong reactions to TDM 6.6% and PPD. Objectives: To study if DO 3 can be omitted from a TDM. Methods: Patch tests were performed on 2250 dermatitis patients with TDM 6.6%, TDM 5.6% pet., TDM 7.0% pet., and PPD 1.0% pet.; 122 patients were also patch tested with DO 3 1.0% pet. Results: Among the 2250 patients patch tested, contact allergy prevalence to TDM 6.6% was 2.4%, to TDM 5.6% 1.8%, and to TDM 7.0% 2.0%. Of the 54 TDM 6.6%-positive patients, 55.6% reacted to PPD; as much as 42.2% of PPD-allergic women and 50% of PPD-allergic men reacted to TDM 6.6%. Of the 17 DO 3-positive patients, 94.1% showed a positive reaction to PPD. Conclusion: Results indicate that DO 3 can probably be omitted from TDM, but patch testing with TDM 6.6%, TDM 7.0%, DO 3 1.0%, and PPD 1.0% simultaneously is needed to finally decide whether it is possible or not. (Less)

SummaryBackground Contact allergy to aluminium has been reported more frequently in recent years. It has been pointed out that positive patch test reactions to aluminium may not be reproducible on retesting. Objectives To investigate possible variations in patch test reactivity to aluminium over time. Methods Twenty-one adults, who had previously reacted positively to aluminium, were patch tested with equimolar dilution series in pet. of aluminium chloride hexahydrate and aluminium lactate, four times over a period of 8 months. Results Thirty-six of 84 (43%) serial dilution tests with aluminium chloride hexahydrate and 49 of 84 (58%) serial dilution tests with aluminium lactate gave negative results. The range of reactivity varied between a negative reaction to aluminium chloride hexahydrate at 10% and/or to aluminium lactate at 12%, and a positive reaction to aluminium chloride hexahydrate at 0.1% and/or to aluminium lactate at 0.12%. The highest individual difference in test reactivity noticed was 320-fold when the two most divergent minimal eliciting concentrations were compared. Conclusions The patch test reactivity to aluminium varies over time. Aluminium-allergic individuals may have false-negative reactions. Therefore, retesting with aluminium should be considered when there is a strong suspicion of aluminium contact allergy.

SummaryBackground Fragrance mix I (FM I) and fragrance mix II (FM II) are included in the European baseline series as screening substances for fragrance contact allergy. Objectives To investigate the frequency of allergic reactions to FM I, FM II and their ingredients in consecutively patch tested patients. Materials and methods A retrospective analysis of data from 4430 patients patch tested between 2009 and 2015 was performed. Results Of the patients, 6.5% were FM I-positive and 3.2% were FM II-positive. Forty-five per cent of FM I-positive patients did not have positive reactions to FM I ingredients. Thirty-five per cent of those who were FM II-positive did not have positive reactions to FM II ingredients. Twenty-seven per cent of those with positive reactions to one or more of the FM I ingredients were FM I-negative, and 36% of those who had positive reactions to one or more of the FM II ingredients were FM II-negative. The allergens with the highest pick-up rates were Evernia prunastri (1.8%), cinnamal (1.3%), citral (1.2%), and hydroxyisohexyl 3-cyclohexene carboxaldehyde (1.2%). Significant differences were observed in the proportions of positive reactions to FM I, FM II, eugenol, isoeugenol, and farnesol when results from patch testing with materials from different suppliers were compared. Conclusions There is a risk of missing fragrance contact allergy when testing with only the fragrance mixes is performed. The use of preparations from different suppliers may affect the patch test results.

Background: Most patients with contact allergy to Asteraceae plants are patch test positive to sesquiterpene lactone mix (SLM). There are several reports among these patients of a flare-up of hand eczema after ingestion of food and beverages originating from Asteraceae plants. Aim: To investigate whether German chamomile tea can elicit systemic allergic dermatitis. Patients and Methods: Individuals with or without contact allergy to SLM were patch tested with an extract of German chamomile tea. Six weeks later, they were provoked with capsules containing either freeze-dried German chamomile tea or placebo capsules containing lactose, in a double-blind, randomized study. A numerical rating scale (NRS) was used to ascertain the volunteers' opinion of their hand eczema status. The study individuals were examined to detect a possible flare-up of healed patch test reactions to chamomile. Results: None of the subjects had a flare-up of healed patch test reactions. According to the NRS, SLM-positive individuals experienced a significant worsening of hand eczema, independently of whether they received chamomile or lactose capsules. Conclusion: No evidence suggestive of systemic allergic dermatitis was found. (Less)

Background: Allergic contact dermatitis (ACD) caused by hexavalent chromium, Cr(VI), is often severe and difficult to treat. The most common source of exposure to Cr(VI) in Sweden used to be cement, and more recently leather. The contact allergy can be diminished or inhibited if the exposure is decreased or ceases. Barrier creams against different kinds of allergens have been investigated for their protective properties which may offer protection against Cr(VI) exposure. Objectives: To investigate the capacity of formulas containing glutathione (GSH) and iron sulfate to inhibit elicitation of ACD in Cr(VI)-allergic individuals when exposed to Cr(VI). Methods: In 18 Cr(VI)-allergic volunteers the back was divided into eight patch test areas which were treated with preparations of possible barrier creams, prior to patch testing with a dilution series of potassium dichromate and a buffered extract of cement. Results: A significant reduction in reactivity to Cr(VI) and cement extract on skin treated with formulas containing GSH or iron sulfate was noticed, compared with untreated skin. Conclusion: Formulas containing GSH or iron sulfate in barrier creams inhibit ACD in individuals allergic to Cr(VI) when applied before exposure to Cr(VI) and cement extract. (Less)

Background: Allergic contact dermatitis caused by Cr(VI) is often severe and difficult to treat. Therefore, primary prevention is a main goal but secondary prevention can be valuable to ease the symptoms or prevent relapse of Cr(VI) dermatitis when sensitization has occurred. Barrier creams have been tried for many chemical substances, but until now there is no successful barrier cream against Cr(VI). Objectives: To investigate the ability of reducing agents to transform Cr(VI) into Cr(III) in an experimental situation, in order to find suitable chemicals to investigate for possible use in a barrier cream. Methods: The capacity to reduce the amount of Cr(VI) was analyzed in water solutions of acetylcysteine, cysteine, dihydroxyacetone, glutathione, and iron sulfate heptahydrate. Thereafter the reducing capacity of acetylcysteine, dihydroxyacetone, glutathione, and iron sulfate on the amount of Cr(VI) in cement extracts was investigated. The content of Cr(VI) in the test solutions and in the cement extracts was estimated by the diphenyl carbazide spot test. Results: All of the chosen chemicals reduced the amount of Cr(VI) in the test solutions and in the cement extracts to some extent. The reducing capacity was most prominent for iron sulfate. Conclusion: A reducing capacity was found for all chosen chemicals. (Less)

BACKGROUND: There is an ongoing discussion on whether routinely patch testing with p-phenylenediamine (PPD) 1.0% pet. is safe, owing to the risk of patch test sensitization. Late-appearing patch test reactions may reflect patch test sensitization, but may also be attributable to a low degree of pre-existing sensitization.OBJECTIVES: To follow the positive patch test reactions to PPD and its salt PPD dihydrochloride (PPD-DHC) in order to characterize reaction patterns concerning time and dose in PPD-sensitized individuals.METHODS: Volunteers with previous reactions to PPD 1.0% were included and patch tested with PPD and PPD-DHC in equimolar dilution series. There were then seven follow-up visits over a period of 28 days.RESULTS: Twenty-six volunteers completed the study, of whom 23 of 26 (88%) reacted to PPD 1.0%, and 69% reacted to PPD 0.32%. Altogether, 42% and 27% reacted to the corresponding equimolar concentrations of PPD-DHC. After day 7, no new reactions were observed to any concentration tested, either of PPD or of PPD-DHC.CONCLUSION: No late-appearing reactions to PPD or PPD-DHC were observed at any dose. There is a risk of missing contact allergy when the dose is decreased.

Background: Five workers from a plant manufacturing concrete wall panels and beams were referred to our department because of suspected occupational dermatitis. When patch tested, 3 workers reacted to potassium dichromate. Four workers reacted to ethylenediamine dihydrochloride, without any obvious exposure. Owing to the high proportion of workers with recent-onset skin disease, an investigation of all workers at the plant was initiated. Objectives: To investigate the prevalence of occupational dermatitis and contact allergy in the workers at the plant. Methods: All 24 workers at the plant underwent a clinical investigation and were patch tested. Results: Four cases of allergic occupational contact dermatitis and 3 cases of irritant occupational contact dermatitis were diagnosed. Contact allergy to potassium dichromate was found in 4 workers. All 4 also reacted to ethylenediamine dihydrochloride and/or amines that were present as additives in the cement. Conclusions: Chromate contact allergy can still be found in concrete workers, despite the legislation regulating the amount of hexavalent chromium (chromate) in cement. Occupational contact allergy to amines can be found in workers exposed to cement and concrete, so amines should be tested in these workers.

Background: Solvent Orange (SO) 60 is a perinone-type dye that is often used in plastic materials such as spectacle frames and has been shown to cause contact allergy. The first case of SO 60 allergic contact dermatitis caused by spectacle frames was reported in 1999, and the second in 2011. We have recently seen 10 patients, of whom 6 developed dermatitis in the retroauricular/temporal area after wearing plastic spectacles. Objectives: To report the cause of the dermatitis in the 10 patients and to describe our first case with occupational SO 60 contact allergy. Methods: In this retrospective study, patch test results of 10 patients, tested with the Swedish baseline series and our specific spectacle and/or plastic series, including SO 60 1.0% pet., in 2011-2017 were analysed. Results: Ten patients, 2 males and 8 females, aged 43 to 71 years, reacted positively to SO 60 1.0% pet., namely, 4 pensioners, 2 nurses, 1 office worker, 1 teacher, 1 shop assistant, and 1 unemployed person. Four of the patients had an atopic history. Patch test reactions varied from + to +++; some had spread >20 cm outside the test area in terms of erythematous, infiltrated skin with papules. Retesting of patient no. 1 with serial dilutions of SO 60 in acetone showed positive reactions down to 1 ppm. Three patients reacted to the extracts of their earpieces. Gas chromatography-mass spectrometry was used to confirm the presence of SO 60 in 2 earpieces. Conclusions: SO 60 should be included in any spectacle patch test series that may be used. If there is a strong suspicion of contact allergy to SO 60 before patch testing, lowering the test concentration from 1.0% to 0.01% should be considered. (Less)

The results from a previous study indicated the presence of several possible sensitizers formed during oxidation of the potent sensitizer p-phenylenediamine (PPD) to which PPD-sensitized patients might react, in various patterns.

Background: In a population study using TRUE Test®, we noted late reactions to p-tert-butylphenol-formaldehyde resin (PTBP-FR) in 0.5% of subjects tested.Objectives: In order to explore possible te ...

Keywords: 2(3H)-benzothiazolone; 7-oxodehydroabietic acid methyl ester; colophonium; contact dermatitis; gas chromatography–mass spectrometry (GCMS); methyl dehydroabietate; patch testing; shoes; thin-layer chromatography (TLC)

Background: Historically, allergic contact dermatitis caused by hexavalent chromium [Cr(VI)] in cement was the most common cause of invalidity attributable to skin disease in Sweden. Since the legislation to reduce Cr(VI) in cement was introduced in 1989, we rarely see allergic contact dermatitis caused by cement. Objectives: To examine the frequency of contact allergy to Cr(VI) in southern Sweden in 2005-2014. Methods: We investigated the occurrence of positive reactions to potassium dichromate 0.5% pet. in consecutively tested dermatitis patients, and compared the occurrence of atopic dermatitis, localization of dermatitis and simultaneous positive reactions to cobalt chloride and nickel sulfate in the Cr(VI)-positive patients with those in a group of patients with a similar age and sex distribution. Results: In total, 6482 patients were tested, and 233 Cr(VI)-allergic individuals were found (3.6%). A significantly higher proportion of atopic dermatitis was found among Cr(VI)-allergic patients, and a significantly higher share of foot dermatitis was found among Cr(VI)-allergic women, than among controls. Cr(VI) allergy was less likely when both nickel allergy and cobalt allergy were present. Conclusion: A relatively high frequency of contact allergy to Cr(VI) was found. The cause has shifted from cement exposure to other exposures, probably mainly leather. (Less)

The use of permanent hair dyes exposes hairdressers to contact allergens such as p-phenylenediamine (PPD), and the preventive measures are insufficient.

Several of the ingredients in fragrance mix I (FM I) have been shown to evaporate from petrolatum preparations applied in test chambers to an extent that can be suspected to affect the patch test result.

Oak moss absolute (Evernia prunastri extract) contains a large number of substances, among them the potent allergens atranol and chloroatranol. Since 2008, their content in oak moss absolute has been restricted by the International Fragrance Association to a maximum level of 100 ppm each.

Trifluoroacetic acid is a very strong carboxylic acid. The acid has been suspected to have similar toxic effects as hydrofluoric acid on skin contact. Hydrofluoric acid is highly toxic, owing to skin penetration by fluoride ions. A spill of hydrofluoric acid on the skin may be fatal. As trifluoroacetic acid contains fluorine, patients with chemical burns caused by trifluoroacetic acid have been given particular attention when treated in the hospital.

Simultaneous contact allergies to Disperse Orange 1, 4-nitroaniline and p-aminodiphenylamine (PADPA), as well as to other disperse azo dyes and to p-phenylenediamine (PPD), have been reported. Cross-reactivity is one of the possible explanations for simultaneous reactions between PPD and disperse azo dyes. Some metabolites from the azo reduction of these disperse azo dyes could be sensitizers, as human skin bacteria produce azo reductases.

Several disperse dyes (DDs) are still considered to be the most important allergens in textile dermatitis, but there are sparse data about their current use in textiles. The aim of this review was to evaluate published studies and reports on contact allergy to DDs published in PubMed during the last 22 years (1990-2012). Prevalence data are provided by study and by dye, as well as by the described clinical peculiarities of DD dermatitis. We reviewed 54 studies. In total, 26 DDs were tested. The average prevalence in screening studies was >1% for Disperse Blue 106, Disperse Blue 124, and Disperse Orange 3. There is a lack of data on patch testing with Disperse Blue 26, Disperse Blue 102, Disperse Orange 37, Disperse Orange 149, Disperse Yellow 23 and Disperse Yellow 49, which are listed as allergens by the EU Commission. It is necessary to check the purity and identity of dyes used for patch testing, confirm the clinical relevance of positive reactions by patch testing with suspected textiles, and, if the results are positive, determine the culprit dye.

Background. A 43-year-old woman was referred by her occupational health service with suspected occupational contact dermatitis. In connection with the investigation, a workplace visit was undertaken at her company, which used an adhesive based on pre-polymeric diphenylmethane diisocyanate in one of its units. During the visit, we became aware of six other employees with skin problems who were then referred to our department for investigation. Objectives. To investigate the seven employees complaining about skin problems. Methods. Seven employees were patch tested with a baseline series, an isocyanate series, and a series with work material. Results. Five of seven patients had occupational contact allergy. Four reacted to isocyanate-related test preparations, and one to a cleanser used at the workplace. Conclusions. Workplace visits constitute an important part of an occupational investigation, as they might give a broader picture of the problems at a company. In this case, it was found that 5 of 100 employees currently had or had previously had occupation-related skin problems. Owing to 'healthy worker selection', some of these patients might have been missed if we had not performed a full-scale workplace visit. (Less)

Background: It is known that, in vitro, human skin bacteria are able to split disperse azo dyes into the corresponding aromatic amines, some of which are sensitizers in the local lymph node assay. We hypothesize that the molecules of disperse dyes migrate onto the skin while garments are worn, and are metabolized and degraded by commensal skin bacteria. These molecules penetrate the skin and induce sensitization. Objectives: To evaluate the elicitation capacities of the possible azo-degradation products of the selected azo disperse dyes in patients allergic to them and to compare it with the elicitation capacities of other para-compunds. Methods: Ten patients allergic to Disperse Yellow 3 (DY3) and/or Disperse Orange 1 (DO1) were patch tested with a dilution series of the purified dyes 4-nitroaniline and p-aminodiphenylamine in concentrations equimolar to those of purified DO1 in the dilution series, as well as 4-aminoacetanilide and 2-amino-p-cresol in concentrations equimolar to those of purified DY3 in the dilution series. Results: Three patterns of patch test reactions could be seen. The 6 patients who were positive to DO1 and DY3 also reacted to p-aminodiphenylamine and 2-amino-p-cresol. Two patients were positive to DO1 only, and both reacted to p-aminodiphenylamine, but to neither 4-aminoacetanilide or 2-amino-p-cresol. Two patients did not react to DO1 or DY3 on this occasion. Conclusion: We show that it is possible that the major sensitizers in contact allergy to DO1 and DY3 are their metabolites, p-aminodiphenylamine and 2-amino-p-cresol, respectively, which might be formed by the azoreductase pathway of skin bacteria.

Background: Although acrylate/methacrylate allergy has been frequently reported, until now patch testing with this group of allergens has been unwieldy, requiring the application of large supplementary series in most centres. Objectives: To formulate and evaluate two mixes of acrylate/methacrylate allergens in three centres (Malmo, Singapore, and Leuven). Patients/materials/methods: All patients tested with the baseline series during the study period were also patch tested with the mixes. Mix 1 consisted of: triethyleneglycol diacrylate (TREGDA) 0.1% wt/wt, 2-hydroxyethyl methacrylate (2-HEMA) 1.0% wt/wt and ethyleneglycol dimethacrylate 1.0% wt/wt in petrolatum. Mix 2 consisted of: TREGDA 0.1% wt/wt and 2-HEMA 2.0% wt/wt in pet. The separate components of the two mixes were also tested simultaneously. Results. There were 25 (5 males; 20 females) positive reactions to mix 1 with 16 in Malmo, 8 in Singapore, and 1 in Leuven. Positive reactions to mix 2 were seen only in Malmo, in 8 female patients. Thus, the positive reaction rate for mix 1 was 8.3% overall (Malmo 7.7%, Singapore 18.6%, and Leuven 2.1%), and that for mix 2 was 2.7% overall (Malmo 3.8%, Singapore 0%, and Leuven 0%). Of the 16 positive reactions to mix 1 in Malmo, only 4 were considered to be true allergic reactions, as the component allergen testing gave totally negative results in 12/16. For mix 2, only 3/8 positive reactions were considered to be true allergic reactions, as the component testing was negative in 5/8. Many doubtful (10-20%) and positive but non-allergic reactions were recorded, leading to early termination of the study. Conclusions: Although this was an unsuccessful attempt to formulate an acrylate/methacrylate mix, our experience will be useful for those embarking on future attempts to do this. (Less)

Background: Traditionally, contact allergy to aluminium has been established by patch testing with aluminium chloride hexahydrate in petrolatum at 2.0% and an empty Finn Chamber®. Objectives: The aim of this study was to investigate different aluminium test preparations regarding an optimal compound and an optimal test concentration. Methods. Six different aluminium compounds and an empty Finn Chamber® were used to patch test 21 patients with aluminium contact allergy. Aluminium chloride hexahydrate in saline was used for intracutaneous injection of 19 patients. Results: One test preparation, aluminium lactate 2.4%, was found to show significantly more positive patch test reactions than aluminium chloride hexahydrate 2.0% (p = 0.03). Aluminium chloride hexahydrate at 10.0% pet. gave the highest number of positive reactions to aluminium [14/21 (67%)]. No positive reactions were noted to an empty Finn Chamber®, and 3 of 19 (16%) patients reacted positively to the intradermal test. Conclusions: The results of this study indicate that patch testing with aluminium chloride hexahydrate 2.0%, with an empty Finn Chamber® and the intradermal test with the salt and doses used are insufficient methods to detect contact allergy to aluminium. Aluminium chloride hexahydrate at 10.0% gave the highest number of positive reactions to aluminium. (Less)

BACKGROUND: Among the textile dyes, disperse dyes are common sensitizers. OBJECTIVE: To investigate whether patch testing with a textile dye mix consisting of eight disperse dyes would be equivalent to testing with the separate ingredients of the mix at the concentrations used in the mix. METHODS: Researchers tested 1,780 consecutive patients with a mix consisting of Disperse Blue 35, Disperse Yellow 3, Disperse Orange 1, Disperse Orange 31 (mislabeled as Disperse Orange 3), Disperse Red 1 and 17, all at 0.5%, and Disperse Blue 106 and 124, both at 0.1%, and with the ingredients at these concentrations. Testing with the labeled dyes at 1.0% was done on 500 of the patients and additionally on the remaining patients who reacted positively to the mix, any of the ingredients, p-phenylenediamine, or black rubber mix. RESULTS: Thirty-five patients (2%) reacted to the mix, and 34 patients were allergic to at least one ingredient tested at the lower concentration. CONCLUSION: The textile dye mix was as good a detector of contact allergy to the disperse dyes as was testing with any combination of the ingredients at the concentration in the mix. Increasing the concentration of the ingredients of the textile dye mix might increase the sensitivity of the mix. (Less)

Background: No studies to specifically determine the prevalence of contact allergy to acrylates/methacrylates in patch tested populations have been published. Objectives: To determine the prevalence of acrylate/methacrylate allergy in all patients tested to the baseline patch test series. Methods: Five acrylate/methacrylate allergens (2-hydroxyethyl methacrylate, methyl methacrylate, ethylene glycol dimethacrylate, triethylene glycol diacrylate, and 2-hydroxypropyl acrylate) were included in the baseline series for at least 2 years in Malmo and Singapore. Results: Thirty-eight patients in total had reacted to acrylate/methacrylate allergens in the baseline series during the study period in both populations. In Malmo, there were 26 (1.4%) patients with positive patch tests to acrylate/methacrylate allergens, 14 of whom had relevant reactions. In Singapore, there were 12 (1.0%) patients with positive patch tests to acrylate/methacrylate allergens, but only 1 had relevant reactions. If we had not added acrylate/methacrylate allergens to the baseline series, we would not have patch tested 13/26 (50%) of the positive reactors in Malmo and 11/12 (92%) of the positive reactors in Singapore. The overall proportion of missed positive reactors would have been 24/38 (63%). Conclusions: The prevalence of acrylate/methacrylate allergy in our patch tested dermatitis populations is 1.4% in Malmo and 1.0% in Singapore.

Background: There are very few reports of airborne allergic contact dermatitis from methacrylates. Objectives: To report a dental nurse with facial eczema supposedly caused by airborne methacrylates present in the work environment. Methods: Patch testing with serial dilutions of several methacrylates and work provocations in environments containing methacrylates was performed. Results: Patch testing with serial dilutions of several methacrylates disclosed a high patch test reactivity. Repeated provocations when working with methacrylates resulted in facial eczema that resolved out of work. Attempts to collect the sensitizers using air pumps for the collection of vapors and filters for the collection of air-born aerosols failed. Conclusions: The clinical presentation was that of a facial dermatitis due to airborne exposure to methacrylates. It seems likely that 1 or several of these allergens caused the dermatitis. (Less)

Patients with contact allergy to sesquiterpene lactones (SLs) are usually hypersensitive to Asteraceae plant products such as herbal teas. The objective of this study was to show sensitizers in chamomile tea by patch testing with thin-layer chromatograms. Tea made from German chamomile was separated by thin-layer chromatography. Strips of the thin-layer chromatograms were used for patch testing SL-positive patients. 15 (43%) of 35 patients tested positively to 1 or more spots on the thin-layer chromatogram, with many individual reaction patterns. Patch testing with thin-layer chromatograms of German chamomile tea showed the presence of several allergens.

We report a case of a chemical burn from dipropylene glycol diacrylate (DPGDA) spilt on working shoes, followed by active sensitization, thus giving an occupational allergic contact dermatitis on the patient's dorsal feet. Diagnostic tests included patch testing with acetone extracts made from the different shoe layers and thin-layer chromatograms. An invisible spot on the thin-layer chromatography plate gave a test eczema and was further investigated with gas chromatography-mass spectrometry. DPGDA was detected in the spot.

In a recent study we showed that all our dental personnel/patients were detected with 2-hydroxyethyl methacrylate (2-HEMA) and 2,2-bis[4-(2-hydroxy-3-methacryloxypropoxy)phenyl]propane (bis-GMA). We studied 90 patients tested to the acrylate and nail acrylics series at our department over a 10 year period to see whether screening allergens could be found. Patch testing with an acrylate and nail acrylics series was performed. Among the 10 acrylate/methacrylate-allergic occupational dermatitis patients tested to the acrylate series, the most common allergens were triethyleneglycol diacrylate (TREGDA, 8), diethyleneglycol diacrylate (5), and 1,4-butanediol diacrylate (BUDA, 5). All 10 of these patients would have been picked up by a short screening series combining TREGDA, 2-hydroxypropyl methacrylate (2-HPMA), and BUDA or 1,6-hexanediol diacrylate (HDDA). Among the 14 acrylate/methacrylate-allergic nail patients, the most common allergens were ethylene glycol dimethacrylate (EGDMA, 11), 2-HEMA, (9), and triethyleneglycol dimethacrylate (9). Screening for 3 allergens i.e. 2-HEMA plus EGDMA plus TREGDA, would have detected all 14 nail patients. A short screening series combining 2-HEMA, EGDMA, TREGDA, 2-HPMA, bis-GMA, and BUDA or HDDA would have picked up all our past study patients (dental, industrial, and nail) with suspected allergy to acrylate/methacrylate allergens.

Recently, the preservative methyldibromo glutaronitrile (MDBGN) at 0.5% w/w in petrolatum was included in the European standard patch test series based on the studies on chemical stability and consideration of rates of contact allergy, doubtful and irritant reactions as well as information on clinical relevance represented by results of a repeated open application test (ROAT) and patch test concentrations required to diagnose allergic contact dermatitis from MDBGN in individual cases. In this report, a case with a clinically relevant contact allergy to MDBGN, which on the mandatory reading occasion on D3 only was traced by a patch test with MDBGN at 1.0% (0.32 mg/cm2), is presented. The patient suffered from a chronic hand dermatitis, and when the patient stopped using a liquid soap containing MDBGN, the hand dermatitis substantially improved. A ROAT performed in a blinded and controlled way with applications twice daily on the hands with 2 moisturizers with and without MDBGN resulted in a deterioration of the hand dermatitis on the hand to which the MDBGN-preserved moisturizer had been applied.

Background: Isocyanates with the general formula R-(N=C=O) are theoretically contact sensitizers. However, allergic contact dermatitis (ACD) from isocyanates is seldom reported. In previous reports, patients reacted to their isocyanate-based work materials but not to commercial patch-test preparations of isocyanates. Therefore, we suspected that the low frequency of reported ACD from isocyanates was partly due to inadequate commercial preparations. A past study also showed the concentrations of diphenylmethane-4,4'-diisocyanate (4,4'-MDI) in petrolatum preparations to be much lower than declared. Objective: In this study, 2,4-toluene diisocyanate (2,4-TDI), 1,6-hexamethylene diisocyanate (1,6-HDI), and isophorone diisocyanate (IPDI) were investigated in a similar fashion. Methods: In preparations from 12 dermatology departments and two suppliers of patch-test allergens, we determined the isocyanate content as the isocyanate-dibutylamine derivative, using liquid chromatography and mass spectrometry. The preparations were considered stable if the ratio between the stated and found concentrations was within the range of 0.8 to 1.2. Results: Although 28 of 36 investigated preparations had ratios outside of the stable range, they were in its vicinity, which indicates that preparations of 2,4-TDI, 1,6-HDI, and IPDI are more stable than are preparations of 4,4'-MDI where previously reported results showed ratios far outside of stable range. Conclusion: As opposed to preparations of 4,4'-MDI, preparations of 2,4-TDI, 1,6-HDI, and IPDI can be considered to be stable. (Less)

The authors report a case study of a contact allergy due to occupational exposure to plastics used in orthopaedic engineering.

Three cases of allergic contact dermatitis localized to the sites of electrocardiograph-monitoring electrodes are reported. All patients had positive patch tests to both the gel and the adhesive part of the Red Dot 2239 3M monitoring electrode used and to the p-tert-butylphenol-formaldehyde resin (PTBP-F-R) of the standard series. Two patients had a history of possible exposition to the resin previously but there was no explanation for the third. No information about the presence of PTBP-F-R in the electrodes could be obtained from the manufacturers. Chemical analysis of samples of the electrode, using a gas chromatography-mass spectrometry (GC-MS) and high pressure liquid chromatography (HPLC) analytical system, demonstrated the presence of several PTBP-F-R derivatives in both the gel and the adhesive part.

In this study, the sensitizing capacities of the 3 main low-molecular-weight isomers of epoxy resins based on diglycidyl ether of biphenol F (DGEBF) were investigated in a guinea pig maximization test (GPMT). The isomers are p,p'-DGEBF, o,p'-DGEBF, and o,o'-DGEBF. The sensitization capacities were compared to diglycidyl ether of bisphenol A (DGEBA), which is the main constituent in the most common epoxy resin. The cross-reaction pattern between all 4 compounds was also investigated. It was found that all 3 DGEBF isomers were potent sensitizers. It was also found that p,p'-DGEBF, o,p'-DGEBF, and DGEBA cross-reacted with one another, and that animals induced with o,o'-DGEBF reacted significantly only to o,p'-DGEBF, but not to the other 2 DGEBF isomers or DGEBA.

In many adhesive formulations p-tert-butylphenol-formaldehyde resin (PTBP-F-R) is used as a binder. Contact allergy to this resin is not rare. In patients hypersensitive to PTBP-F-R, and butylphenol derivatives therein, it is for diagnostic and preventive reasons necessary to know the nature of the primary sensitizing substances, as well as the cross-reaction patterns for these. The aim of this study was to investigate contact allergy to monomers in PTBP-F-R and potential cross-reacting substances. 12 patients hypersensitive to PTBP-F-R were patch tested with 2 monomers, the raw materials formaldehyde and p-tert-butylphenol, and 3 closely related substances. High pressure liquid chromatography (HPLC) was used to investigate the purity of the test substances. It was shown that the monomers 2-methylol p-tert-butylphenol and 2,6-dimethylol p-tert-butylphenol could elicit allergic reactions in humans hypersensitive to PTBP-F-R. No simultaneous reactions or cross-reactions were shown to formaldehyde, p-tert-butylphenol, p-tert-butylcatechol, 2(3)-tert-butyl-4-hydroxyanisole (BHA) or 3,5-di-tert-butyl-4-hydroxytoluene (BHT). It was also shown that low amounts of contaminants in the test substances, if not taken into account, could influence the conclusions drawn from the test results obtained.

Contact allergy to p-tert-butylphenol formaldehyde resin (PTBP-F-R) is not rare. This resin consists of a large number of substances, most of which are still unknown. For diagnostic and preventive reasons the chemical identity of the sensitizers should be known, as well as their sensitizing capacities, cross-reaction patterns and presence in the environment. The aims of this study were to investigate the sensitizing capacities and potential cross-reacting patterns for 4-tert-butyl- 2,6-bis-(5-tert-butyl-2-hydroxy-3-hydroxymethyl-benzyloxymethyl)-phenol (XIII), 4-tert-butyl-2- (5 - tert - butyl - 2 - hydroxy-benzyloxymethyl) - 6 - (5 - tert - butyl - 2 - hydroxy - 3 - hydroxymethyl-benzyloxy methyl)-phenol (XIVa) and 7,15,23-tri-tert-butyl-25,26,27-trihydroxy-2,3,10,11,18,19-hexahomo-3,11,19-trioxacalix(3)arene (XVIII) by the guinea pig maximization test. 4-tert-Butyl-2,6-bis-hydroxymethyl-phenol, 4-tert-butylbenzene-1,2-diol, 4-tert-butyl-2-hydroxymethyl-phenol, 4-tert-butyl-phenol, 4-tert-butyl-2-(5-tert-butyl-2-hydroxy-3-hydroxymethyl-benzyloxymethyl)-6-hydroxymethyl-phenol, 4-tert-butyl-2-[5-tert-butyl-3-(5-tert-butyl-2-hydroxy-3-hydroxymethyl-benzyloxymethyl) - 2 -hydroxy-benzyloxymethyl] - 6 - (5 - tert-butyl- 2 -hydroxy- 3 -hydroxymethyl-benzyloxymethyl)- phenol and were used as potential cross-reacting substances. In this study it is strongly indicated that the linear trimer XIII has a sensitizing capacity in the guinea pig which was significant when compared to the controls (p = 0.024). No cross-reactions were detected in animals induced with the linear trimer XIII. The linear trimer XIVa and the cyclic trimer XVIII failed to induce sensitization.