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Background: Prophylactic vaccination against influenza and other epidemic viruses is recommended for citizens above 65 years. Several vaccines may contain traces of formaldehyde and are contra-indicated in patients hypersensitive (in the broadest possible meaning) to formaldehyde. Thorough knowledge on the various subtypes of hypersensitivity is sparse among non-dermatologists and non-allergists, and therefore many patients are prevented from vaccination based on a positive patch test to formaldehyde. The purpose of this retrospective study was to investigate whether patients with positive patch test to formaldehyde subsequently receiving a formaldehyde-containing vaccine and developed a severe adverse reaction., Methods/materials: From January 2000 to June 2021, 169 patients (>50 years) had a positive formaldehyde patch test at the Department of Dermatology and Allergy Center, Odense University Hospital and were included into this retrospective study. The electronic medical record was assessed for receipt of a formaldehyde-containing vaccine after patch test and for subsequent contact with the Acute Ward in the Region of Southern Denmark within 14 days after vaccination., Results: Of the 158 patients residing in the Region of Southern Denmark, 130 patients were vaccinated with one or more formaldehyde-containing vaccines of whom 123 received an influenza vaccine. No contacts to the acute wards were identified., Discussion: Although prospective studies would be beneficial, patients with positive patch test to formaldehyde can be safely vaccinated with formaldehyde-containing vaccines., (© 2023 The Authors. Contact Dermatitis published by John Wiley & Sons Ltd.)

Background: Eugenol is a known contact sensitiser included in fragrance mix I., Objective: To assess the allergic reactivity to eugenol in different concentrations using patch test as well as repeated open application test (ROAT)., Methods: Overall 67 subjects from 6 European dermatology clinics participated in the study. The ROAT was performed for 21 days twice a day, applying 3 dilutions of eugenol (2.7%-0.5%) and a control. Before and after the ROAT, patch testing with 17 dilutions of eugenol (2.0%-0.00006%) and controls was performed., Results: Out of the 34 subjects with contact allergy to eugenol, 21 (61.8%) showed a positive patch test before ROAT was performed, the lowest positive concentration was 0.031%. The ROAT was positive in 19 (55.9%) of the 34 subjects, the time until a positive reaction occurred was negatively associated with the concentration of the ROAT solution, as well as with the allergic reactivity of the subjects as defined by patch testing. In the patch test after ROAT, 20 of the 34 test subjects (58.8%) showed a positive reaction. In 13 (38.2%) of the 34 test subjects, the patch test result was not reproduceable, still 4 (31.0%) of these 13 subjects developed a positive ROAT., Conclusion: Eugenol can provoke a positive patch test reaction in a very low dose; besides, this hypersensitivity may persist even if a former positive patch test is not reproduceable., (© 2023 The Authors. Contact Dermatitis published by John Wiley & Sons Ltd.)

Background: Insulin pumps and glucose monitoring devices improve diabetes mellitus control and enhance patients' quality of life. However, a growing number of adverse cutaneous reactions related to the use of these devices have been reported., Objective: To investigate the culprits of localized contact dermatitis in paediatric patients with diabetes caused by insulin pumps and glucose monitoring devices., Methods: Retrospective analysis of 15 paediatric patients patch tested as part of a clinical investigation for skin reactions associated with insulin pumps and glucose monitoring devices., Results: Seven patients had positive patch test reactions to isobornyl acrylate (IBOA) and five had positive reactions to benzoyl peroxide (BP). Positive patch test reactions to materials from the glucose sensor and/or insulin pump were seen in 10 of the 15 patients. Three had positive reactions to adhesive remover wipe from Smith and Nephew Remove and four had reactions to EMLA plaster., Conclusion: A high share of patients showed positive reactions to IBOA and/or their medical devices (insulin pumps or glucose devices). A third of patients showed positive reactions to BP. The presence of additional unidentified allergens cannot be excluded, highlighting the importance of access to a full description of the chemical composition of the devices., (© 2022 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: Hand eczema is a common inflammatory skin disorder. Health care providers need continuously updated information about the management of hand eczema to ensure best treatment for their patients., Objectives: To update the European Society of Contact Dermatitis guideline on the diagnosis, prevention, and treatment on of hand eczema., Method: The Guideline Development Group (GDG) was established on behalf of the ESCD. A call for interest was launched via the ESCD website and via the ESCD members' mailing list. Appraisal of the evidence for therapeutic and preventive interventions was applied and a structured method of developing consensus was used and moderated by an external methodologist. The final guideline was approved by the ESCD executive committee and was in external review on the ESCD webpage for 1 month., Results: Consensus was achieved for several statements and management strategies., Conclusion: The updated guideline should improve management of hand eczema., (© 2021 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: Compositae plant sensitization in children is relatively frequent. From 1995-2006, we found a prevalence of 1.8% sesquiterpene lactone (SL) mix/parthenolide patch test positives among consecutive eczema patients <18 years., Objectives: To report the results of patch test screening for Compositae sensitization in patients <18 years in the last 13 years., Methods: Children and adolescents <18 years, diagnosed with Compositae sensitization between 2007 and 2019, were included., Results: Among 388 children tested, 12 (3%) were Compositae-sensitized, and 11 (2.8%) had positive reactions to SL mix. Compositae mix 5% pet. elicited positive reactions in six of seven patients tested, and dandelion extract 2.5% pet. in six of 10 patients tested. The mean age of the five girls and seven boys was 9.4 years and 11.7 years, respectively. Eleven children had a personal and one a family history of atopy, and 11 children had hand eczema. Only two were mono-sensitized to Compositae., Conclusions: SL mix is a suitable screening agent among children and adolescents in our area, well supplemented with Compositae mix 5% and dandelion extract. The study emphasizes the importance of Compositae screening in children with a personal and/or family history of atopy, hand eczema or widespread airborne dermatitis, summer exacerbation, and plant exposure., (© 2020 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: Both florists' chrysanthemums (Chrysanthemum cultivars) and marguerite daisies (Argyranthemum frutescens [L.] Sch.Bip. and its varieties and cultivars) are popular ornamental plants in Denmark., Objectives: To present results of aimed patch testing with chrysanthemum and marguerite daisy extracts in Danish patients with Compositae sensitization., Methods: The results of patch testing with chrysanthemum extract 3% petrolatum (pet.) and marguerite daisy extract 3% pet. (and possibly 1% pet.) from 1998 to 2019 were analyzed., Results: Altogether, 111/191 (58%) patients tested positive to chrysanthemum extract and 104/179 (58%) tested positive to marguerite daisy. The majority was recreationally exposed, and most reactions were considered relevant. Feverfew extract 1% pet., Compositae mix 5% or 6% pet., or parthenolide 0.1% pet. may cross-react with chrysanthemum; Compositae mix seems to be best at detecting sensitization to marguerite daisy., Conclusions: In areas where exposure to chrysanthemum or marguerite daisies is prevalent, it is suggested to include extracts of these plants in the plant series to improve diagnosis of, and advice to, Compositae-allergic patients., (© 2019 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: Compositae contact sensitization may be difficult to diagnose, because of a lack of reliable screening allergens., Objectives: To assess the suitability of Compositae mix II 2.5% pet. (CM2.5) as a screening mix in the baseline series combined with sesquiterpene lactone (SL) mix and parthenolide (PTH)., Methods: CM2.5 was added to the baseline series, which included SL mix and PTH 0.1% pet., in January 2015, and PTH was included in TRUE Test Panel 3 in October 2015. All Compositae-sensitive patients diagnosed or tested in the next 4 years were assessed., Results: Altogether, 57 patients (2.7%) presented with Compositae allergy. On primary testing in 53 newly diagnosed patients, SL mix elicited positive reactions most frequently (53% positive), followed by CM2.5 (47% positive), and PTH (45% positive). CM2.5 and PTH pet. elicited a few irritant reactions. Three patients had late reactions. Altogether, 16 patients (28%) were not detected by any of the three screening agents., Conclusions: SL mix is an indispensable, although insufficient, screening mixture in Denmark. It may be relatively safely supplemented with CM2.5 and PTH in the TRUE Test system for screening, but, when Compositae sensitization is suspected, further extracts should be tested on the basis of the history., (© John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

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., (© 2019 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: The sunflower family of plants (Compositae = Asteraceae) is currently the most allergenic plant family worldwide, according to the number of sensitizing species. Secondary plant metabolites, including the allergenic sesquiterpene lactones present in Compositae plants, may occur in food items either through their presence in, or through contamination of, plant-based raw materials, or through their occurrence in products of non-plant origin., Objective: To analyse biodynamic, organic and conventional milk for the presence of the sesquiterpene lactone parthenolide., Methods: The content of parthenolide in the milk samples was investigated in dichloromethane extracts obtained by liquid-liquid extraction, followed by gas chromatography-mass spectrometry analyses., Results: The concentration of parthenolide was 0.07 ±0.004 ppm in biodynamic milk, 0.05 ±0.002 ppm in organic milk, and not detectable (<0.002 ppm) in conventional milk., Conclusions: This is the first report of a potent contact allergen in milk. There seems to be an association between the time that the dairy cattle spend grazing and the amount of parthenolide detected. Although the concentration is low, it is estimated to be high enough to elicit dermatitis in the most sensitive persons by direct contact with the milk., (© 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: Concern about causing active sensitization when patch testing is performed with p-phenylenediamine (PPD) 1% pet. has led to a recommendation to use PPD 0.3% pet. as a potentially safer preparation. However, the dose per area of allergen delivered, and hence the risk of active sensitization, depend on the amount dispensed into the patch test chamber, which can vary widely., Objective: To evaluate whether patch testing with equivalent doses of different concentrations of PPD in pet. is associated with similar outcomes., Methods: Seventeen known PPD-sensitive subjects were patch tested with different volumes and concentrations of PPD in pet. that deliver the same allergen dose per unit area (6 mg of PPD 1% pet. and 20 mg of PPD 0.3% pet. in Finn Chambers®, both equivalent to ∼ 0.09 mg/cm 2 )., Results: Eleven patients (65%) had positive reactions to both doses; 4 patients (24%) had negative results [percentage agreement of 88% (15/17)]. One patient each had a positive reaction to only one dose., Conclusions: The 88% concordance suggests that dose per unit area is more important in determining reactions to allergens than the excipient volume dispensed. Patch testing with a smaller volume of 1% PPD may be a reasonable alternative to testing with 20 mg of 0.3% PPD., (© 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: Allergic contact dermatitis (ACD) caused by nail acrylates, also including methacrylates and cyanoacrylates here, is being increasingly reported., Methods: A retrospective study in 11 European Environmental Contact Dermatitis Research Group (EECDRG) clinics collected information on cases of ACD caused by nail acrylates diagnosed by aimed testing between 2013 and 2015., Results: Among 18 228 studied patients, 136 had ACD caused by nail acrylates (0.75%; 95%CI: 0.60-0.90), representing 67.3% (95%CI: 60.4-73.7) of ACD cases caused by acrylates. There were 135 females and 1 male, with a mean age ± standard deviation of 36.7 ± 12.2 years; 59 (43.4%) were exposed as consumers, and 77 (56.6%) were occupationally exposed. Occupational cases were more frequent in southern Europe (83.7%), and were younger (mean age of 33.4 ± 8.9 years); most developed ACD during the first year at work (65.0%), and at least 11.7% had to leave their jobs. Skin lesions involved the hands in 121 patients (88.9%) and the face in 50 (36.8%), with the face being the only affected site in 14 (10.3%). Most patients reacted to two or more acrylates on patch testing, mainly to 2-hydroxyethyl methacrylate (HEMA) (92.5%), 2-hydroxypropyl methacrylate (88.6%), ethylene glycol dimethacrylate (69.2%), and ethyl cyanoacrylate (9.9%)., Conclusions: Nail cosmetics were responsible for the majority of ACD cases caused by acrylates, affecting nail beauticians and consumers, and therefore calling for stricter regulation and preventive measures. As HEMA detects most cases, and isolated facial lesions may be overlooked, inclusion of this allergen in the baseline series may be warranted., (© 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: Compositae dermatitis was originally described as airborne contact dermatitis. More recent studies have reported a wider clinical spectrum, but often in polysensitized patients., Objective: To evaluate the clinical features of patients sensitized to Compositae only., Patients/methods: Consecutive Compositae-sensitive eczema patients, tested between 1990 and 2015, who, at the patch testing session diagnosing their Compositae allergy, were found to be sensitized only to the plant family, were included., Results: Altogether, 529 of 13 139 patients tested (4.0%) were sensitized to Compositae, and 95 (18% of these) were monosensitized. The majority had hand eczema, and 39 (44%) had a vesicular volar pattern. Eighty-one patients were classified into one of three groups of similar size: localized eczema, eczema of exposed skin, and localized eczema turning into widespread eczema., Conclusions: The prevalence of Compositae sensitization is continuously high in consecutive eczema patients. Sensitization may occur at any age. Clinical features in monosensitized patients vary, but, with continuing exposure, the patients may develop more widespread dermatitis similar to classic Compositae dermatitis. Avoidance may clear the exogenous part, but not endogenous aetiological factors such as vesicular hand eczema or possible photosensitivity. Thorough clinical assessment and patient education are important in reducing the impact of Compositae contact allergy., (© 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: The Australian cushion bush (Leucophyta brownii) of the Compositae family of plants has become a popular pot and container plant. The plant produces the sesquiterpene lactone allergen calocephalin., Objectives: To assess the sensitizing potential of sesquiterpene lactones from cushion bush., Patients/materials/methods: Eleven Compositae-sensitive patients were patch tested with seven sesquiterpene lactones isolated from cushion bush., Results: Six of seven sesquiterpene lactones elicited positive reactions in 4 of 11 patients., Conclusions: The well-known sesquiterpene lactone pseudoivalin and its derivative pseudoivalin acetate, as well as calocephalin and tomentosin, were confirmed to be sensitizers, whereas leucophytalin A and 4α-hydroxy-5αH,10αH-1,11(13)-guaidien-8β,12-olide were shown to be allergenic for the first time. The patch test reaction patterns seem to follow the chemical patterns, which may eventually make it possible to trace primary sensitizers and advise patients more precisely., (© 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: The use of methylisothiazolinone (MI) in cosmetic products has caused an unprecedented epidemic of MI contact allergy. Current data concerning exposures at a European level are required., Objectives: To describe demographics and MI exposures for European patients with MI contact allergy., Methods: Eleven European dermatology departments from eight European countries prospectively collected data between 1 May and 31 October 2015 among consecutive patients who had positive patch test reactions to MI (2000 ppm aq.)., Results: A total of 6.0% (205/3434; range 2.6-13.0%) of patients had positive patch test reactions to MI. Dermatitis most frequently affected the hands (43.4%), face (32.7%), arms (14.6%), and eyelids (11.7%); 12.7% had widespread dermatitis. For 72.7% (149/205), MI contact allergy was currently relevant mainly because of exposure to cosmetic products (83.2%; 124/149). Of these 124 patients, 19.5% were exposed to leave-on and rinse-off cosmetic products, 24.8% only to leave-on cosmetic products and 38.9% only to rinse-off cosmetic products containing MI or methylchloroisothiazolinone/MI. The majority of these (79%) noted onset of their dermatitis between 2013 and 2015. Fifteen patients (7.3%) had previously experienced allergic reactions when they were in newly painted rooms., Conclusion: Clinically relevant MI contact allergy remains prevalent across European countries, mainly because of exposure to rinse-off and leave-on cosmetic products., (© 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: Limonene and linalool are common fragrance terpenes. Both oxidized R-limonene and oxidized linalool have recently been patch tested in an international setting, showing contact allergy in 5.2% and 6.9% of dermatitis patients, respectively., Objective: To investigate concomitant reactions between oxidized R-limonene and oxidized linalool in consecutive dermatitis patients., Methods: Oxidized R-limonene 3.0% (containing limonene hydroperoxides 0.33%) and oxidized linalool 6% (linalool hydroperoxides 1%) in petrolatum were tested in 2900 consecutive dermatitis patients in Australia, Denmark, Singapore, Spain, Sweden, and the United Kingdom., Results: A total of 281 patients reacted to either oxidized R-limonene or oxidized linalool. Of these, 25% had concomitant reactions to both compounds, whereas 29% reacted only to oxidized R-limonene and 46% only to oxidized linalool. Of the 152 patients reacting to oxidized R-limonene, 46% reacted to oxidized linalool, whereas 35% of the 200 patients reacting to oxidized linalool also reacted to oxidized R-limonene., Conclusions: The majority of the patients (75%) reacted to only one of the oxidation mixtures, thus supporting the specificity of the reactions. The concomitant reactions to the two fragrance allergens suggest multiple sensitizations, which most likely reflect the exposure to the different fragrance materials in various types of consumer products. This is in accordance with what is generally seen for patch test reactions to fragrance materials., (© 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Lettuce (Lactuca sativa L.) and its varieties are important vegetable crops worldwide. They are also well-known, rarely reported, causes of contact allergy. As lettuce allergens and extracts are not commercially available, the allergy may be underdiagnosed. The aims of this article are to present new data on lettuce contact allergy and review the literature. Lettuce is weakly allergenic, and occupational cases are mainly reported. Using aimed patch testing in Compositae-allergic patients, two recent Danish studies showed prevalence rates of positive lettuce reactions of 11% and 22%. The majority of cases are non-occupational, and may partly be caused by cross-reactivity. The sesquiterpene lactone mix seems to be a poor screening agent for lettuce contact allergy, as the prevalence of positive reactions is significantly higher in non-occupationally sensitized patients. Because of the easy degradability of lettuce allergens, it is recommended to patch test with freshly cut lettuce stem and supplement this with Compositae mix. As contact urticaria and protein contact dermatitis may present as dermatitis, it is important to perform prick-to-prick tests, and possibly scratch patch tests as well. Any person who is occupationally exposed to lettuce for longer periods, especially atopics, amateur gardeners, and persons keeping lettuce-eating pets, is potentially at risk of developing lettuce contact allergy., (© 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: Allergic contact dermatitis resulting from the use of permanent hair dyes is common. Approximately 100 hair dye chemicals are permitted in Europe. Hair dye ingredients may change over time, and hence new hair dye allergens should be looked for continuously., Objectives: To review positive patch test reactions to the coupler 2-amino-4-hydroxyethylaminoanisole sulfate 2% pet. from 2005 to 2014., Methods: Patch test results from the Allergen Bank database for eczema patients patch tested with 2-amino-4-hydroxyethylaminoanisole sulfate 2% pet. from 2005 to 2014 were reviewed., Results: A total of 902 dermatitis patients (154 from the dermatology department and 748 from 65 practices) were patch tested with amino-4-hydroxyethylaminoanisole sulfate 2% pet. from 2005 to 2014. Thirteen (1.4%) patients had a positive patch test reaction. Our results do not indicate irritant reactions., Conclusions: 2-Amino-4-hydroxyethylaminoanisole sulfate is a new but rare contact allergen., (© 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

The present guideline summarizes all aspects of patch testing for the diagnosis of contact allergy in patients suspected of suffering, or having been suffering, from allergic contact dermatitis or other delayed-type hypersensitivity skin and mucosal conditions. Sections with brief descriptions and discussions of different pertinent topics are followed by a highlighted short practical recommendation. Topics comprise, after an introduction with important definitions, materials, technique, modifications of epicutaneous testing, individual factors influencing the patch test outcome or necessitating special considerations, children, patients with occupational contact dermatitis and drug eruptions as special groups, patch testing of materials brought in by the patient, adverse effects of patch testing, and the final evaluation and patient counselling based on this judgement. Finally, short reference is made to aspects of (continuing) medical education and to electronic collection of data for epidemiological surveillance., (© 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: In the 1980s, a striking increase in natural rubber latex (NRL) allergy was seen. Since then, many measures have been taken to prevent NRL allergy., Objectives: To investigate changes in the prevalence of NRL sensitization/clinical NRL allergy over time from 2002 to 2013., Methods: All patients prick tested for NRL at the Department of Dermatology and Allergy Centre, Odense University Hospital were included in this study (n = 8580). In NRL-sensitized patients, the clinical relevance was evaluated for NRL. Furthermore, concomitant positive prick test results for birch pollen were recorded, together with food-related symptoms and sensitization in a subgroup of patients., Results: The prevalence of NRL sensitization declined from 6.1% in 2002-2005 to 1.9% in 2006-2009, and then to 1.2% in 2010-2013 (p < 0.0001). The prevalence of clinical NRL allergy declined from 1.3% in 2002-2005 to 0.5-0.6% in 2006-2013 (p < 0.004). Among the NRL-sensitized patients, 64% had a concomitant positive prick test reaction to birch pollen, and 52% had a history of reaction to oral intake of related fruits or vegetables., Conclusion: Our study showed a statistically significant decline in the number of patients sensitized/clinically allergic to NRL. Many of the NRL-sensitized patients without clinical allergy to NRL had concomitant birch pollen sensitization, and reported food-related symptoms., (© 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: Sunflowers may cause dermatitis because of allergenic sesquiterpene lactones (SLs). Contact sensitization to sunflower seeds has also been reported, but the allergens are unknown., Objectives: To analyse sunflower seeds for the presence of SLs and to assess the prevalence of sunflower sensitization in Compositae-allergic individuals., Patients/materials/methods: Sunflower-sensitive patients were identified by aimed patch testing. A dichloromethane extract of whole sunflower seeds was analysed by liquid chromatography-mass spectrometry and high-performance liquid chromatography., Results: The prevalence of sensitivity to sunflower in Compositae-allergic individuals was 56%. A solvent wash of whole sunflower seeds yielded an extract containing SLs, the principal component tentatively being identified as argophyllin A or B, other SLs being present in minute amounts., Conclusions: The concentration of SLs on the sunflower seeds is considered high enough to elicit dermatitis in sensitive persons, and it seems appropriate to warn Compositae-allergic subjects against handling sunflower seeds., (© 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: Oak moss absolute, an extract from the lichen Evernia prunastri, is a valued perfume ingredient but contains extreme allergens., Objectives: To compare the elicitation properties of two preparations of oak moss absolute: 'classic oak moss', the historically used preparation, and 'new oak moss', with reduced contents of the major allergens atranol and chloroatranol., Patients/materials/methods: The two preparations were compared in randomized double-blinded repeated open application tests and serial dilution patch tests in 30 oak moss-sensitive volunteers and 30 non-allergic control subjects., Results: In both test models, new oak moss elicited significantly less allergic contact dermatitis in oak moss-sensitive subjects than classic oak moss. The control subjects did not react to either of the preparations., Conclusions: New oak moss is still a fragrance allergen, but elicits less allergic contact dermatitis in previously oak moss-sensitized individuals, suggesting that new oak moss is less allergenic to non-sensitized individuals., (© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: Recently, sodium tetrachloropalladate (Na2 PdCl4 ) was found to be a more sensitive palladium patch test allergen than palladium dichloride (PdCl2 )., Objectives: To determine the optimal test concentration of Na2 PdCl4 , to evaluate the prevalence of palladium sensitization with Na2 PdCl4 and PdCl2 , and to compare the results with nickel sensitization in a European multicentre study., Materials and Methods: In addition to the European or national baseline series including NiSO4 ·6H2 0 5% pet., consecutive patients were tested with PdCl2 and Na2 PdCl4 2%, 3% and 4% pet. in eight European dermatology clinics. The age and sex distributions were also evaluated in patients sensitized to nickel and palladium., Results: In total, 1651 patients were tested. Relative to 3% Na2 PdCl4 , 4% Na2 PdCl4 did not add any information. Two per cent Na2 PdCl4 resulted in more doubtful reactions and showed suboptimal reactivity. The prevalence of palladium sensitization doubled with Na2 PdCl4 and was similar to that of nickel. Interestingly, in contrast to nickel sensitization, palladium sensitization was not related to female sex., Conclusions: Three per cent Na2 PdCl4 pet. is the most suitable patch test concentration. Sensitization to palladium is almost as prevalent as sensitization to nickel. The sex distribution is different between nickel-sensitized and palladium-sensitized patients, suggesting different sources of exposure., (© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: Blue-collar workers have a high risk of occupational contact dermatitis, but epidemiological studies are scarce., Objectives: To investigate allergic contact dermatitis in blue-collar workers with dermatitis registered by the Danish Contact Dermatitis Group., Methods: A retrospective analysis of patch test data from 1471 blue-collar workers and 1471 matched controls tested between 2003 and 2012 was performed. A logistic regression was used to test for associations., Results: The blue-collar workers often had occupational hand dermatitis (p < 0.001). Atopic dermatitis was less commonly observed among blue-collar workers (19.6%) than among controls (23.9%) (p = 0.005). Allergens with a statistically significant association with the occupational group of blue-collar workers were epoxy resins, methyldibromo glutaronitrile, 2-bromo-2-nitro-1,3-propanediol, potassium dichromate, and methylchloroisothiazolinone (MCI)/methylisothiazolinone (MI). The following occupations were additionally identified as risk factors for contact sensitization to MCI/MI and MI, epoxy resins, and potassium dichromate, respectively: painting, construction work, and tile setting/terrazzo work., Conclusion: Contact allergy is a major problem among blue-collar workers. The data indicate a healthy worker effect among blue-collar workers diagnosed with dermatitis, as blue-collar workers were diagnosed significantly less often with atopic dermatitis than were controls., (© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: In recent years, the prevalence of contact allergy to isothiazolinones has reached epidemic levels. Few studies have presented data on occupations at risk of developing contact allergy to isothiazolinones., Objectives: To present demographics and examine risk factors for sensitization to methylisothiazolinone (MI), methylchloroisothiazolinone (MCI) in combination with MI and benzisothiazolinone (BIT) in Danish dermatitis patients., Materials and Methods: A retrospective epidemiological analysis of data from three Danish hospitals departments was conducted. All patients consecutively patch tested with MI, MCI/MI and BIT between 2009 and 2013 were included., Results: MI contact allergy showed a significantly increased trend in prevalence from 1.8% in 2009 to 4.2% in 2012 (p < 0.001). Females with facial dermatitis mainly drove the increase in 2012. Adjusted logistic regression analysis showed that MI sensitization was significantly associated with occupational exposures, hand and facial dermatitis, age > 40 years, and the occupational groups of tile setters/terrazzo workers, machine operators, and painters. MCI/MI contact allergy was significantly associated with the following high-risk occupations: painting, welding (blacksmiths), machine operating, and cosmetology. The occupational group of painting was frequent in the group of patients with BIT contact allergy., Conclusion: Several high-risk occupations for sensitization to isothiazolinones exist. Regulation on the allowed concentration of isothiazolinones, and especially MI, in both consumer products and industrial products is needed., (© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: R-Limonene is a common fragrance terpene found in domestic and industrial products. R-Limonene autoxidizes on air exposure, and the oxidation products can cause contact allergy. In a recent multicentre study, 5.2% (range 2.3-12.1%) of 2900 patients showed a positive patch test reaction to oxidized R-limonene., Objective: To study the exposure to limonene among consecutive dermatitis patients reacting to oxidized R-limonene in an international setting, and to assess the relevance of the exposure for the patients' dermatitis., Methods: Oxidized R-limonene 3.0% (containing limonene hydroperoxides at 0.33%) in petrolatum was tested in 2900 consecutive dermatitis patients in Australia, Denmark, the United Kingdom, Singapore, Spain, and Sweden. A questionnaire assessing exposure to limonene-containing products was completed., Results: Overall, exposure to products containing limonene was found and assessed as being probably relevant for the patients' dermatitis in 36% of the limonene-allergic patients. In Barcelona and Copenhagen, > 70% of the patients were judged to have had an exposure to limonene assessed as relevant., Conclusions: Oxidized R-limonene is a common fragrance allergen, and limonene was frequently found in the labelling on the patients' products, and assessed as relevant for the patients' dermatitis. A large number of domestic and occupational sources for contact with R-limonene were identified., (© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: Disperse dyes are well-known contact sensitizers. However, they are not included in the majority of commercially available baseline patch test series., Objectives: To investigate the outcome of patch testing with a textile dye mix (TDM) consisting of eight disperse dyes at dermatology clinics in various countries., Patients/materials/methods: Two thousand nine hundred and seven consecutive dermatitis patients at 12 dermatology clinics representing nine countries were tested with a TDM at 6.6%, consisting of Disperse Blue 35, Disperse Yellow 3, Disperse Orange 1 and 3, and Disperse Red 1 and 17, all at 1.0%, and Disperse Blue 106 and Disperse Blue 124, each at 0.3%, provisionally included in the baseline series. Eighty-seven per cent of the patients allergic to the TDM were also tested with the eight separate dyes., Results: Contact allergy to TDM was found in 108 patients (3.7%). The frequency of contact allergy varied from 2.1% to 6.9% in different centres. Simultaneous reactivity to p-phenylenediamine was found in 57 of the TDM-positive patients (53%). The most frequent dye allergen among the TDM-positive patients was Disperse Orange 3. The contact allergy could have explained or contributed to the dermatitis in approximately one-third of the patients for whom clinical relevance of the TDM contact allergy was recorded., Conclusions: The TDM should be considered for inclusion in the European baseline series., (© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)