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Background: The diagnostic significance of the atopy patch test for the management of dermatitis possibly triggered by aeroallergens is still controversial. However, sufficiently large studies with routinely tested standardized aeroallergen patch test preparations in dermatitis patients are lacking. Objective: To evaluate the reaction frequency and the reaction profiles of 10 until mid‐2015 commercially available, standardized aeroallergen patch test preparations of the 'Stallerpatch' test series (Stallergenes, Antony Cedex, France) in a large multicentre patient cohort. Methods: A retrospective data analysis of patients with suspected aeroallergen‐dependent eczematous skin lesions was performed, who were patch tested in 15 Information Network of Departments of Dermatology‐associated clinics between 2000 and 2015. Patients were stratified according to their atopic dermatitis (AD) status. Results: The study group included 3676 patients (median age 41 years, 34.8% males, 54.5% AD). The most common aeroallergens causing positive patch test reactions were Dermatophagoides pteronyssinus (19.6%), Dermatophagoides farinae (16.9%), birch (6.2%), timothy grass (6.0%), cat dander (5.4%), mugwort (4.9%) and dog dander (4.6%). Reactions to other pollen allergen preparations, that is 5 grasses (3.2%), cocksfoot (2.1%) and plantain (1.6%), were less common. Positive patch test reactions to aeroallergens were consistently more frequent in patients with AD. These patients showed proportionally less dubious, follicular, irritant and weak positive reactions. Independent of AD status, a patient history of past or present allergic rhinitis was associated with an increased chance of a positive aeroallergen patch test reaction to pollen allergens. Conclusion: The aeroallergen patch test is a useful add‐on tool in clinical routine, especially in patients with AD and/or respiratory allergy. A patch test series comprising Dermatophagoides pteronyssinus, Dermatophagoides farinae, birch, timothy grass, cat dander and mugwort seems to be suitable. Controlled studies with specific provocation and elimination procedures are required to further evaluate the diagnostic significance of the proposed screening series. [ABSTRACT FROM AUTHOR]

Summary: Background: Sodium lauryl sulfate (SLS) is the best‐studied detergent in irritant contact dermatitis. In atopic dermatitis, the two major pathophysiological abnormalities concern skin barrier function and regulation of cutaneous immune responses. The probability of atopic skin diathesis can be assessed by comprehensive analysis of patient history, as well as clinical and laboratory findings, resulting in the Erlangen Atopy Score (EAS). Objectives: To investigate the impacts of (i) atopic skin diathesis according to the EAS and (ii) the physician‐assessed diagnoses 'atopic dermatitis', 'allergic rhinitis' and 'allergic asthma' on SLS skin reactions. Methods: This is a retrospective analysis of data from 2030 consecutive patients patch tested with SLS (0·25% aqueous) from two tertiary referral centres in Germany, from 2008 to 2014. Results: Patients with a high probability of atopic skin diathesis showed no significant increase in positive SLS reactions compared with patients without atopic skin diathesis (14·2% vs. 16·8%). The grading of positive SLS skin reactions (1–4) revealed no differences in patients with or without atopic skin diathesis. Furthermore, diagnoses of atopic dermatitis, allergic rhinitis or allergic asthma had no impact on positive SLS skin reactions in multivariate logistic regression analysis. Conclusions: We found no association of increased skin irritability to SLS with atopic skin diathesis, atopic dermatitis, allergic rhinitis or allergic asthma in a large patient cohort. It therefore seems that the test of skin irritability with SLS, which is currently common practice in many centres, does not allow prediction of susceptibility to irritant eczematous inflammation in atopic vs. nonatopic individuals. What's already known about this topic? Irritant contact dermatitis and atopic skin diathesis share impaired skin barrier function as a pathophysiological pattern.Sodium lauryl sulfate (SLS) is tested at 0·25% aqueous as an irritant control in patch testing, and hence the results might be affected by atopic skin diathesis. What does this study add? Challenging a long‐standing paradigm, we found no association of increased reactivity to SLS patch tests in individuals with atopic skin diathesis, atopic dermatitis, allergic rhinitis or allergic asthma in a large patient cohort.Thus, irritant control testing with SLS, which is useful in interpreting doubtful allergen patch test results, does not depend on individual atopy status. Linked Comment: Agner and Elsner. Br J Dermatol 2020; 183:13. Plain language summary available online Respond to this article [ABSTRACT FROM AUTHOR]

To quantify the independent impact of potential risk factors for nickel contact allergy (NCA), a multifactorial Poisson regression analysis of standardized anamnestic and patch test data (with nickel sulfate, 5% in petrolatum) was performed, comprising 74 940 patients assessed in the 33 German and Austrian contact dermatitis units of the Information Network of Departments of Dermatology (IVDK) between 1992 and 2000. NCA was observed in 15.5% patients. Female sex was the strongest risk factor (prevalence ratio 3.74, 95% CI: 3.51–3.98). Risk increased monotonically and significantly with decreasing age. Atopic dermatitis was not a risk factor. The year of patch test had no influence on NCA risk. Significant variation of risk between occupations was observed. In conclusion, our multifactorial analysis was able to quantify the impact of established risk factors and additionally address other, e.g. occupational, factors yet unidentified. [ABSTRACT FROM AUTHOR]

Background: Concerns regarding contact allergies and intolerance reactions to dental materials are widespread among patients. Development of novel dental materials and less frequent amalgam use may alter sensitization profiles in patients with possible contact allergy., Objectives: To analyse current sensitization patterns to dental materials in patients with suspected contact allergy., Methods: This retrospective, multicentre analysis from the Information Network of Departments of Dermatology (IVDK) selected participants from 169 834 people tested in 2005-2019 and registered with (i) an affected area of 'mouth' (and 'lips'/'perioral'), (ii) with the dental material in question belonging to one of three groups (dental filling materials, oral implants or dentures or equivalents) and (iii) with patch-testing done in parallel with the German baseline series, (dental) metal series and dental technician series., Results: A total of 2730 of 169 834 tested patients met the inclusion criteria. The patients were predominantly women (81.2%) aged ≥ 40 years (92.8%). The sensitization rates with confirmed allergic contact stomatitis in women (n = 444) were highest for metals (nickel 28.6%, palladium 21.4%, amalgam 10.9%), (meth)acrylates [2-hydroxyethyl methacrylate (HEMA) 4.8%] and the substances propolis (6.8%) and 'balsam of Peru' (11.4%). The most relevant acrylates were HEMA, 2-hydroxypropyl methacrylate, methyl methacrylate, ethylene glycol dimethacrylate and pentaerythritol triacrylate. Few men were diagnosed with allergic contact stomatitis (n = 68); sensitization rates in men were highest for propolis (14.9%) and amalgam (13.6%)., Conclusions: Allergic contact stomatitis to dental materials is rare. Patch testing should not only focus on metals such as nickel, palladium, amalgam and gold, but also (meth)acrylates and the natural substances propolis and 'balsam of Peru'., Competing Interests: Conflicts of interest The authors declare no conflicts of interest., (© The Author(s) 2023. Published by Oxford University Press on behalf of British Association of Dermatologists. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Introduction: Painters and varnishers ("painters") are exposed to various contact allergens and skin irritants, and therefore, are at risk for developing occupational dermatitis (OD)., Objective: To describe the spectrum of occupational sensitizations in painters and revise the corresponding current patch test recommendations., Patients and Methods: Retrospective analysis of Information Network of Departments of Dermatology (IVDK) data from 2000 to 2019 with focus on male painters with OD, ages 20-59 years (n = 557) in comparison to age-matched male painters without OD (n = 422) and male OD patients who have had never worked as painters (n = 13 862)., Results: Male painters with OD have a significantly higher rate of allergic contact dermatitis and face dermatitis than male patients with OD who work in other professions. Positive patch tests to epoxy resin, methylisothiazolinone (MI), and methylchloroisothiazolinone (MCI)/MI were significantly more frequent in painters with OD than in the other groups. Epoxy resin sensitization was significantly associated with face dermatitis., Conclusions: Epoxy resin, MI, and MCI/MI represent the most important occupational sensitizers in painters. In addition to baseline, resins and glues, and industrial biocides series, the patients' own workplace materials should be tested in painters with suspected OD., (© 2021 The Authors. Contact Dermatitis published by John Wiley & Sons Ltd.)

Background: Allergic contact dermatitis caused by shoes is common and new relevant allergens have been identified., Objectives: To investigate the pattern of type IV sensitization in patients with suspected allergic contact dermatitis of the feet related to shoes as a presumed culprit trigger., Methods: Retrospective analysis of data of the Information Network of Departments of Dermatology (IVDK), 2009-2018., Results: Six hundred twenty-five patients with presumed shoe dermatitis were identified in a cohort of 119 417 patients. Compared to patients with suspected contact sensitization from other allergen sources (n = 118 792), study group patients were more frequently sensitized to potassium dichromate (10.8% vs 3.5%), colophony (7.2% vs 3.7%), mercaptobenzothiazole (MBT; 4.0% vs 0.6%), mercapto mix (4.6% vs 0.6%), and p-tert-butylphenol formaldehyde resin (1.6% vs 0.5%). Sensitizations to urea formaldehyde resin, melamine formaldehyde resin, glutaraldehyde, tricresyl phosphate, and phenyl glycidylether were rare. Moreover, reactions to compounds in the leather or textile dyes test series were scarce., Conclusion: A distinct sensitization pattern was observed in patients with suspected allergy to shoe materials. Although substances with low sensitization rates should be removed from the leather and shoe patch test series, novel potential allergens should be added., (© 2021 The Authors. Contact Dermatitis published by John Wiley & Sons Ltd.)

Background: The association of atopic dermatitis (AD) and allergic contact dermatitis has been a matter of considerable uncertainty. Study results range from lack of any association to increased sensitization for multiple allergens, but fail to identify consistent allergen associations., Objective: We studied a large patch test cohort of patients stratified by their atopic skin diathesis using the Erlangen Atopy Score (EAS), independent of active skin disease., Methods: Retrospective multi-center data analysis from five departments of dermatology in Germany with 4,509 patients. Patients were grouped as "no atopic skin diathesis" (n = 2,165) and "atopic skin diathesis" (n = 1,743), according to EAS., Results: Significantly more individuals with atopic skin diathesis showed at least one positive patch test reaction to the baseline series compared to individuals without atopic skin diathesis (49.1 % vs. 38.3 %). In logistic regression analyses, atopic skin diathesis was associated with a significantly higher risk of sensitization to methylchloroisothiazolinone/methylisothiazolinone (OR 2.383) and methylisothiazolinone (OR 1.891), thiuram mix (OR 1.614), as well as nickel (OR 1.530), cobalt (OR 1.683), and chromium (OR 2.089)., Conclusions: Atopic skin diathesis proved to be the most important intrinsic risk factor for contact sensitization to few, specific allergens. Past or present AD was a less relevant variable., (© 2021 The Authors. Journal der Deutschen Dermatologischen Gesellschaft published by John Wiley & Sons Ltd on behalf of Deutsche Dermatologische Gesellschaft.)

Background: Sensitization rates to aeroallergens are rising worldwide. The prevalence is increasing, especially in Western countries. We aimed to investigate (1) sensitization rates and (2) cross-sensitization patterns in skin prick tests (SPTs) for the most relevant inhaled allergens in central Germany over 20 years, adjusted for regional pollen counts., Patients and Methods: This monocentric study evaluated SPTs for tree pollen, grass pollen and house dust mites (HDMs) in 4,315 patients (including children) with suspected airway allergies, from 1998-2017., Results: Sensitization rates to almost all aeroallergens have increased significantly over time, without relevant changes in regional pollen counts. Current sensitization rates in all our symptomatic patients were highest for grass (55.3 %) and rye pollen (59.6 %), with most pronounced increases in HDM sensitization over time (from 37.8 % to the current figure of 50.1 %). However, a low but consistent proportion of tree-sensitized patients (3.6-7.8 %) showed isolated positive SPTs to alder and/or hazel pollen without sensitization to birch pollen., Conclusions: We demonstrate a significant rise in the total number of sensitized patients as well as increases in cross-sensitization between closely related allergens. Individuals with unusual mono-sensitization profiles to common inhaled allergens should be studied in more detail, since these patients are currently excluded from clinical trials for allergen immunotherapy., (© 2020 The Authors. Journal der Deutschen Dermatologischen Gesellschaft published by John Wiley & Sons Ltd on behalf of Deutsche Dermatologische Gesellschaft.)

Background: Fungal spores are ubiquitous allergens. Severe forms of asthma are particularly highly associated with fungal sensitization. National and international asthma guidelines recommend the implementation of allergen immunotherapy if indicated. Thus, detection and treatment of relevant allergies are key components of primary care of these patients., Objectives: The aims of the study were (i) to investigate trends in the prevalence of sensitization to twelve fungi in central Germany over the last 20 years and (ii) to dissect specific sensitization patterns among the 3 most important fungi: Aspergillus, Alternaria, and Cladosporium., Methods: This single-center study evaluated skin prick test (SPT) results of 3,358 patients with suspected airway allergies over a period of 20 years (1998-2017)., Results: While 19.2% of all study patients had positive test results to at least 1 of the 3 fungi (Alternaria, Aspergillus, or Cladosporium) in the first study decade, this rate increased to 22.5% in the second decade. Slight increases in sensitization rates to almost all fungi were observed over the 20-year period. In the last decade, polysensitization to Alternaria, Aspergillus, and Cladosporium increased significantly. Sensitization to fungi is age-dependent and peaks in the age-group of 21-40 years during the second decade., Conclusion: Fungi are relevant allergens for perennial and seasonal allergy symptoms. We currently recommend including Aspergillus, Alternaria, and Cladosporium in the standard series of SPTs for airway allergies., (© 2021 The Author(s). Published by S. Karger AG, Basel.)

Background: Metalworkers are exposed to a variety of contact allergens by handling tools, metals, metalworking fluids (MWFs), oils and greases, rubber materials, and so on. Most large-scale reports on contact allergy due to MWFs are more than 10-years-old, and there are only few studies on contact allergy in mechanics and other metal workers not exposed to MWFs., Objectives: To describe a current spectrum of contact sensitization in metalworkers with occupational dermatitis (OD)., Patients and Methods: Retrospective analysis of patch test data collected by the Information Network of Departments of Dermatology (IVDK; 2010-2018), stratifying for 804 cutting metalworkers, 2197 mechanics, and 355 other metalworkers., Results: Cutting metalworkers were most frequently sensitized to monoethanolamine (12.6%), colophonium/abietic acid (11.4%) and formaldehyde releasers (up to 8.5%) from the MWF series, and formaldehyde (4.6%) and iodopropynyl butylcarbamate (4.6%) from the baseline series. Sensitization among mechanics and other metalworkers indicates possible occupational exposure to MWFs, glues, and resins, although this may not be expected from their job titles., Conclusions: The spectrum of MWF contact allergens remained largely unchanged during the last years. Taking a comprehensive occupational history is indispensable in order to not miss relevant allergen exposures., (© 2020 The Authors. Contact Dermatitis published by John Wiley & Sons Ltd.)

Background: In Germany, a multistep approach has been established to prevent work-related skin diseases (WRSDs)., Objectives: To evaluate the effect of a secondary individual prevention program (SIP) in metalworkers with WRSD and to compare their characteristics with those of participants of a tertiary individual prevention program (TIP)., Patients and Methods: In a prospective cohort study, metalworkers with WRSD of the hands participating either in the SIP (n = 114) or in the TIP (n = 83) were recruited. At baseline and at the respective follow-up 8-12 weeks after the SIP or at dismissal from the TIP (3-4 weeks later), questionnaires were completed and the severity of WRSD was assessed. Saliva samples were collected for assessment of filaggrin (FLG) mutations and an explorative genome-wide association study (GWAS)., Results: Ninety-three SIP patients (81.6%) attended the follow-up. Disease severity was significantly reduced, and knowledge and protective behavior were significantly improved compared to baseline. Significant differences between SIP and TIP patients were found regarding duration and severity of symptoms, work absenteeism, tobacco smoking, and presence of atopic dermatitis, but not regarding FLG mutations and by GWAS., Conclusions: The SIP was effective in metalworkers with WRSDs. Individual factors may influence the course of the disease and the need for the TIP., (© 2020 The Authors. Contact Dermatitis published by John Wiley & Sons Ltd.)

Background: Metalworkers occupationally exposed to metals, tools, metalworking fluids (MWFs), technical oils, gloves, skin care products etc. frequently suffer from occupational dermatitis (OD)., Objectives: To investigate occupational exposure and to identify relevant occupational sensitizers in metalworkers with OD, and to evaluate suitability of current German patch test recommendations for this occupational group., Patients and Methods: As part of the OCCUDERM project, occupational exposure of 230 metalworkers with suspected OD patch tested in the departments of dermatology in Göttingen and Osnabrück (both Lower Saxony, Germany) in 2012-2017 was recorded by questionnaire. These data, as well as results, of patch testing with standardized allergens and with workplace material were analysed., Results: Metalworking fluids and skin care products were the most important exposures. Among MWF allergens, most frequently sensitizations to formaldehyde and formaldehyde releasers, colophony/abietic acid and monoethanolamine were observed. Sensitization to methylisothiazolinone (MI) was frequent, probably as part of the general European epidemic of contact allergy to MI in leave-on cosmetics. Sensitization to glove ingredients only played a minor role., Conclusions: The known occupational allergen spectrum could largely be confirmed. In order not to miss relevant sensitizations, patch testing with material from the patients' workplaces in parallel to baseline and MWF series is recommended. Sensitizations diagnosed could not always be linked to particular occupational exposures., (© 2019 European Academy of Dermatology and Venereology.)

Background: In contrast to the 3 major aeroallergens tree pollen, grass pollen, and house dust mites, allergic rhinitis caused by herbal pollen has received comparatively little attention in recent clinical studies. Since various weeds flower during summer until fall, allergic rhinitis to weeds may be underdiagnosed and/or mistakenly diagnosed as grass pollen allergy., Objective: To investigate (i) the currently most frequent weed allergy between mugwort, ragweed, plantain, chamomile, nettle, and oilseed rape and (ii) time trends in prevalence of sensitization to weed pollen in the middle of Germany over the last 20 years., Methods: This study, the largest of its kind to date, monocentrically evaluated the prick test results of a total of 6,220 patients with suspected RCA over a period of 20 years (1998-2017)., Results: In the study cohort, sensitization rates to plantain almost doubled from 26.6% in the decade 1998-2007 to 50.5% in 2008-2017. Identical increases were observed for ragweed, while sensitization rates for mugwort stayed largely unchanged. The most prominent increase in positive skin prick tests to plantain and ragweed pollen was mainly observed in younger patients. Further, we identified a trend toward polysensitization, currently dominated by plantain and ragweed. Sensitization to weed pollen was found to be highly associated with additional sensitizations to grass and/or birch pollen., Conclusion: Plantain is currently the best choice to screen rhinitis patients for weed allergy which identifies 86% of all weed-sensitized individuals, at least in Germany. Over the last 20 years, we demonstrate a significant rise in the total number of weed pollen sensitization as well as increases in polysensitization, predominantly in younger patients., (© 2019 S. Karger AG, Basel.)

Background: Contact urticaria (CU) is an infrequent, mostly occupational disease that may be life-threatening (CU syndrome stage 4)., Objectives: To identify the current frequency, elicitors and cofactors of CU., Patients: Three cohorts were retrospectively analysed for CU: (a) patients from the Information Network of Departments of Dermatology (IVDK) database (2000-2014; n = 159 947); (b) patients from an allergy unit (Department of Dermatology, University Hospital Erlangen, 2000-2015; n = 4741); and (c) patients from the Anaphylaxis Registry (2007-2015: 6365 reported cases, including 2473 patients with Ring and Messmer grade III-IV reactions) for severe cases with skin/mucosal manifestations occurring at the workplace vs cases not occurring at the workplace (n = 68 vs n = 1821)., Results: Four hundred and forty-eight CU patients (0.28%) were diagnosed in the IVDK cohort, and 16 (0.34%) (10 of immunological aetiology, and 6 of non-immunological aetiology) in the Erlangen cohort. The most frequent elicitors in the IVDK cohort were cosmetics, creams, sun protection agents (although these were less frequent in CU patients than in controls without CU; 26.8% vs 35.6%, P < .0001), and gloves (significantly more frequent in CU patients than in controls; 18.1% vs 6.5%, P < .0001). The most frequent elicitors in the Erlangen cohort were natural rubber latex and sorbic acid. Among the MOAHLFA index characteristics, in both cohorts occupational disease was more common in CU patients than in patients without CU. CU was significantly associated with allergic rhinitis and allergic asthma. Wet work was a relevant cofactor. In the Anaphylaxis Registry, 19 cases (0.3%) were identified with severe reactions including skin symptoms at the workplace linked to common occupational elicitors., Conclusions: CU is a rare occupational skin manifestation with a frequency of <0.4% in the examined patients; it may, however, progress to anaphylaxis. Preventive measures are important, and should take into account the identified elicitors and cofactors., (© 2019 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: Contact sensitization in children is increasing. The offending allergens differ depending on patient age and sex. We aimed to determine the sensitization profiles in children (aged 6-12) and adolescents (aged 13-18), to compare these to a control group of adults (aged 60-66), and to evaluate differences in sensitization patterns between working and non-working adolescents., Patients/materials/methods: We analyzed Information Network of Departments of Dermatology (IVDK) data from 2009 to 2016 using multiple logistic regression analysis. Of the 99 082 patients documented in the IVDK database, 591 children, 2451 adolescents and 12 122 adults were included in further analysis., Results: Nickel was the most frequent contact allergen among all age-groups. Children and adolescents showed significantly lower reaction rates to fragrance mix, methyldibromo-glutaronitrile, methylisothiazolinone, and propolis than adults. Positive reactions to sorbitan sesquioleate and mercapto mix among children and to cobalt among adolescents were significantly more frequent than in adults. Working adolescents had more often positive reactions to methyl(chloro)isothiazolinone (skin lesions predominantly on hands) and paraben mix (skin lesions predominantly on feet) when compared to non-working peers. Patch-tested children were more often diagnosed with atopic dermatitis than adults (P < 0.0001)., Conclusions: Contact allergens display age-specific patterns, which should be considered in a standardized series targeting different patient populations (children and adolescents). Employed adolescents should preferably be tested with the baseline series to optimize allergen identification., (© 2019 EAACI and John Wiley and Sons A/S. Published by John Wiley and Sons Ltd.)

Background: Professional musicians have prolonged and intense physical contact with their instruments. This can lead to occupational skin diseases, particularly irritant and allergic contact dermatitis., Objectives: To assess the skin diseases and sensitization patterns common among professional musicians., Methods: A retrospective analysis of the data of the Information Network of Departments of Dermatology (IVDK) was performed, including data from 1997 to 2017., Results: We identified 236 professional musicians. In this group, male sex (58.6%) and younger age (60.6% aged < 40 years) were common. The musicians suffered more frequently from facial dermatitis (23.7% vs 15.7%) and less often from leg dermatitis (5.1% vs 10.7%) than the control group (the non-musicians in the IVDK database). The most frequent diagnoses were allergic contact dermatitis, atopic dermatitis, and irritant contact dermatitis. The sensitization profile of the professional musicians was similar to that of the control group. In 8.9% of cases, an occupational background of skin disease was confirmed., Conclusions: Severe occupational skin diseases among professional musicians are not as common as in classic "skin-damaging" professions. However, as these skin conditions can mostly be controlled with simple preventive measures, we recommend that this group should be patch tested and treated by a specialist., (© 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: Earlier studies suggested an inverse association between contact allergy and psoriasis, although the results of clinical studies have been inconsistent. Gene expression studies in human contact allergy focusing on immune responses revealed nickel being an inducer of T helper (Th)1/Th17 and some Th22 immune polarization, whereas fragrances were found to promote a Th2-dominated immune activation., Objectives: To investigate the epidemiological association between contact allergy and psoriasis in a large multicentre cohort and to analyse the sensitization profile to specific allergens in these patients., Methods: Retrospective analysis of patch-tested patients from 56 departments of dermatology (1996-2015), including 2387 patients with psoriasis and 161 989 control patients. All patients with atopic dermatitis were excluded from both groups., Results: The odds ratio (OR) for contact allergy was calculated to be 0·55 in patients with psoriasis (95% confidence interval 0·50-0·59). Logistic regression analyses with several independent variables indicated a 'protective effect' of having psoriasis for most allergens, independently of age, sex, affected body site and patch test indication. Fragrance mix II (OR 0·36) and lanolin alcohols (OR 0·38) were found to be among the least common allergens in patients with psoriasis. In contrast, the frequency of contact dermatitis to nickel was only marginally affected in patients with psoriasis compared with controls (OR 0·75)., Conclusions: The inverse association between psoriasis and allergic contact sensitization is likely to be not exclusively mediated by psoriasis itself. The polarization of the activated immune response by specific allergens may influence the occurrence and significance of contact allergies in underlying immune-mediated diseases, eventually even beyond the skin., (© 2018 British Association of Dermatologists.)

Background: Allergic contact dermatitis (ACD) is one of the most common occupational skin diseases (OSDs). Its prevalence and the causative allergens differ between occupations., Objectives: To evaluate the prevalence of ACD and the pattern of patch test results of patients taking part in a tertiary individual prevention programme (TIP) for OSD in Germany., Patients and Methods: In a retrospective cohort study, the data of 3411 TIP patients patch tested between 2007 and 2016 were analysed., Results: In 2687 (78.8%) patients, work-related skin disease was diagnosed, mostly hand dermatitis. The highest proportion of face dermatitis was seen in painters (8.1%). ACD was most common in painters (56.8%), hairdressers (45.8%), construction workers (31.5%), gardeners/florists (26.7%), and metalworkers (26.5%). On average, hairdressers had the youngest age (31.4 ± 12.6 years, P < 0.0001) and the shortest time in the profession prior to the TIP (mean 13.7 years). The pattern of patch test reactivity showed occupation-specific differences related to work exposures., Conclusions: Identification of occupational groups at risk for ACD and relevant allergens may help in the development and implementation of targeted prevention strategies. Our data suggest that there should be a particular focus on hairdressers and painters., (© 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Intolerance reactions to metal implants may be caused by metal allergy. However, prior to implantation, 'prophetic'/prophylactic patch testing should not be performed. Pre-implant patch testing should only be done to verify or exclude metal allergy in patients with a corresponding history. In case of implant-related complications - in particular following replacement arthroplasty - such as pain, effusion, skin lesions, reduced range of motion or implant loosening, orthopedic causes should be ruled out first. Workup of suspected metal implant allergy should then be done using the DKG standard series, which includes nickel, cobalt, and chromium preparations. Various studies assessing the usefulness of metal alloy discs for patch testing have shown this particular approach to be ineffective with respect to providing reliable information on metal allergy. Any positive reaction in such tests cannot be assigned to a specific metal contained within the alloy. Furthermore, there is a risk of broad and indiscriminate use of these readily available discs. Accordingly, given the lack of additional benefit compared to patch testing with standardized metal salt preparations, we do not recommend patch testing with metal alloy discs., (© 2015 Deutsche Dermatologische Gesellschaft (DDG). Published by John Wiley & Sons Ltd.)

Background: Airborne contact dermatitis (AirbCD) is not uncommon, according to a large number of published case reports and review articles. Epidemiological data on AirbCD based on larger clinical samples have not yet been published., Objectives: To investigate demographic characteristics and patch test reactivity in patients diagnosed with both occupational and non-occupational AirbCD., Methods: A retrospective analysis of data from the Information Network of Departments of Dermatology (IVDK), 1994-2013, including 201 344 consecutively patch tested patients, was performed., Results: One thousand two hundred and three patients (0.6%) were diagnosed with AirbCD, 421 (35.0%) of these with an occupational background. Occupational dermatitis and face involvement were more prevalent than in patients without AirbCD (n = 200 141). Sensitization to epoxy resin and sensitization to methylchloroisothiazolinone (MCI)/methylisothiazolinone (MI) were significantly associated with AirbCD, and there was a trend for sensitization to Compositae mix and/or sesquiterpene lactone mix to be associated with AirbCD. Adhesives, plastics, construction materials, paints and varnishes in occupational cases, and plants in non-occupational cases, were the most commonly documented culprit product categories., Conclusions: AirbCD is more common in patients with occupational dermatitis than in patients with non-occupational dermatitis. In our clinical sample, components of epoxy resin systems, MCI/MI and Compositae allergens were the most important contact allergens associated with AirbCD. Patch testing with additional allergens is important., (© 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Allergic contact eczema in children is frequent. If clinically suspected, a patch test should be performed. In the present study, data obtained from 116,742 patients who had undergone a patch test from 2005-2014 were analysed. The children group (range 0-12 years) included 925 patients. If at least 700 tested individuals were considered, the most frequent sensitizations in this group were nickel sulfate (8.5 %), fragrance mix I (5.5 %), and colophony (3.4 %), whereby sensitisation in adults was higher for nickel sulfate (15.5 %) and fragrance mix 1 (8.4 %), while being similar for colophony (3.7 %). In adolescents with and without a profession, nickel sulfate (11.1 and 13.6 %, respectively) and cobalt (II) chloride (3.9 and 3.4 %, respectively) were the most frequent positively tested contact allergens. Sensitisations toward fragrance mix I was low (3.9 and 3.4 %, respectively) in comparison to the adult group (8.4 %). In both children and adolescents, toluene diamine and paraphenylenediamine sensitizations were not infrequent, but it must be considered that these allergens were only tested if suspected. The data show that the sensitisation profile among children and adolescents display patterns similar to those in adults. Sensitisations in childhood and adolescence towards dyes like paraphenylendiamine may be associated with increased use of tattooing in these groups.

Background: In Germany, occupational skin diseases rank first in the occupational skin disease statistics for many years. Especially, occupationally acquired contact allergies as well as multi-sensitization are the most important predictors for a poor prognosis and persistent eczema., Objectives: To update the spectrum and sensitization frequencies of most frequent allergens from the standard series in Germany in patients with occupationally acquired type IV sensitizations in general and within different occupational groups., Methods: Data of all employed patients (age range: 16-68 years, n = 14234) patch tested between 2003 and 2013 in the German Departments of the Information Network of Departments of Dermatology (IVDK) and diagnosed occupationally acquired contact dermatitis after patch testing were analyzed. The control group was composed of all other patients (n = 31706) within the same time frame, in which occupationally acquired allergic contact dermatitis was negated explicitly., Results: The prevalence Ratio (PR; indicating risk) was significantly increased for: Thiuram-mix (PR 5.63 95 %CI 4.97-6.4), zinkdiethyldithiocarbamate (PR 6.22 95 %CI 4.76-8.22), mercaptobenzothiazole (MBT) (PR 3.88 95 %CI 3.09-4.89), mercapto-mix without MBT (PR 3.23 95 %CI 2.59-4.03), N-isopropyl-N'-phenyl-p-phenylene diamine (IPPD) (PR 2.3195 %CI 1.87-2.86), epoxy resin (PR 2.82 95 %CI 2.45-3.25), chloromethylisothiazolinone/methylisothiazolinone (MCI/MI) (PR 2.19 95 %CI 1.97-2.42) and compositae mix II (PR 2.05 95 %CI 1.45-2.89). They were the predominant occupational allergens and were at least associated with a doubled risk (PR ≥ 2.0) for acquiring occupationally allergic contact dermatitis. The highest risk increase was identified in employees in the health services, in agriculture, metal industry, food and service industry as well as building trades, Conclusions: A limited number of occupationally relevant allergens cause the majority of sensitizations in the workforce, if standard series allergens are concerned. Data analysis of national and international contact allergy data bases provide valuable information on sensitization rates and profiles in skin risk occupations to implement targeted prevention strategies. To diagnose occupational allergic contact dermatitis in individual cases additional testing of occupation related patch test series as well as patients' own products is commonly inevitable.

Background: Allergic contact dermatitis caused by (meth)acrylates used in artificial nails is a relevant problem in both nail artists and consumers., Objective: To analyse the frequency of this problem in the contact allergy surveillance network Information Network of Departments of Dermatology in 2004-2013, and address possible time trends and patterns of co-sensitization., Methods: A retrospective analysis of patch test results with (meth)acrylates, along with clinical and demographic data, was performed. These were used to subdivide patients according to (i) a potentially exposed occupation and (ii) nail cosmetics as the suspected cause of contact dermatitis., Results: Among the 114 440 patients patch tested, 72 244 were female and were considered further. Eighty-seven patients both worked as nail artists/cosmetologists and suspected nail cosmetics as the cause of dermatitis. Among these, 47.1% reacted to at least one (meth)acrylate, most often to 2-hydroxyethyl methacrylate (n = 27), 2-hydroxypropyl methacrylate, and hydroxyethyl acrylate (n = 26 each), with marked coupled reactivity. In other subgroups of interest, frequencies of sensitization to (meth)acrylates were less elevated but higher than in all remaining female patients (n = 69 419)., Conclusions: The results indicate a not entirely common, but potentially serious, problem, especially concerning occupationally exposed, and sensitized, nail artists. Adequate protective measures should be taught as part of the vocational training., (© 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: Healthcare workers are occupationally exposed to various allergens in protective gloves, surface or instrument disinfectants, drugs, and skin care products. An increased prevalence of sensitization to thiurams, glutaraldehyde, formaldehyde and glyoxal in nurses with occupational contact dermatitis (OCD) has been known since the 1990s., Objectives: To update the range of occupational allergens in healthcare professionals., Methods: We retrospectively analysed patch test data from the Information Network of Departments of Dermatology (IVDK), 2003-2012. Patch test results from 2248 nurses with OCD were compared with those of 2138 nurses without OCD., Results: Significantly increased sensitization rates were found for thiuram mix (6.7%), potassium dichromate (5.7%), methylchloroisothiazolinone/methylisothiazolinone (4.4%), colophonium (3.4%), 2-bromo-2-nitropropane-1,3-diol (1.7%), and zinc diethyldithiocarbamate (1.7%). Patch testing with products from the patients' workplaces gave additional clues to further allergens, for example tetrazepam., Conclusions: The known range of contact sensitization in nurses with OCD has been confirmed. Formaldehyde allergy seems to be less important today. Drugs such as tetrazepam are occupational sensitizers in nurses. The increase in chromium sensitization remains unexplained., (© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

In clinical practice occupational skin diseases usually present as hand dermatitis. Occupationally acquired contact allergies are of eminent relevance in many work place products e.g. skin care products, dyes and paints, epoxy resins or protective gloves. However, not infrequently, a range of other dermatoses of different etiology and localization can be occupationally induced and, at least in Germany, thus be medically treated and--if necessary--compensated for with full coverage by the statutory employers' liability insurance. Examples regarding non-eczematous skin diseases triggered by external factors are psoriatic lesions, cutaneous type-1-allergies, occupationally acquired infections, and dermatoses in other localizations which are occupationally exposed to irritant influences (e.g. feet in workers wearing occlusive safety boots). Moreover, outdoor workers deserve specific attention by the dermatologist if squamous cell carcinomas including precursor lesions like actinic keratoses or Bowen disease have occurred. In Germany, recently the scientific advisory committee to the Ministry of Labor has recommended including these skin cancers caused by occupational solar UV exposure in the national list of occupational diseases. The framework for dermatological preventive care of occupationally-induced inflammatory dermatoses has been continuously improved in the last years. The aim is to reach a similar level of care and preventive measures for patients with occupational skin cancer, including primary preventive workers' education.

Background and Objectives: The relevance of contact allergens is subject to constant change due to changing exposures according to consumers' preferences and legal requirements. The objective of this paper is to present trends in contact sensitization from the DKG and IVDK patch test clinics, which have led to changes in the DKG standard series (as of 1.1.2014), as well as the current legal framework which has influenced these trends and the way patch testing is performed., Patients and Methods: The patients from 56 DKG and IVDK patch test clinics from 2010 (n = 13,117), 2011 (n = 13,320) and 2012 (n = 12,529) were analyzed with regard to frequencies of sensitization (hit list) to contact allergens as well as the location of allergic contact dermatitis., Results: With a sensitization rate of 15 % nickel is still the most frequently recognized contact allergen. An increase can be observed for fragrance mix I (9.1 %), the preservative composition of methylchloroisothiazolinone/methylisothiazolinone (MCI/MI) (4.5 %) and methylisothiazolinone (MI) alone (6.8 %). A decline is present for potassium dichromate from above 6 % (2007) to 3 % (2012) and for bufexamac (currently at 0.6 %). Backgrounds, legal requirements and resulting changes to the DKG standard series are illustrated., Conclusions: The indicated trends demonstrate the relevance of clinical epidemiology and the "sentinel function" of DKG and IVDK with regard to public health and prevention of contact allergies., (© 2014 Deutsche Dermatologische Gesellschaft (DDG). Published by John Wiley & Sons Ltd.)

Background: Being a contact allergen of general relevance, p-phenylenediamine (PPD) is patch tested in the baseline series. However, PPD 1% in petrolatum may actively sensitize. Patch testing with PPD at 0.35% pet. proved to be safe, as far as active sensitization is concerned., Objectives: To determine whether PPD 0.3% pet. reliably detects PPD sensitization., Methods: Patch testing with PPD 0.3% pet. and 1% pet. synchronously was performed in consecutive patients in a multicentre study within the Information Network of Departments of Dermatology., Results: Altogether, 2042 patients were patch tested. PPD 1% pet. yielded 6.0% positive reactions (n = 123), and PPD 0.3% pet. yielded 4.7% (n = 95). The synchronous reproducibility of PPD reactions was similar as known from parallel patch tests with identical PPD concentrations. The diagnostic properties of PPD 0.3% pet. expressed as reaction index and positivity ratio were good. Of the 123 patients reacting to PPD 1% pet., 32 (26%) had no positive reaction to PPD 0.3% pet. In 22 of these 32 patients (69%), no clinical relevance could be found., Conclusions: As patch testing with PPD 0.3% pet. is reliable according to our results, we recommend replacing PPD 1% pet. in the baseline series with PPD 0.3% pet., (© 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: The frequency of sensitization to methylchloroisothiazolinone (MCI)/ methylisothiazolinone (MI) observed in the Information Network of Departments of Dermatology (IVDK) was constantly around 2.1% from 1998 to 2009. After that, it increased to 3.9% in 2011, paralleled by an increase in the frequency of allergic reactions to MI in the preservative series from 1.9% in 2009 to 4.4% in 2011. MI without MCI has increasingly been used as a preservative in cosmetics and skin care products in recent years., Objectives: To epidemiologically investigate the possible reasons for this development and to analyse concomitant reactions to MCI/MI and MI., Methods: A retrospective analysis of IVDK data from 2009 to 2011 was performed., Results: Stratified data analysis revealed pronounced increases in reactivity to MCI/MI and MI in females, face dermatitis patients, and patients tested because of suspected cosmetic intolerance. The proportion of MI-positive patients among those reacting to MCI/MI increased from 43% to 59% between 2009 and 2011., Conclusion: More widespread consumer exposure has most likely led to the increase in primary sensitization to MI and subsequently to a rise in MCI/MI reactions resulting from immunological cross-reactions. A reduction in the maximum use concentration of MI seems advisable. MI should be patch tested in the baseline series., (© 2012 John Wiley & Sons A/S.)

Background: The preservative methylchloroisothiazolinone (MCI)/methylisothiazo- linone (MI) is an important allergen, and has thus been subject to regulation in some areas of exposure, mainly in cosmetics., Objectives: To examine whether a decline in sensitization prevalence and intensity of elicitation (by the patch test) can be observed, either overall, or in certain subgroups defined by causative exposures., Methods: On the basis of long-term contact allergy surveillance data collected by the Information Network of Departments of Dermatology (www.ivkd.org), 1992-2010, in the course of 171 883 consultations, the time trend of (different grades of) positive patch test reactions to MCI/MI (0.01% aqua) was examined in an age-stratified analysis., Results: The overall frequency of positive patch test reactions was 2.33% (95% confidence interval 2.26-2.4%). No significant overall trend of positive reactions or of the distribution of +, ++ and + + + reactions (p > 0.05) was observed, similarly to what was found for patients in whom cosmetics were recorded as causative exposure (p = 0.55). In contrast, in patients with occupational contact dermatitis who were < 40 years of age, a significant increase in prevalence, by 0.87 percentage points per decade, was identified (p = 0.018)., Conclusions: Both applications of MCI/MI, cosmetic and industrial, should be the target of further preventive efforts., (© 2012 John Wiley & Sons A/S.)

Contact allergy (CA) surveillance networks provide information to a multitude of stakeholders, which is indispensable for evidence-based decision-making in the field of prevention. Methods and results of the German surveillance system on CA are reviewed and discussed with reference to other systems. The German network structure comprises 56 departments of dermatology and includes all patients who are patch-tested for suspected CA. Data analysis considers the results of patch testing and further pertinent information for each patient. Following aspects are addressed: (i) the description of the clinical population, (ii) evaluation of patch test reactions, (iii) relationship between patch test results and population characteristics. Trend analyses on chromate (decreasing), epoxy resin (increasing) and nickel (heterogeneous) served as examples for surveillance system analyses, with the identification of sentinel events, as well as proof of success or failure of prevention. In addition, external data sources can be used such as sales data of patch test preparations to estimate frequencies of sensitization on a population level. National prescription data of drugs and statistics of labelling of preservatives on cosmetics can be included, the latter two approaches allowing for risk estimates conferred by specific allergens., (© 2012 John Wiley & Sons A/S.)

A total of 56 departments of dermatology from Germany, Austria, and Switzerland collaborate to study the clinical epidemiology of contact allergies (CA). Data generated in the course of the diagnostic work-up of CA (e.g., patch test data) have been stored since 1989 in the data center in Göttingen, Germany, including data for more than 200,000 patients (March 2011). These data can be used as a register and as a surveillance system. Analysis of the register may identify and quantify risk factors of sensitization to an allergen, which is exemplified with the case of the allergen para-phenylenediamine. It turned out that-in addition to the risk factor hair dyeing-other important risk factors must be considered. In contrast, data collected every 6 months (from approximately 6,000 patients) allow for time-trend analyses of allergens, thus, identifying allergens of concern, which is of utmost importance for early preventive intervention. Here, the epidemiology of allergies to epoxy resins serves as an example. Continuous monitoring of contact allergens will also be mandatory in the future, as the CA premarketing screening systems will have imperfect predictive values with regard to human CA risk. Unfortunately, the (current) national regulatory framework severely hampers clinical surveillance/epidemiology of contact sensitization and, thus, prevention of contact allergy.

Background: Adverse reactions to permanent hair dyes are frequent, and primarily result from sensitization to p-phenylenediamine (PPD)., Objectives: To investigate the degree of cross-reactivity to a chemically similar dye, hydroxyethyl-p-phenylenediamine sulfate (HPPS), and whether this might be a dyeing alternative for patients who are sensitive to PPD., Method: HPPS was patch tested in two concentrations in a total of 216 patients suspected of having contact dermatitis caused by hair dyes and/or hair cosmetics. A regular use test with a hair dye containing HPPS was suggested to every patient who had had an adverse reaction to a PPD hair dye in the past., Results: Forty of 216 (19.9%) patients reacted to 1% PPD, whereas only 2/216 (0.9%) showed a positive reaction to 1% HPPS. Reactivity to 2% HPPS was only slightly higher (5/216, 2.3%). On the basis of the 43 PPD-positive patients, the reactivity to 2% HPPS amounted to 12%; the corresponding figure for toluene-2,5-diamine was 15% (5/33). In a use test on two PPD-positive patients with a hair dye containing HPPS, no adverse reaction was seen, even after several years of regular dyeing. CONCLUSIONS. HPPS may be an alternative hair dye for individuals not tolerating PPD-containing dyes. However, cross-reactivity with PPD and other aromatic amines may occur. HPPS is also a known sensitizer, and the risk of de novo sensitization can only be assessed by a controlled study on a large panel and under regular use conditions., (© 2011 John Wiley & Sons A/S.)

Purpose: Since 1993, assiduous efforts have been made in Germany to lower the incidence of allergic cement dermatitis by reducing the content of hexavalent chromium (Cr VI). Usage of epoxy resin systems has considerably increased in the building trade in the same period. We analysed data of the Information Network of Departments of Dermatology (IVDK) to evaluate the influence of these changing occupational exposures on frequencies of sensitization., Methods: IVDK data of 1,153 men working in the building trade (bricklayers, tile setters etc.) presenting with occupational skin disease in the years 1994-2008 were analysed, taking into consideration not only the year of patch testing, but also beginning and duration of work in the building trade., Results: While contact sensitization to chromate decreased from 43.1 to 29.0%, sensitization to epoxy resin increased from 8.4 to 12.4%. Logistic regression analysis revealed that, compared to those who had already worked before 1994, patients having started to work in building trade after 1999 had a significantly decreased risk of chromate sensitization (odds ratio 0.42) and a significantly increased risk of sensitization to epoxy resin (odds ratio 2.79). Additionally, risk of thiuram sensitization increased with the duration of employment., Conclusion: Our data confirm that reducing Cr VI content of cement is useful in preventing allergic cement eczema, as previously found in Scandinavia. In contrast, the increasing prevalence of contact sensitization to epoxy resin components in the building trade is alarming. Preventive measures, which have already been implemented, have to be enforced.

Background: Nickel contact allergy is still frequent both in patch-tested patients and in the general population. Objectives. To explain this observation by relating clinical epidemiological data with recent chemical analyses of nickel release from costume jewellery., Methods: (i) The trend of nickel allergy was analysed using data registered between January 1994 and December 2009 in the Information Network of Departments of Dermatology. (ii) In 2008, different parts of items of costume jewellery purchased at random on the German market (n = 609) were analysed for nickel release according to EN 1811:1998 + A1:2008 in five official German laboratories of food and non-food INVESTIGATION., Results: (i) Between 1994 and 2009, nickel allergy decreased in men (18-30 years) and in women (1-17 and 18-30 years); however, after 2000, there was no significant decrease in nickel allergy in the women aged 1-17 years. (ii) Of the post-assemblies, 28.0% exceeded the migration limit of ≥0.2 µg/cm(2) per week, and 5% released ≥26.8 µg/cm(2) per week. In articles with direct and prolonged contact with the skin, 12.8% of decorative parts and 17.1% of clasps exceeded the migration limit. If an adjustment factor was applied, according to the above norm, about half of the items otherwise rejected became acceptable., Conclusion: Exposure to nickel-containing products exceeding the (unnecessarily relaxed) permitted limit may explain why nickel contact allergy remains a problem., (© 2011 John Wiley & Sons A/S.)

Background: Contact sensitization to fragrances is common both in clinical and in population samples. The spectrum of allergens is broad and diverse, and to some extent covered by a set of screening agents., Objectives: To examine the current frequency of contact sensitization to fragrance allergens in patients routinely patch tested for suspected allergic contact dermatitis with the baseline series and special series., Patients and Methods: Between 2005 and 2008, 40 709 patients were patch tested in the departments of the Information Network of Departments of Dermatology (http://www.ivdk.org). Results with selected fragrances were analysed., Results: Of all patients tested with the German baseline series, 15.1% reacted positively to fragrance mix (FM) I (6.6% positive), FM II (4.6% positive) or Myroxylon pereirae resin (balsam of Peru, 6.8% positive). Among the single constituents of FM I, Evernia prunastri [oak moss absolute (abs.)] was the leading allergen, and amyl cinnamal the least frequent allergen. Among fragrances not included in FM I or FM II, Evernia furfuracea (tree moss abs.) was the most common allergen., Conclusions: For diagnostic purposes, it is necessary to combine several screening agents. The frequency of contact sensitization differs greatly between single fragrances., (© 2010 John Wiley & Sons A/S.)

Background: The fragrance mix (FM I), established in 1977, detects the majority, but not all cases of contact allergy to fragrances. Based on European research 2002/2003, fragrance mix II (FM II) was developed to supplement FM I. In 2005, the German Contact Dermatitis Research Group (DKG) added FM II to their baseline series., Objectives: To evaluate reactions to FM II and its constituents in routine patch testing., Methods: Retrospective data analysis of the Information Network of Departments of Dermatology (IVDK), 2005-2008, of patch test results with FM II and its constituents., Results: A total of 35 633 patients were patch tested with FM II as part of the DKG baseline series. Of these, 1742 (4.9%) reacted positively. Concomitant reactions to FM I were observed in 41.9% of the patients reacting to FM II. In 367 FM II-positive patients, a full breakdown test of the mix was performed. Of these, 47.7% reacted to hydroxyisohexyl 3-cyclohexene carboxaldehyde, 16.1% to citral, 11.4% to farnesol, 3.8% to hexyl cinnamal, 2.7% to coumarin, and 2.5% to citronellol., Conclusions: FM II is an important screening and diagnostic tool to detect fragrance allergy. Hydroxyisohexyl 3-cyclohexene carboxaldehyde is the most important fragrance allergen in FM II., (© 2010 John Wiley & Sons A/S.)

A broad spectrum of various substances may cause occupational allergic contact dermatitis. Often, it is difficult to identify potentially or truly relevant allergens at the workplace. Therefore, the consulting physician must have a comprehensive knowledge of possible allergens in different occupations to perform specific diagnostics and to initiate efficient secondary prevention by allergen avoidance. In this review, we give some practically relevant general comments on patch testing in occupational dermatitis, followed by a discussion of important occupational allergens in those occupational groups most frequently affected by occupational dermatitis. Finally, recommendations on which allergens should be tested in the respective occupational groups are given or reported from the literature.

Background: Hidden allergen exposure may contribute to persistence and relapse of chromate dermatitis. According to case reports, chromated metal products, such as screws, fittings, etc., may be relevant allergen sources for patients sensitized to chromate., Objectives: To examine concomitant patch test reactivity to potassium dichromate 0.5% petrolatum (pet.) and three different types of chromated metal rings., Patients/methods: Patients with proven or suspected chromate allergy were patch tested with potassium dichromate 0.5% pet. and three different types of chromated metal rings (yellow, olive, and black). Hexavalent chromium Cr(VI) release from the patch tested rings was chemically analysed., Results: Ninety-five patients were tested: 49/95 (52%) reacted to potassium dichromate and 25/95 (26%) reacted to black chromated rings. Reactions to chromated rings exclusively occurred in patients reacting to potassium dichromate. Of 20 patients with a strong reaction to potassium dichromate, 14 reacted to black chromated rings. These were shown to have a high Cr(VI) release. Only two patients reacted to the other chromated rings, which had a very low Cr(VI) release., Conclusions: Handling chromated metal products must be regarded a hazard to chromate-sensitive patients, in particular those with a strong sensitization.

Background: Despite rare simultaneous exposure, concomitant sensitisation to bisphenol A diglycidyl methacrylate (BIS-GMA) and epoxy resin frequently occurs. Immunological cross-reactivity has not been proven by animal experiments so far., Objective: Our objective was to examine cross-reactivity epidemiologically by analysing data of the Information Network of Departments of Dermatology (IVDK)., Patients/methods: From 2001 to 2005, 3,777 patients were patch tested with epoxy resin and BIS-GMA in the IVDK. We retrospectively analysed concomitant reactions to these allergens and to BIS-GMA and selected methacrylates. Additionally, we compared clinical characteristics of patients reacting to both, epoxy resin and BIS-GMA, with those of patients reacting to epoxy resin or BIS-GMA only., Results: 185 patients reacted to epoxy resin, and 40 to BIS-GMA. Of the latter, 34 reacted to epoxy resin. There was no difference concerning exposure between the above-mentioned groups of patients. Concomitant reactions to BIS-GMA and methacrylates hardly ever occurred., Conclusions: Considering the fact that very few patients had been potentially exposed to BIS-GMA and that 85% of those reacting to BIS-GMA also reacted to epoxy resin, we conclude that our data are presumably indicative of immunological cross-reactivity. A verification of this hypothesis by animal experiments would be promising.

Background: Hair cosmetics, in particular hair dyes, bleaches, and permanent wave solutions, contain a number of potential contact allergens. The pattern of exposure to these in hairdressers, clients and home-users may change over time., Patients and Methods: Data on female patients who consulted centers of the Information Network of Departments of Dermatology (IVDK, http://www.ivdk.org) between 01/2003 and 12/2006 was analyzed. Patients were divided into a) hair-dressers, given they worked in this occupation and suffered from occupational skin disease (n = 480),and b) "clients",who never worked as hairdressers, but in whom hair cosmetics were considered a potential cause of contact dermatitis (n = 780)., Results: In hairdressers, the most important allergens were ammonium persulfate (21.7% positive),p-toluenediamine (PTD,19.6% positive),p-phenylenedi-amine (PPD,18.1% positive) and, with decreasing time trend, glyceryl monothioglycolate (2005/2006 still 7.5% positive). Biocides must be regarded as important allergens in hairdressers, namely,(chloro) methylisothiazolinone and methyldibromoglutaronitrile. Clients, who were considerably older on average, had possibly been tested in a more aimed fashion, yielding (strikingly) higher sensitization prevalences to a number of allergens of oxidative hair dyes such as PPD or PTD., Conclusions: The continual analysis of sensitization prevalences in patients patch tested can identify areas needing in-depth research and preventive intervention, such as avoiding the use of certain biocides in shampoo intended for professional use by hairdressers or further reducing the concentrations in oxidative hair dyes.

Although genetic factors probably account for differences in susceptibility to contact allergy, they have not yet been identified, partly due to an insufficient understanding of 'susceptibility'. Regarding polysensitization (PS) as a sign of increased susceptibility, we studied the relationship between PS and sensitization to weak versus strong allergens. Patch test data from 66,835 patients registered by the multicentre project, Information Network of Departments of Dermatology (IVDK) between 1 January 1997 and 31 December 2004, were analysed. The association between the number of sensitization to standard series allergens, and contact allergy to a strong allergen methyldibromoglutaronitrile (MDBGN) and to a weak allergen (paraben mix), was analysed with adjusted logistic regression analysis. In paraben-positive (++/+++) patients, the risk of > or = 2, > or = 3 or > or = 4 additional reactions were significantly increased by a factor of 2.1-4.6 compared to MDBGN-sensitized (++/+++) patients. Varying the basic model, a higher risk of additional positive reactions associated with paraben sensitization was consistently identified. The association between PS and sensitization to weak allergens adds a further characteristic of susceptibility to former findings of the IVDK, where PS was related to an increased risk of induction, elicitation, and cytokine polymorphisms. PS can be regarded as a phenotype to be considered in genetic studies.

Evidence regarding the risk of active sensitization (AS) to p-phenylenediamine (PPD), patch tested 1% in petrolatum, is conflicting. The objective of this study was to evaluate the relative frequency of 'environmental' exposures and skin reactions to products potentially containing PPD in subgroups of patients with versus without newly diagnosed contact allergy (CA) to PPD upon retesting. Patients patch tested twice with PPD between 1996 and 2004 in the Information Network of Departments of Dermatology (IVDK) network were identified and classified into 4 groups, according to the 2 test results with PPD at D3. A self-administered questionnaire was mailed to 171 patients (response 57%). The frequency of exposure to 'henna tattoos', dark hair dyes, or textiles or work as hairdresser did not differ significantly between the groups. A significantly shorter median interval between the 2 patch tests was observed in the group with newly diagnosed PPD CA compared with the other groups (293 versus >700 days). The results of the study add new, if somewhat weak, evidence to the notion that patch testing with PPD may indeed carry some risk of AS, as environmental exposures to PPD were as common in the subgroup of patients with incident CA to PPD as in the remaining patients.

Background: Although many allergens in metalworking fluids (MWF) are identified, there are still some MWF components, which are not sufficiently investigated concerning their sensitizing properties., Objectives: To investigate sensitization to 10 frequently used MWF components, which are not part of the established MWF test series, in metalworkers with suspected occupational dermatitis due to MWF., Patients/methods: Oleyl alcohol, myristyl alcohol, dimethylolurea, 4,4'-methylenebis morpholine, imazalil, 1-amino-2-propanol (monoisopropanolamine; MIPA), 2-amino-2-ethyl-1,3-propanediol (AEPD), 2,5-bis(n-octyldithio)-1,3,4-thiadiazole, zinc alkyl dithiophosphate and dibenzyl disulfide have been patch tested in 144 patients., Results: 7 patients reacted positively to the formaldehyde releaser 4,4'-methylenebis morpholine, and 6 of these patients also reacted to formaldehyde and/or other formaldehyde releasers. 4 patients reacted positively to myristyl alcohol tested at 10% petrolatum (pet.). Additionally, 20 doubtful or irritant reactions occurred. 1 patient each reacted positively to oleyl alcohol, MIPA, and AEPD. None of the other test substances mentioned above elicited any clear-cut positive reaction. Patch testing with well-known MWF allergens showed proportions of positive reactions, which were comparable to those from other studies, e.g. 11% to monoethanolamine, 8% to colophonium and 3%-5% to various preservatives., Conclusions: 4,4'-methylenebis morpholine may be an important MWF allergen, although clinical relevance could not be stated definitely in every case. Myristyl alcohol should not be patch tested at 10% pet., but at a lesser concentration, due to irritant properties.