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The European baseline series was last updated in 2019. This article discusses the reasoning behind a further iteration of the series for 2023.

BACKGROUND Recent trends in the sensitization of construction workers show a decrease in potassium dichromate and an increase in epoxy resin sensitization. OBJECTIVES To present the trends of occupational contact allergy of construction workers in Greece from 2009 to 2018. METHODS We retrospectively reviewed the files of patients with eczema patch tested in our Contact Dermatitis Clinic who were construction workers. RESULTS A total of 191 construction workers initially reported contact dermatitis. Of these, 138 had occupation-relevant allergic contact dermatitis (ACD) or irritant contact dermatitis (ICD). All patients were men. After being patch tested, 98 (71.0%) were diagnosed with ACD and 40 with ICD. Median duration of occupation till onset of ACD was 2 years (interquartile range [IQR] 0.8-7). The hands were the most common location for ACD (73.5%), followed by the trunk (39.8%), the legs (38.8%), and the face (11.2%). Of the patients, 74.6% had lesions affecting multiple body sites. Potassium dichromate (67%) was the most frequent allergen, followed by thiuram mix (37.4%) and cobalt chloride (31.8%). Sensitization to epoxy resins was lower (12.1%). CONCLUSION The sensitization pattern of Greek construction workers does not follow the trends in Central or Northern Europe, rather sharing attributes with less industrialized countries.

Background The common contact allergens may change over time as the environmental exposure changes. Objectives To identify the prevalence rates and changing trends of contact allergens in Taiwan over a 40-year period. Materials & methods The patch testing results of a referral centre from 1978 to 2018 were retrospectively reviewed. The study population was divided into four groups according to 10-year intervals. The prevalence rates of contact sensitization to each agent and the clinical relevance were analysed. For patients with positive reactions to relevant allergens, the occupations and sites of dermatitis were analysed. Results From 1978 to 2018, a total of 4005 patients underwent patch testing. Successively increasing trends of positive reactions to cobalt, fragrance mix I, and para-phenylenediamine (PPD) were found. Methylchloroisothiazolinone/methylisothiazolinone (MCI/MI) was an emerging contact allergen. Hairdressers, cosmetologists, and aromatherapists became the occupations most commonly having positive reactions in the most recent 10 years. In the first two decades, the face and neck were the most commonly affected areas. Later, hands became the most commonly affected sites. Conclusions The prevalence rates of positive reactions to cobalt, fragrance mix I, and PPD increased successively. MCI/MI was an emerging contact allergen of special concern.

Background: Polyaminopropyl biguanide (INCI name) and polyhexamethylene biguanide (PHMB) are polymeric biguanides. PHMB is a broad-spectrum antimicrobial substance used as a preservative in many products. Due to our limited knowledge on PHMB contact allergy frequency and the fact that cases of allergic contact dermatitis to PHMB might be missed, we have included PHMB as a screening allergen since 2016. Objective: To report the prevalence of positive patch-test reactions to PHMB as a screening allergen in patients with suspected allergic contact dermatitis. Methods: A retrospective analysis of 1760 patch tested patients from July 2016 to December 2018 was performed. Polyaminopropyl biguanide 2.0% aqua was included in the extended Malmo baseline series during the study period. Results: Of all patients, 1204 (68.4%) were female. Positive patch-test reactions were reported in 19 patients (1.1%). The most common sites of lesions were face, head, and neck (52.6%). There was a significant correlation between concomitant reactions to PHMB and other cosmetic-related allergens. Conclusion: The prevalence of positive reactions to PHMB was higher than that previously reported. Patch testing with PHMB should be performed in patient with dermatitis who have lesions on the face, head, and neck. (Less)

Background Occupational contact urticaria due to inhalation of legume pest allergens has rarely been described. Objective To determine the cause of an outbreak of airborne contact urticaria, asthma, and anaphylaxis in farmers and agronomists studying the disinsectization of dried peas. Peas were treated with aluminum phosphide (EPA). Methods Extracts prepared from Bruchus lentis and Bruchus pisorum bodies and from healthy legumes, EPA-treated legumes, and infested legumes, were used for in vivo tests (skin prick testing, oral, and specific bronchial challenge for the diagnosis of asthma and anaphylaxis) in affected patients and in five control patients with severe legume hypersensitivity. Open application, patch testing with the most common legume insecticides, molecular analysis, and IgE immunoblotting were undertaken. Results We found positive responses (prick, provocation, immune detection) to parasitic pea extracts and B. pisorum. A 25 kDa band was detected in the western blot of all patients who worked with infested EPA-treated peas. Bands from B. pisorum extract were detected in all patients. No responses to pea allergens were found in any patient, unlike in legume allergy controls. Oral provocation tests were negative. Conclusion B. pisorum is a cause of contact urticaria and may cause occupational hives, anaphylaxis, and asthma. The allergen may enter by inhalation or puncture of setae released by B. pisorum. HIGHLIGHTS : Allergic reactions may be caused by inhaling legume dust or vapors, but occupational allergy after inhalation or contact of legume pest allergens has rarely been described. Bruchus pisorum is an allergenic source that may cause occupational urticaria, anaphylaxis, and asthma. To the best of our knowledge, this is the first report on allergy caused by this invasive species Pea pest proteins may cause IgE-mediated allergy in patients inhaling infested pea particles. Agronomists, cooks, farmers, and grocery workers are occupational populations at risk.

BACKGROUND The application of preparations containing food allergens can cause percutaneous sensitization and provocation. The prevalence of food allergens in children's cosmetics is unknown. OBJECTIVES To analyse the prevalence of food allergens in skincare products marketed for children and their association with marketing claims and product price. METHODS We reviewed 276 skincare product ingredient labels for the presence of milk, eggs, wheat, soy, oats, tree nuts, peanuts, and sesame. RESULTS More than one-third (108; 39.1%) of the products listed at least one allergen. A total of 156 allergens were recorded, of which 65 (41.7%) were almonds, 35 (22.4%) wheat, 24 (15.4%) soy, 16 (10.3%) oats, 13 (8.3%) sesame, 2 (1.3%) milk, and 1 (0.6%) peanuts. Products that claimed to be "natural" or "ecological" were more likely to contain food allergens than those not labelled so (P < .001). The prices were higher for products containing food allergens compared with allergen-free products (P = .028). CONCLUSIONS Food allergens are prevalent in children's cosmetics, especially those that claim to be natural or ecological. The most incorporated food allergens are almonds, wheat, and soy. Products containing food allergens cost more than allergen-free ones.

BACKGROUND Oxidative hair dyes are an important source of chemical exposure and a major risk factor for the development of occupational and non-occupational allergic contact dermatitis (ACD) worldwide. OBJECTIVE To identify the frequency of common allergens associated with occupational and non-occupational ACD to hair dyes during the last 10 years, in Greece. METHODS We retrospectively reviewed the medical records of patients with suspected ACD to hair dyes from 2010-2019. All patients with patch-test-confirmed ACD to hair dyes were evaluated. RESULTS Out of 501 patients with suspected ACD to hair dyes, 362 had at least one positive reaction to hair dye allergens (62.4% were customers and 37.6% were hairdressers). The mean age of customers and hairdressers was 43.8 years and 30.8 years, respectively. Of the customers, 58.9% were exposed to dyes for >10 years and 61% of hairdressers for

Nickel is the most common cutaneous contact allergen in children. Allergic contact dermatitis eruption is typically localized to the skin areas that come into contact with the allergen and usually presents as recurrent eczematous lesions on the sites of direct contact. We report an adolescent patient who had severe edema of the face mimicking angioedema after the application of boiled chickpea water and has been found to have allergic sensitization to nickel and cobalt. We want to emphasize the unusual presentation of allergic contact dermatitis and different sources of nickel exposure contrary to those already known. This article is protected by copyright. All rights reserved.

Background Allergic contact dermatitis caused by glucose sensors has been recently described in diabetics, mostly in adult patients. Isobornyl acrylate and N-N dimethylacrylamide are the potent causative agents. Objectives To describe a child population with contact dermatitis caused by glucose sensors, determine the causative allergen, and assess the prevalence of isobornyl acrylate (IBOA) sensitization. Patients and methods Overall, 12 children with a reaction to medical devices, either glucose sensors or insulin sets, were patch tested with the European baseline series, glues and rubber, (meth) acrylates series, and with piece of the adhesive part of the glucose sensor FreeStyle Libre. Isobornyl acrylate 0.1% pet. was patch tested in 11 patients, and N-N dimethylacrylamide in two. Some patients were tested with adhesive parts of the infusion set. Results Overall, 10 children reacted to the adhesive part of the sensor FreeStyle Libre, and 10 children were sensitized to IBOA. One patient turned out to be negative in all patch tests. Conclusion Allergic contact dermatitis caused by glucose sensors is common in the pediatric diabetic patient population. Like in the adult patient population, IBOA was the culprit allergen, with 83.3% sensitization prevalence in children exhibiting adverse cutaneous reactions caused by FreeStyle Libre.

Background Red tattoos are prone to allergic reactions. The identity of the allergen(s) is mostly unknown. Objectives Chemical analysis of human skin biopsies from chronic allergic reactions in red tattoos to identify culprit pigment(s) and metals. Material and methods One hundred four dermatome biopsies were analyzed by matrix‐assisted laser desorption/ionization tandem mass spectrometry (MALDI‐MS/MS) for identification of commonly used organic pigments. Metal concentrations were assessed by inductively coupled plasma (ICP)‐MS and x‐ray fluorescence (XRF). Fourteen patients had cross‐reactions in other red tattoos. Results In total, the identified pigments were mainly azo Pigment Red (P.R.) 22 (35%), P.R. 210 (24%), P.R. 170 (12%), P.R. 5 (0.9%), P.R. 112 (0.9%), and Pigment Orange (P.O.) 13 (11%). P.R. 122 (0.9%) and Pigment Violet (P.V.) 23 (8%) were also common. P.R. 22, P.R. 170, and P.R. 210 also dominated in patients with cross‐reactions. In 22% of the biopsies, no red pigment was detected. Element analysis indicated the presence of the sensitizers nickel and chromium. Conclusions P.R. 22, P.R. 170, and P.R. 210 were identified as the prevailing pigments behind chronic allergic reactions in red tattoos. The epitope causing the reaction might be a pigment‐degradation product. Metal contamination may derive from different sources, and its role in red tattoo allergy cannot be ascertained., First study on chemical analysis of human skin biopsies from chronic allergic reactions in red tattoos to identify culprit pigment(s) and metals.Pigment Red (P.R.) 22, P.R.170, and P.R.210 were the prevailing pigments behind chronic allergic reactions in red tattoos. The epitope causing the reaction might be a pigment‐degradation product.Metal contamination is very common in any tattoo ink stock product, and its role in red tattoo allergy appears dubious.

BACKGROUND Hair cosmetics such as hair dyes, bleaching, waving, and cleansing products are composed of numerous chemical ingredients. Allergic reactions to these contact allergens, other than p-phenylenediamine, are rarely reported. OBJECTIVES To study the incidence of patch test reactions to hair cosmetic allergens and identify the factors associated with hair cosmetic allergy in Thailand. METHODS We retrospectively reviewed the case records of patients who underwent patch testing from 2009 to 2018. Patients with at least one positive patch test reaction to a potential contact allergen associated with hair cosmetic ingredients were studied. RESULTS Overall, 2842 patients were patch tested. Of the hair cosmetic allergen categories, preservatives had the highest rate of positive reactions, followed by surfactants and hair dyes. Perming agents were less problematic in comparison. The hands, head, and neck were the predominately affected sites of allergic reactions to hair cosmetic ingredients. CONCLUSIONS Preservatives, surfactants, and hair dyes are important contact allergens, whereas perming agents are less likely to cause allergic reactions. Hair cosmetic ingredients are regulated by national agencies, which influences their extent of exposure and rates of contact allergies. Further continuous observation of hair cosmetic allergy is needed to provide the best patient care.

Background: Tree moss (Pseudevernia furfuracea [L.] Zopf.), a lichen growing on conifers, is a frequent fragrance sensitizer. Previous studies have shown two subgroups of tree moss-allergic patients: a group sensitized to common allergens of tree and oak moss (Evernia prunastri), and another group sensitized to colophonium-derived allergens, which may contaminate tree moss extract. Objectives: To report the results of including tree moss extract in the baseline series and discuss the clinical implications. Methods: Tree moss extract was included in the baseline series and sensitized patients were assessed for concomitant allergy to colophonium and oak moss, and the relevance of these reactions was analyzed. Results: Altogether, 22 of 632 patients (3.5%) had positive reactions to tree moss. Eight patients were sensitized to tree moss only (among fragrance allergens) and 75% had relevant reactions to colophonium. Fourteen patients were sensitized to other fragrance allergens as well and 28.5% had relevant colophonium reactions. Conclusions: The prevalence of positive tree moss reactions is high enough to justify its inclusion in the baseline series. If tree moss is not included, patients with positive colophonium reactions should be informed of possible (false) cross-reactivity to tree moss to avoid this labeled fragrance allergen.

Background Opioid-manufacturing facility workers are at risk of developing occupational contact dermatitis. Objectives To describe the causes of occupational allergic contact dermatitis caused by opioids in an opioid-manufacturing facility. Materials and methods A retrospective review was performed of patients assessed at the Occupational Dermatology Clinic in Melbourne, Australia from 2004 to 2017. Results Fifteen workers from an opioid-manufacturing facility were assessed in our clinic over a period of 14 years. Of these, 11 individuals were diagnosed with occupational allergic contact dermatitis caused by opioids, with seven reacting to thebaine, five to morphine, four to norhydroxymorphinone, two to codeine, and two to oripavine. Two people were suspected of having immediate hypersensitivity reactions to opioids, including one who also had allergic contact dermatitis. Two patients were diagnosed with urticaria, aggravated at work. One patient was diagnosed with a non-occupational rash. Conclusions We report a case series of workers with allergic contact dermatitis caused by opioids in a manufacturing facility. With greater awareness, including implementation of an educational programme and improved skin protection, the number of cases declined over time. Interestingly, norhydroxymorphinone had not been reported as an allergen before. Further testing is required to establish optimal patch test concentrations of all opiates.

Although the development of successful vaccines against coronaviruses may be achieved, for some individuals the immune response that they stimulate may prove to be insufficient for effective host defence. The principle that a relatively strong contact allergen will have an enhancing effect on sensitisation to a less potent contact allergen if they are co‐administered, may not at first appear relevant to this issue. However, this augmentation effect is thought to be due to the sharing of common or complementary pathways. Here we consider briefly aspects of the shared and complementary pathways between skin sensitisation induced by exposure to a contact allergen and the immune response to viruses, with particular reference to Covid‐19. This relationship leads us to explore whether this principle, which we name here as ‘cooperative immune augmentation’ may extend to include viral vaccination. We consider evidence that even relatively weak contact allergens, used in vaccines for other purposes, can show enhanced sensitisation, which is in keeping with a cooperative augmentation principle. Finally, we consider how the potent contact allergen diphenylcyclopropenone could be employed safely as an enhancer of vaccine responses. This article is protected by copyright. All rights reserved.

OBJECTIVES: To determine the prevalence of atopic dermatitis (AD) in the general European population and to assess differences in contact allergy and avoidance of products between subjects with AD in lifetime and those who had not. MATERIALS AND METHODS: In five European countries (The Netherlands, Germany, Italy, Portugal and Sweden) a random sample of 12 377 participants, aged 18 to 74 years were interviewed using a standardized questionnaire. Questions were asked about previous atopic dermatitis and avoidance of products because of a skin reaction. A random sample of 3119 participants was patch tested. TRUE Test panel 1, 2 and 3 and investigator-loaded chamber systems were used, testing for a total of 47 allergens, including the individual fragrance allergens of fragrance mix (FM) I and FM II. Reading was performed at day 3. RESULTS: The physician-diagnosed lifetime prevalence of AD was 7.1% (95% CI 6.7-7.6). The age-standardized physician diagnosed life time prevalences of AD stratified per country were: Germany: 9.4% (95% CI 8.5-10.3); The Netherlands: 8.5% (95% CI 7.2-10.1); Sweden: 7.2% (95% CI 6.1-8.4); Italy 4.2% (95% CI 3.3-5.3); Portugal: 3.3% (95% CI 2.6-4.2). The prevalence of contact allergy to at least one allergen was not significantly different between those with AD in lifetime (31.1%) and those without AD (27.8%). Males with AD were significantly more sensitized to allergens of TRUE Test panel 2 (14.9%) than those without AD (6.9%) (P = .026). The prevalence of contact allergy to individual allergens was not significantly different for those with AD and those without, except for p-phenylenediamine in males: AD (4.0%), no AD (0.7%) (P = .023). The prevalence of a positive patch test reaction to the group of preservatives was slightly albeit not significant (P

INTRODUCTION Carvone (l‐carvone), a mint‐tasting flavour often found in toothpaste, is considered a weak contact allergen and the prevalence of positive patch tests to carvone among dermatitis pat ...

Allergic contact dermatitis caused by medical devices for diabetes patients has been increasingly described in the literature in the last few years. This article reviews the cases of allergic contact dermatitis caused by insulin pumps and glucose sensors reported since the 1970s, the culprit allergen(s), the results of patch tests and/or chromatographic analysis, and preventive measures.

Background. Polysensitization, defined as being allergic to three or more haptens from the European baseline series, is considered to reflect increased susceptibility to developing a contact allergy, and is likely to be associated with an impaired quality of life.Objectives. To evaluate the prevalences of polysensitization across Europe and to analyse factors associated with polysensitization.Methods. Patch test data collected by the European Surveillance System on Contact Allergies (ESSCA; www.essca-dc.org) in consecutively patch tested patients from January 2009 to December 2014, comprising 11 countries and 57 departments, were retrospectively analysed.Results. A total of 86 416 patients were available for analysis, showing a standardized prevalence of polysensitization of 7.02%, ranging from 12.7% (Austria) to 4.6% (Italy). Allergen pairs with the strongest association are reported for the total population, for South Europe, and for North/Central Europe. Overall, polysensitized patients showed a higher percentage of extreme (+++) positive patch test reactions than oligosensitized patients. Female sex, occupational dermatitis and age > 40 years were risk factors for polysensitization.Conclusions. The varying prevalences of polysensitization across Europe most likely reflect differences in patient characteristics and referral patterns between departments. Knownrisk factors for polysensitization are confirmed in a European dermatitis population.

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/cm2 ). 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.

There have been reports of allergic contact dermatitis in response to the plastic part of eyewear. Different substances have been identified as the causative allergens: Solvent Orange 60,1 methylisothiazolinone,2 and triethylene glycol bis(−2ethylhexanoate).3 Here we present the first known case of allergic contact dermatitis caused by CI Solvent Yellow 14 (CAS no. 842–07‐9) used in the plastic part of the glasses, in the temple tips.

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. (Less)

Background. Studies have shown that not all positive patch test reactions are reproducible upon retesting, that is, persistent. Non-persistent reactions might represent initial false-positive reactions, meaning that patients might unnecessarily avoid allergens. Objectives. To investigate the occurrence of both persistent and non-persistent patch test reactions, to explore possible explanations, and to investigate whether allergen-specific differences exist. Methods. A retrospective analysis was performed on patients who were patch tested at least twice between 1 January 1995 and 31 October 2016, with at least one positive patch test reaction to an allergen that had been retested. Both univariable and multivariable analyses were performed to investigate the influence of several factors on persistence. Results. Of 274 retested positive reactions in 119 patients, 183 (66.8%) reactions remained positive. The strongest predictor for non-persistence in both univariable and multivariable analyses was strength of the first patch test, with weak positive reactions being significantly less persistent. Regarding allergen groups, metals and fragrances were less persistent than other allergens. Conclusion. Weak positive reactions have a low persistence rate, and the dermatologist should be conservative in advising the patient on avoidance of these allergens, especially if clinical relevance is uncertain.

SUMMARYBackground Glucose sensors, such as FreeStyle® Libre, are innovative medical devices developed for diabetes patients as a replacement for classic glucose meters, ensuring continuous glucose monitoring without the disadvantage of regular skin finger pricks. Objectives To report several cases of allergic contact dermatitis caused by FreeStyle® Libre, and to report on isobornyl acrylate as a culprit allergen. Patients and Methods Fifteen patients presented with allergic contact dermatitis caused by FreeStyle® Libre. All but 1 were patch tested with a baseline series, and with pieces and/or ultrasonic bath extracts of (the adhesive part of) the glucose sensor. Isobornyl acrylate was patch tested, in various concentrations and vehicles, in 13 patients. Gas chromatography–mass spectrometry (GC-MS) of the sensors was performed. Results All patients reacted to the adhesive part of the sensor, and 12 patients were shown to be sensitized to isobornyl acrylate. Simultaneous reactions to other allergens were rarely observed. GC-MS showed the presence of isobornyl acrylate in the sensors. Conclusions Cases of allergic contact dermatitis caused by FreeStyle® Libre are increasingly being observed, and isobornyl acrylate is a relevant culprit allergen. Cross-reactivity to other acrylates was infrequently observed, but other, hitherto unidentified, contact allergens may still be present in the device.

Background: During rubber vulcanization, new compounds can be formed. Objectives: To report a case of allergic shoe dermatitis in which the search for the allergen ultimately led to the identification of dimethylthiocarbamylbenzothiazole sulfide (DMTBS). Methods: A female presented with eczema on her feet after wearing Sperry Top Sider® canvas sneakers. Patch testing was performed with the European baseline series, additional series, shoe materials, and extracts of shoe materials. Thin-layer chromatography (TLC) was performed for additional patch testing, and high-performance liquid chromatography and gas chromatography-mass spectometry were used for chemical analysis. Results: Positive reactions were found to thiuram mix (+), tetramethylthiuram monosulfide (TMTM) (+), shoe material (+), and shoe extracts in eth. (++) and acetone (+). The extracts did not contain TMTM or other components of thiuram mix. TLC strips yielded a positive reaction (+) to one spot, whereas chemical analysis gave a negative result. Thereafter, a similar sneaker from another patient with shoe dermatitis was analysed, and DMBTS was identified. New extracts of the shoe of our first patient were then also shown to contain DMTBS. DMTBS as culprit allergen was confirmed by positive patch testing with a dilution series with DMTBS. Conclusion: DMBTS was identified as the culprit allergen in shoe dermatitis, giving rise to compound allergy. The positive reaction to TMTM was considered to represent cross-reactivity.

SummaryBackground Temporary tattoos made with an extract of the jagua fruit (Genipa americana L.) are becoming increasingly popular. It is claimed that it is ‘dermatologically tested’ and does not contain p-phenylenediamine. Extracts of jagua and gardenia fruits have been used by indigenous people in South America, as well as in traditional Chinese medicine, for centuries. Genipin is currently used for its cross-linking effect in the manufacture of polysaccharides, and is being investigated for its anti-inflammatory and other properties. Objectives To report the presence of the allergenic substance genipin in a self-administered temporary tattoo dye made from the fruit juice of jagua (Genipa americana L.). Patients and methods A 39-year-old female who repeatedly applied ‘completely natural and 100% safe’ Earth Jagua® tattoo, obtained via the internet, to her left hand developed allergic contact dermatitis within 6 weeks. Analysis of the dye showed the presence of geniposide and genipin. Results Patch tests with the dye and with its main components, including genipin, gave strong positive reactions to the latter. There was no sensitization to other ingredients or p-amino compounds. Conclusions We report an extensively evaluated case of allergic contact dermatitis caused by a temporary Earth Jagua® tattoo. The allergen identified is genipin, a substance that is increasingly used for tattoos and as a therapeutic agent in medicine. This could result in an increase in the number of allergic reactions in the future.

SummaryBackground In Japan, allergic contact dermatitis caused by hair colouring agents is a considerable problem for those occupationally exposed and also for consumers. Over the last 20 years, p-phenylenediamine (PPD) has been a common allergen, with ∼7% positive patch test reactions. Objectives To investigate which ingredients caused allergic contact dermatitis related to hair dye and perming solutions in Japan, to assess whether PPD is suitable for screening for hair dye allergy, and to propose allergens for a Japanese hairdresser series. Methods We selected 19 hair cosmetic allergens, including PPD, Bandrowski's base, cysteamine HCl, and ammonium thioglycolate. Altogether 203 patients (26 males and 177 females) with suspected contact allergy to hair colouring or perming solutions at 14 hospitals in Japan were included. Results The highest prevalence of positive reactions (35.1%) was for PPD. p-Methylaminophenol and o-aminophenol were often positive, both in the PPD-positive and in the PPD-negative patients. Moreover, cysteamine HCl often yielded positive test reactions. Conclusions PPD is insufficient to diagnose contact allergy caused by to hair dyes. We recommend 13 allergens to be included in a Japanese hairdresser series.

SummaryBackground In 2016, dermatologists in Finland suspected contact allergy in several patients using moisturizers under the trade name Apobase®. Following a formulation change, Phenostat™, which is a mixture of phenoxyethanol, caprylhydroxamic acid, and methylpropanediol, was used as a preservative in Apobase® moisturizers in Finland. Objectives To confirm the suspected contact allergy to Apobase® cream, oily cream, and/or lotion, and to identify the specific contact allergen and define its optimal patch test concentration. Methods Thirty-nine patients with suspected contact allergy to Apobase® creams or lotion were patch tested in four Finnish dermatological clinics. The patch tests included old and new Apobase® formulas and their preservative agents: phenoxyethanol, methylpropanediol, and dilution series of Phenostat™ and caprylhydroxamic acid or its potassium salt. Results The patch tests showed positive reactions to the new Apobase® formulas, Phenostat™, and caprylhydroxamic acid or its potassium salt, but not to the old Apobase® formulas, methylpropanediol, or phenoxyethanol. Conclusions We found a new contact allergen, caprylhydroxyamic acid, which caused an epidemic of allergic contact dermatitis in patients using moisturizers containing this preservative. Whether the sensitizing capacity of caprylhydroxamic acid depends on the other chemicals used in Apobase® moisturizers needs further investigation.

SummaryBackground Patients with lower leg dermatitis, chronic venous insufficiency or chronic leg ulcers have a high prevalence of contact sensitization. Objectives To identify the current spectrum of contact allergens in these patients. Patients and methods Data of the Information Network of Departments of Dermatology on 5264 patients with the above diagnoses from the years 2003 to 2014 (study group) were compared with data on 4881 corresponding patients from 1994 to 2003 (historical control group) and with a current control group without these diagnoses (n = 55 510). Results Allergic contact dermatitis was diagnosed less frequently in the study group than in the historical control group (25.9% versus 16.9%; p

SummaryBackground Contact allergy is characterized by local skin inflammation that, in some cases, can result in systemic immune activation. Objectives To investigate whether IVIS SpectrumCT analyses can be used to detect the immune response induced by contact allergens. Methods Mice were repeatedly exposed to vehicle or allergens on the ears. The local and systemic responses were analysed at different times with the ProSense 750 FAST probe in IVIS SpectrumCT measurements. In addition, changes in ear thickness, cytokine profile in the skin and immunological phenotype in the draining lymph nodes and spleen were determined. Results Local inflammation was detected by ProSense 750 FAST and correlated with changes in ear thickness, cytokine profile and immunological phenotype following exposure to the strong contact allergen 2,4-dinitrofluorobenzene. Analysis of the systemic response with ProSense 750 FAST did not show any difference between allergen-exposed and control mice, although fluorescence-activated cell sorting analysis of the spleen showed increased numbers of γδ T cells and CD11b+CD11c+MHCII+ cells in allergen-treated mice. Conclusions IVIS SpectrumCT analyses with ProSense 750 FAST as the probe can be used to detect local immune responses induced by contact allergens.

Background Contact allergen prevalences often change. Continual surveillance is necessary to detect trends in sensitization rates and emerging allergens. Objective To identify the prevalence of, and trends in, the positive reactions to each allergen in the baseline series during a 12-year period in Thailand. Methods The medical records of 2803 patients who underwent patch testing at the Contact Dermatitis Clinic, Siriraj Hospital, between 2006 and 2018, were retrospectively reviewed. The baseline series used by the clinic was adapted from the European and the International baseline series. The patch testing results were subdivided into 2-year blocks in order to compare the prevalences of each allergen. Results The prevalences of positive reactions to nickel, fragrance mixes I and II, dichromate, cobalt, carba mix, methyldibromo glutaronitrile, paraben mix, neomycin sulfate, methylisothiazolinone (MI), epoxy resin, N-isopropyl-N-phenyl-4-phenylenediamine and the corticosteroids significantly decreased. Methylchloroisothiazolinone (MCI)/MI was the only allergen associated with a significant increase of positive reactions, from 2.4% to 10.7%. However, the proportion of positive reactions to MCI/MI decreased in the final 2-year period. Conclusions Approximately half of the substances in the screening patch test series showed a decline in the number of positive reactions, whereas MCI/MI showed an increasing prevalence.

Background: Allergic contact dermatitis caused by henna-based hair-colouring products has been associated with adulteration of henna with p-phenylenediamine (PPD). Objectives: To develop a testing approach based on in vitro techniques that address key events within the skin sensitization adverse outcome pathway in order to evaluate the allergenic potential of hair-colouring products. Methods: The following in vitro assays were used to test the sensitizing capacity of hair dye ingredients: the micro-direct peptide reactivity assay (mDPRA); the HaCaT keratinocyte-associated interleukin (IL)-18 assay; the U937 cell line activation test (U-SENS)/IL-8 levels; the blood monocyte-derived dendritic cell test; and genomic allergen rapid detection (GARD skin). Those techniques with better human concordance were selected to evaluate the allergenic potential of 10 hair-colouring products. Results: In contrast to the information on the label, chromatographic analyses identified PPD in all products. The main henna biomarker, lawsone, was not detected in one of the 10 products. Among the techniques evaluated by testing hair dye ingredients, the mDPRA, the IL-18 assay, GARD skin and the U-SENS correlated better with human classification (concordances of 91.7%-100%) and were superior to the animal testing (concordance of 78.5%). Thus, these assays were used to evaluate hair-colouring products, which were classified as skin sensitizers by the use of different two-of-three approaches. Conclusions: Our findings highlight the toxicological consequences of, and risks associated with, the undisclosed use of PPD in henna-based “natural” “real-life” products. (Less)

SummaryBackground Majantol® [2,2-dimethyl-3-(3-methylphenyl)propan-1-ol; CAS no. 103694-68-4] has been identified as a contact allergen in humans, despite the lack of sensitizing properties according to animal tests. The question was raised of whether impurities, specifically organochlorines, in Majantol® might have been the reason for positive patch test reactions in the past. Objectives To assess the allergenic potential in terms of elicitation via patch testing with a standard market-quality version of Majantol® (‘normal’) with a normal content of organochlorine impurities, as compared with an ultra-purified version of Majantol® (‘pure’), without detectable organochlorine impurities. Methods Between 1 October 2013 and 31 December 2014, two different Majantol® patch test preparations of the above-mentioned quality were tested 5% pet. in parallel in the ‘monitor series’, that is, together with the baseline series, in 8005 consecutive patients from 33 departments of dermatology of the Information Network of Departments of Dermatology (IVDK). Results Fifty-three of 7740 [0.69% (95%CI: 0.51–0.87)] patch tested patients reacted to at least one Majantol® preparation. The majority (n = 32) (60.4%) reacted to both preparations, 13 (24.5%) reacted to the ‘normal’ version only, and 8 (15.1%) reacted to the ‘pure’ version only. There was good concordance between results [Cohen's kappa 0.75 (95%CI: 0.65–0.85)], and there was no significant difference in frequency or intensity between the two preparations. More doubtful or irritant reactions than positive reactions were observed, and> 80% of all positive reactions were weak positive. Conclusion Organochlorine impurities are very probably not the cause of allergic reactions to Majantol®.

SummaryBackground Cross-reactions and co-sensitizations are of great importance in understanding contact allergy and exposure sources. Objectives To investigate common cross-reactions and co-sensitizations in p-phenylenediamine (PPD)-sensitized and toluene-2,5-diamine (TDA)-sensitized individuals. Methods From our patch test population, 8036 patients patch tested with the European baseline series were extracted. Readings had to be performed at least on day 3 according to ICDRG guidelines. Results Two hundred and fifty-one patients were sensitized to PPD and/or TDA; 231 patients were sensitized to PPD, and 109 to TDA. Significant differences were observed regarding the strengths of patch test reactions to PPD and number of cross-reactions. For TDA, a difference was found between all reaction strengths, except between + and ++ strengths. PPD-sensitized individuals were more likely to be sensitized to carba mix, cobalt chloride, colophonium, p-tert-butyl phenolformaldehyde resin, paraben mix, and methylisothiazolinone. TDA-sensitized individuals were more often sensitized to carba mix. Conclusions Cross-reactivity was commonly found among individuals sensitized to PPD or TDA, and was strongly related to the strength of the patch test reaction. Regarding co-sensitizations, a frequently appearing or common exposure source could not be determined. However, modification of the allergen by, for example, the skin microbiota may have caused the formation of molecules that are, for the human immune system, indistinguishable from PPD.

SummaryBackground Ethylhexylglycerin is a relatively new cosmetic ingredient that is used for its surfactant, emollient, skin-conditioning and antimicrobial properties. Since 2002, it has been occasionally reported as a contact allergen. Objectives To report on 13 patients who presented with allergic contact dermatitis caused by ethylhexylglycerin, evaluated at two Belgian university patch test clinics during the period 1990–2015. Patients and methods The patients were patch tested with the European baseline series, a cosmetic series, and – if indicated – additional series. Both the cosmetic products used and their single ingredients were patch tested. Results All but one of the ethylhexylglycerin-allergic patients were female, with a median age of 43 years (range: 29–81 years), most often suffering from dermatitis on the face, and sometimes on the hands and/or axillae. As the culprit products, leave-on cosmetics were identified, including a high number of proclaimed ‘hypo-allergenic’ and ‘preservative-free’ facial creams, sun protection creams, and deodorants. Conclusions Ethylhexylglycerin is a rare, but highly relevant, cosmetic sensitizer, even in those products advertised to be safe for consumers. Targeted patch testing with ethylhexylglycerin 5% pet. is very useful, and routine patch testing in a cosmetic series may be considered. Higher test concentrations might be indicated in selected cases.

Summary Background Sorbitan sesquioleate (SSO) has been added to fragrance mix I (FM I) as an emulsifier since the 1990s. Being a contact allergen itself, SSO has the potential to cause false-positive reactions to FM I. Recent results obtained with selected FM I-positive patients have shown that 5% have concomitant positive reactions to SSO. Objectives To investigate the 5-year prevalence of contact allergy to SSO and evaluate the importance of SSO allergy when patch test results for FM I are interpreted. Methods This was a retrospective database study of consecutively patch tested eczema patients (n = 4637) from 2010 to 2014. All patients were tested with our baseline series including FM I and SSO 20% in pet. Results Sensitization to SSO was identified in 9 (0.2%) patients. The proportion of FM I-positive patients with concomitant positive reactions to SSO was 1.4%. Conclusions SSO is a rare cause of contact allergy, with a 5-year prevalence of 0.2% in consecutively tested patients. Contact allergy to the emulsifier does not play a major role when the overall frequency of contact allergy to FM I is evaluated. However, to correctly diagnose individual patients, concomitant patch testing with FM I and SSO is encouraged.

BACKGROUND: Full assessment of patients with (occupational) contact dermatitis should ideally include a standardized investigation of irritant exposures in addition to information pertaining to possible allergy guiding the selection of allergens (haptens) to be tested. Positive results of skin tests, performed according to current guidelines, are evaluated in terms of their clinical relevance. However, such diagnostic information is hitherto ill-represented in clinical documentation systems (patch test software) serving departmental documentation needs, and also in surveillance registries based upon these. OBJECTIVES: To develop, implement as a pilot study, and analyse concerning feasibility and contents a new concept of representing a full scope of diagnostic information utilized when diagnosing patients with (occupational) contact dermatitis. METHODS: Based on a European working group discussion on items to document and catalogue lists to use for this purpose, an online documentation system to collect data was set up, followed by a pilot use involving 9 dermatology departments across Europe. RESULTS: Data on 176 patients with suspected occupational hand dermatitis were included. Data were analysed with regard to occupations, product categories, substances (haptens), source of information the evaluation was based upon, and various combinations of these factors, to illustrate the usefulness of the proposed data representation. CONCLUSIONS: An improved method of data collection is presented which more accurately links allergen to exposure and to clinical disease and patient history, and thus better represents clinical relevance. This enables more precise analysis of causation of contact dermatitis, occupational or non-occupational, and thereby better targeting of prevention on an individual basis. In addition to the benefits for individual documentation, the surveillance of contact dermatitis is expected to be enhanced by the suggested concept, allowing a more in-depth investigation of profiles of patients at risk for certain allergies, while still serving other well-proven purposes, eg time trend analyses.

OBJECTIVES: To determine the prevalence of atopic dermatitis (AD) in the general European population and to assess differences in contact allergy and avoidance of products between subjects with AD in lifetime and those who had not. MATERIALS AND METHODS: In five European countries (The Netherlands, Germany, Italy, Portugal and Sweden) a random sample of 12 377 participants, aged 18 to 74 years were interviewed using a standardized questionnaire. Questions were asked about previous atopic dermatitis and avoidance of products because of a skin reaction. A random sample of 3119 participants was patch tested. TRUE Test panel 1, 2 and 3 and investigator-loaded chamber systems were used, testing for a total of 47 allergens, including the individual fragrance allergens of fragrance mix (FM) I and FM II. Reading was performed at day 3. RESULTS: The physician-diagnosed lifetime prevalence of AD was 7.1% (95% CI 6.7-7.6). The age-standardized physician diagnosed life time prevalences of AD stratified per country were: Germany: 9.4% (95% CI 8.5-10.3); The Netherlands: 8.5% (95% CI 7.2-10.1); Sweden: 7.2% (95% CI 6.1-8.4); Italy 4.2% (95% CI 3.3-5.3); Portugal: 3.3% (95% CI 2.6-4.2). The prevalence of contact allergy to at least one allergen was not significantly different between those with AD in lifetime (31.1%) and those without AD (27.8%). Males with AD were significantly more sensitized to allergens of TRUE Test panel 2 (14.9%) than those without AD (6.9%) (P = .026). The prevalence of contact allergy to individual allergens was not significantly different for those with AD and those without, except for p-phenylenediamine in males: AD (4.0%), no AD (0.7%) (P = .023). The prevalence of a positive patch test reaction to the group of preservatives was slightly albeit not significant (P

INTRODUCTION: Polysensitization is currently defined as contact sensitization to three or more non-related allergens of the European baseline series. Reported prevalences of polysensitization are mainly from clinical populations, as studies in the general population are scarce. OBJECTIVES: To determine the prevalences of polysensitization in the European general population. MATERIALS AND METHODS: In five European countries (The Netherlands, Germany, Italy, Portugal and Sweden) a random sample (N=3119) from the general population (18-74 years) was patch tested. Patch testing was performed according to the International Contact Dermatitis Research Group guidelines. Both TRUE Test and investigator-loaded chamber systems were used, testing for a total of 47 allergens, including the individual fragrance allergens of fragrance mix (FM) I and FM II. Reading was performed at day 3. Polysensitization was defined as sensitization to 3 or more non-related allergens. The following positive reactions were pooled as one: FM I and one or more substances of FM I; FM II and one or more substances of FM II; carba mix and thiuram mix; mercapto mix and 2-mercaptobenzothiazole; formaldehyde, quaternium 15, diazolidinyl urea and imidazolidinyl urea. RESULTS: Overall, the age-standardized prevalence of polysensitization was 2.6% (95% confidence interval [CI] 2.1-3.2). The agestandardized prevalences stratified per country were: The Netherlands: 4.0% (95% CI 2.5-6.0); Germany: 3.2% (95% CI 2.3-4.4); Portugal: 2.6% (95% CI 1.5-4.3); Sweden: 1.5% (95% CI 0.7-2.9); Italy 1.1% (95% CI 0.5-2.3). Of the polysensitized population, the majority was female ≥ 40 years (42.0%) and minority was male

Background Multiple contact allergies (MCAs) are defined as three or more positive patch test reactions to unrelated antigens. Factors associated with MCAs include female sex, older age, and certain eczema sites. Objectives To investigate the prevalence of MCAs, risk factors for their development, and patterns of allergen combinations. Methods This retrospective, case-control study was conducted on patients suspected of having allergic contact dermatitis who had been patch tested with a baseline series in the period January 2007 to December 2016. Results Of the 2178 included patients, 531 (24.4%) had MCAs. A multivariate analysis showed that a generalized distribution of dermatitis represented the highest risk factor (odds ratio [OR] 3.97), followed by a history of metal allergy (OR 3.18). The other significantly associated factors were, in order of decreasing frequency, the dermatitis sites (hands/feet, extremities, and face), age ≥25 years, and occupationally related dermatitis; their ORs were Conclusions The factors that were significantly associated with MCAs were identified. The ranking of the common contact allergens among MCA patients was comparable with that of non-MCA patients. Metal and fragrance allergens were frequently found to cause concurrent positive reactions in MCA patients.

Background Allergic contact dermatitis (ACD) caused by topical ophthalmic medications is often overlooked. Objectives To study the demographic characteristics, lesion locations and associated medical conditions of the patients with ACD caused by ophthalmic drugs, and to identify the most common allergenic culprits, as well as trends in frequencies over the years. Methods From January 1990 until December 2016, 16 065 patients were investigated in our clinic; all patients with a positive patch test reaction to an eye medication or its ingredient(s) having caused ACD were assessed. For each allergen identified, the number of positive test results as compared with the total number of those in the total population, as well as trends across three periods, namely 1990 to 1998, 1999 to 2007, and 2008 to 2016, were studied. Results One hundred and eighteen patients (0.7%) presented with positive patch test reactions to ingredients of and/or topical ophthalmic medications. Aminoglycoside antibiotics, followed by corticosteroids, as pharmacologically active ingredients, as well as wool alcohols, thiomersal, and benzalkonium chloride, as excipients, were the most frequent culprits. Chloramphenicol showed a decreasing trend of positive reactions over time, whereas reactions to tobramycin increased. Conclusion ACD caused by eye medication is mainly attributable to active principles, but other excipient ingredients, beside the products "as is," should be tested as well.