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Background: Propolis was added to the European baseline series (EBS) in 2019., Objectives: To investigate the frequency and relevance of positive patch tests to propolis in the EBS and to study co-reactivities., Patients and Methods: Retrospective study in patients patch tested between June 2019 and November 2023 in a university hospital in Amsterdam, The Netherlands., Results: Of 3134 consecutive patients, 299 (9.5%) had a positive reaction to propolis 10% pet. Only nine reactions (3%) were judged to be clinically relevant. There were significant co-reactivities to Myroxylon pereirae resin (balsam of Peru), colophonium, fragrance mixes 1 and 2, and to limonene and linalool hydroperoxides. A steep increase in rates of positive reactions to propolis was observed from 2020 to 2023. This was highly likely the result of the replacement of Chinese propolis with Brazilian propolis by the manufacturer., Conclusions: Positive patch tests for propolis are very frequent in Amsterdam, but only a few of these reactions are relevant. Most are probably (pseudo-)cross-reactions in patients with fragrance allergies. Propolis in the EBS has very limited value for dermatologists and patients in The Netherlands. Changes in patch test materials should be provided to all users to avoid misinterpretation of patch test results., (© 2024 The Author(s). Contact Dermatitis published by John Wiley & Sons Ltd.)

Background: Patch testing for multiple cross-reactive allergens for allergic contact dermatitis (ACD) may not be necessary because of copositivity., Objectives: We evaluated the formaldehyde group allergens to determine the optimal, most cost-effective allergens to test., Methods: A retrospective analysis of Mayo Clinic (1997-2022) examined the well-established copositive formaldehyde group: formaldehyde, quaternium 15, hexahydro-1,3,5-tris(2-hydroxyethyl)triazine, diazolidinyl urea, imidazolidinyl urea, toluenesulphonamide formaldehyde resin, DMDM hydantoin, and ethyleneurea melamine formaldehyde mix. Patch Optimization Platform identified which single formaldehyde-related allergen optimally captures patients with clinically relevant ACD. Next, Patch Optimization Platform determined the optimal additional 1, 2, 3, etc. allergens. Cost per patch test was $5.19 (Medicare 2022)., Results: A total of 9832 patients were tested for all listed allergens, with 830 having positive patch test results. Patch Optimization Platform determined that quaternium 15 alone captures 53% of patients with ACD to the formaldehyde group; adding the optimal second allergen (formaldehyde 1%) captures 78%; the optimal 5 top allergens capture >94% of patients. The incremental cost per additional diagnosis increased up to 44-fold as the number of allergens tested increased., Limitations: Data are from a single institution, and the cost per test was fixed according to Medicare Part B in 2022., Conclusions: For diagnosing ACD, we recommend considering an optimized allergen selection algorithm., Competing Interests: Conflicts of interest None disclosed., (Copyright © 2024 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.)

Drug causality assessment in severe cutaneous adverse reactions (SCARs) remains challenging. We investigated the usefulness of in-vivo drug patch tests (PT), ex-vivo interferon (IFN)-γ enzyme-linked immunospot (ELISpot) assay, and lymphocyte transformation test (LTT) in 30 SCARs patients within the past 36 months. Drug PT yielded a 20% positivity rate (n = 6), while IFN-γ ELISpot and LTT showed positive rates of 56.67% (n = 17) and 41.38% (n = 12), respectively. Combining the three tests resulted in an overall positive rate of 66.67% (n = 20) of cases. IFN-γ ELISpot offered additional positivity, especially with oxypurinol. Employing a combined diagnostic approach may enhance the chances of obtaining a positive result., (© 2024 Japanese Dermatological Association.)

Background: Machine learning (ML) offers an opportunity in contact dermatitis (CD) research, where with full clinical picture, may support diagnosis and patch test accuracy., Objective: This review aims to summarise the existing literature on how ML can be applied to CD in its entirety., Methods: Embase, Medline, IEEE Xplore, and ACM Digital Library were searched from inception to February 7, 2024, for primary literature reporting on ML models in CD., Results: 7834 articles were identified in the search, with 110 moving to full-text review, and six articles included. Two used ML to identify key biomarkers to help distinguish between allergic contact dermatitis (ACD) and irritant contact dermatitis (ICD), three used image data to distinguish between ACD and ICD, and one used clinical and demographical data to predict the risk of positive patch tests. All studies used supervision in their ML model training with a total of 49 704 patients across all data sets. There was sparse reporting of the accuracy of these models., Conclusions: Although the available research is still limited, there is evidence to suggest that ML has potential to support diagnostic outcomes in a clinical setting. Further research on the use of ML in clinical practice is recommended., (© 2024 The Author(s). Contact Dermatitis published by John Wiley & Sons Ltd.)

Introduction: The growing presence of allergens in materials and scarce data on allergic contact dermatitis in children has increased our need to refine its diagnosis in this population. We aimed to analyze children's specific responsivity to highly reactive subcomponents of Fragrance mix I, Fragrance mix II, and Textile dye mix from the European baseline series., Methods: We retrospectively analyzed patch test records of children aged 2 to 18 who underwent patch testing with the European baseline series between 2014 and 2022 in Israel., Results: A total of 367 children were included in the study. In all, 160 children had positive results; 43 patients reacted to one of the mixes, and 20 performed further testing. Eleven of them completed the extended series at the exact same times as the regular European series, which benefited children. Farnesol was the most reactive compound (30.8%)., Conclusions: Performing the extended European series provides a more accurate and time-efficient allergic contact dermatitis diagnosis. Farnesol reactivity appears prominent in children and may justify tighter product regulations., (© 2024 the International Society of Dermatology.)

Background: Isocyanates are used as starting materials of polyurethane (PU) products. They are relatively important occupational skin sensitizers., Objectives: To analyse results of a large isocyanate patch test series of 19 isocyanate test substances and 4,4'-diaminodiphenylmethane (MDA), a marker of 4,4'-diphenylmethane diisocyanate (MDI) hypersensitivity., Methods: Test files were screened for positive reactions in the isocyanate series. Patients with positive reactions were analysed for occupation, exposure and diagnosis., Results: In 2010-2019, 53 patients had positive reactions in the series (16% of 338 patients tested). MDA, the well-established screening substance for MDI allergy, was positive in 30 patients, an in-house monomeric MDI test substance in 23 patients and 3 different polymeric MDI test substances in 19-21 patients. We diagnosed 16 cases of occupational allergic contact dermatitis (OACD) from MDI including 3 pipe reliners. Hexamethylene-1,6-diisocyanate (HDI) oligomers in paint hardeners caused 5 cases of OACD, more cases than 2,4-toluene diisocyanate (TDI; n = 3) and isophorone diisocyanate (IPDI; n = 1) put together., Conclusions: In contrast to previous studies, polymeric MDI test substances were not superior to a monomeric MDI. Pipe reliners may get sensitised not only by epoxy products and acrylates but also by MDI in hardeners of PU pipe coatings. HDI oligomers were the second most important causes of OACD after MDI., (© 2024 The Author(s). Contact Dermatitis published by John Wiley & Sons Ltd.)

Background The International Contact Dermatitis Research Group (ICDRG) grading is the gold standard and is used to interpret patch test results in allergic contact dermatitis (ACD). The ICDRG readings include a combination of visual and palpation findings. Digital photography limits palpation. An alternative scoring system exists to analyse 2D images and interpret patch test readings in teledermatology (TD). Aim To compare tri-partite scoring system (TPSS) (TD) with ICDRG (face-to-face) and to assess the feasibility of TPSS by TD. Methods In this observational study, two investigators each scored the patch test readings for 78 patients at the 48th h, 96th h and on the 7th day. Results The TPSS has a sensitivity of 100%, specificity of 93.34%, positive predictive value of 91.67% and negative predictive value of 100%. At a confidence interval of 95%, Cohen's kappa (0.90) indicated excellent agreement between both investigators. The concordance between both scoring systems was at 93.2% for agreement and 6.82% for disagreement. Polysensitisation (6 patients with 16 allergens) was detected equally in both methods. Limitation A single centre study. Conclusion The readings obtained by TPSS were in agreement with ICDRG. TPSS can reduce the number of patient visits by 50% and may be used during COVID-19 times and beyond.

Background: The number of commercially available plant allergens/extracts is limited and therefore patch testing with fresh/dried plant material may be a necessary supplement in diagnosing plant allergy., Objectives: To evaluate the usefulness of patch testing with plants "as is" compared to patch testing with commercial and in-house produced plant test materials and to report on species eliciting positive patch test reactions., Patients/materials/methods: Consecutive eczema patients, who were patch tested between January 2019 and December 2023 and who had at least one positive reaction to a plant allergen and/or extract and/or plant "as is" were included in the study., Results: A total 57 out of 1893 patients tested (3%) were sensitised to plants. Compositae plants were the most frequent sensitizers, followed by tomato, tulipalin A, falcarinol, and Philodendron plants. In 12 patients (21%), the diagnosis was based on patch testing with fresh plants only. Occupational sensitization occurred in 32%. Other sensitizers included Hydrangea, Pelargonium zonale, and Monstera., Conclusions: A large minority of plant-sensitised patients would have been undiagnosed without patch testing with plants "as is." Most of the culprit plants were known sensitizers, but not commercially available, and these and new species taken into cultivation makes patch testing with fresh plants unavoidable and worthwhile., (© 2024 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: Existing literature has questioned the sensitivity of patch testing (PT) with cotrimoxazole (CTX) in the study of drug hypersensitivity., Objectives: Assess the sensitivity of PT with CTX in non-immediate cutaneous adverse drug reactions (CADR)., Patients/materials/methods: Retrospective analysis (2000-2022) of PT with an antibiotic series including CTX 10% pet (Chemotechnique Diagnostics©) performed according to ESCD guidelines in patients with suspected non-immediate CADR reactions to CTX. Some patients were additionally tested with in-house preparations of CTX from Bactrim DS® tablets at 10% in pet or water and trimethoprim 10% pet (Laboratórios Edol©)., Results: Sixty-four patients (48F/16M; mean age 47 ± 18) were included, mostly with maculopapular exanthema (51, 80%). Notably, CTX was sole suspect in 24 patients. There was no positive reaction to CTX at 10% from Chemotechnique or Bactrim DS® tablets prepared at 10% pet for patch testing. One patient reacted exclusively to trimethoprim with 1+ reaction. Two patients had a faint reaction (1+) only with the powder of Bactrim DS® tablets in water at D2, but as the reactions faded completely in 24 or 48 h, they were interpreted as irritant non-specific reactions., Conclusion: These findings suggest that patch testing may lack sufficient sensitivity to diagnose CTX-induced non-immediate CADR. Therefore, clinicians should be cautious interpreting CTX patch test results., (© 2024 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: Photoallergic contact dermatitis (PACD) is a delayed hypersensitivity reaction to allergens only in the presence of ultraviolet radiation in sunlight. Photopatch testing (PhotoPT) is necessary to confirm the diagnosis of PACD. There are few published studies of PhotoPT in North America., Objective: To summarise the results of patients photopatch tested by members of the North American Contact Dermatitis Group (NACDG), 2009-2020., Methods: Retrospective analysis of patient characteristics and PhotoPT results to 32 allergens on the NACDG Photopatch Test Series., Results: Most of the 454 tested patients were female (70.3%), 21-60 years old (66.7%) and White (66.7%). There were a total of 119 positive photopatch tests. Sunscreen agents comprised 88.2% of those, with benzophenones responsible for over half of them. Final diagnoses included PACD in 17.2%, allergic contact dermatitis (ACD) in 44.5%, polymorphous light eruption (PMLE) in 18.9% and chronic actinic dermatitis (CAD) in 9.0% of patients., Conclusions: In 454 patients with suspected photosensitivity referred for photopatch testing in North America, approximately one-fifth had PACD. Sunscreen agents, especially benzophenones, were the most common photoallergens. Other common diagnoses included ACD, PMLE and CAD. Photopatch testing is an important tool for differentiating these conditions., (© 2024 The Author(s). Contact Dermatitis published by John Wiley & Sons Ltd.)

Patch testing is the only clinically applicable diagnostic method for Type IV allergy. The availability of Type IV patch test (PT) allergens in Europe, however, is currently scarce. This severely compromises adequate diagnostics of contact allergy, leading to serious consequences for the affected patients. Against this background, the European Society of Contact Dermatitis (ESCD) has created a task force (TF) (i) to explore the current availability of PT substances in different member states, (ii) to highlight some of the unique characteristics of Type IV vs. other allergens and (iii) to suggest ways forward to promote and ensure availability of high-quality patch testing substances for the diagnosis of Type IV allergies throughout Europe. The suggestions of the TF on how to improve the availability of PT allergens are supported by the ESCD, the European Academy of Allergy and Clinical Immunology, and the European Academy of Dermatology and Venereology and intend to provide potential means to resolve the present medical crisis., (© 2024 The Authors. Contact Dermatitis published by John Wiley & Sons Ltd.)

Allergy to penicillin can occur via any of the 4 types of Gel-Coombs hypersensitivity reactions, producing distinct clinical histories and physical examination findings. Treatments include penicillin discontinuation, and depending on the type of reaction, epinephrine, antihistamines, and/or glucocorticoids. Most beta-lactams may be safely used in penicillin-allergic patients, with the possible exception of first-generation and second-generation cephalosporins. Penicillin testing includes skin testing, patch testing, and graded challenge. The selection of the type of testing depends on the clinical setting, equipment availability, and type of hypersensitivity reaction. Desensitization may be used in some cases where treatment with penicillins is essential., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Background: Increasing trends of oxidized linalool contact allergy have been reported. However, the impact of reactivity and dose in eliciting allergic contact Dermatitis caused by linalool hydroperoxides is insufficiently investigated. Objectives: To perform repeated open application tests (ROATs) using the real-world concentrations of linalool hydroperoxides in patients and control participants. Materials and Methods: Patients who previously had a positive (patients) and a negative (controls) patch test reaction to linalool hydroperoxides 1.0% in petrolatum were patch tested with a dilution series of linalool hydroperoxides preparations and asked to perform ROAT twice daily with 3 concentrations of linalool hydroperoxides creams and a negative control cream for 28 days. The creams contain 44, 140, and 440 PPM of linalool hydroperoxides, representing real-world doses reported in consumer products. Results: Of all 47 participants, 31 were linalool hydroperoxides contact allergy patients, and 16 were controls. One patient had a positive ROAT reaction in the area where cream at the highest concentration of linalool hydroperoxides was applied for 28 days. Conclusions: Repeated exposure to creams containing linalool hydroperoxides at real-life concentrations could rarely elicit an allergic reaction on intact skin after 4 weeks.

Background: Patch test is the gold standard for diagnosing allergic contact dermatitis. Conventionally, the patches are applied for 48 h, which in tropical weather conditions causes excessive sweating, leading to irritation, and sometimes the patches come off, making the test inconclusive., Objective: To compare the patch test positivity after 24 and 48 h of occlusion time in patients of allergic contact dermatitis, using standard allergen concentration., Materials and Methods: Clinically suspected patients of allergic contact dermatitis were enrolled and patch tested using the Indian Standard Series, parthenium acetone extracts (1:50, 1:100 and 1:200 dilutions) and patient material. Patches were applied in duplicate on either side of the back, using a random number table. One set of patches was removed after 24-h of occlusion, while the other set after 48-h. Readings were performed at 48- and 96-h by two independent dermatologists, blinded to the duration of occlusion., Results: The study had 97 adult patients (58 males and 39 females; mean age: 48.12 ± 13.07 years). A total of 133 and 142 positive reactions were observed after 48 h occlusion at 48 and 96 h reading, respectively. Of these 117 (87.9%) and 132 (92.9%) patches were positive and concordant and noted at 24 h occlusion time. The Cohen's kappa coefficient were 0.94 for 48 h and 0.97 for 96 h reading, hence showing an almost complete agreement (ⱪ > 0.81) between patches occluded for 24 and 48 h., Conclusion: Though there is no significant difference in patch test positivity among ISS allergens after either occlusion time, 48 h occlusion performs significantly better compared with 24 h, when reactions of all allergens (ISS, patient material and parthenium acetone extract) are analysed together., (© 2024 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Exogenous allergens, found in cosmetic products, jewelry items, antiseptics and antibacterials, plants, and solvents, can cause clinical allergic contact Dermatitis (ACD). To help identify and discern which allergen is causing ACD, clinicians use patch tests, but they can yield false-negative results at times. Examining potential reasoning for false negatives is particularly helpful when a patient's history and physical examination strongly suggest ACD, and the patch test is negative. A strong history and physical presentation suggestive of ACD warrants additional patch testing or other methods to verify a false-negative patch test result. We conducted a literature review to compile various reasonings and solutions for false-negative patch tests in suspected ACD patients. Utilizing EMBASE, Scopus, PubMed, and Google Scholars, 49 articles were included by using search terms such as "False negative patch test" or "False-negative patch test" and "allergic contact Dermatitis," or "ACD." Common factors that led to false-negative patch test results include low allergen concentration, inadequate percutaneous penetration, technique error, immunosuppressive therapy, and ultraviolet exposure. Potential solutions include using different vehicles, concentration, increasing reading time, repeating the patch test, intradermal testing, and repeat open application testing. If a false-negative patch test is suspected, then intradermal testing can be administered to ensure the specificity of the patch test result. Considering the main contributing factors and solutions to false-negative patch tests, clinicians can accurately diagnose ACD and administer proper treatment plans.

Background: Supplemental patch testing is an adjunct to standard patch test screening series. Objective: To determine the demographics, characteristics, frequency, relevance, and interpretation of patch test reactions for supplemental patch testing. Methods: Retrospective study of patients tested 2017-2020 with North American Contact Dermatitis Group (NACDG) and supplemental screening series (Supplemental Series A [SSA], Supplemental Series B [SSB]). Demographics, characteristics, reaction strengths, relevance, and final interpretation were recorded. Results: Cohort included 791 patients; 73.5% female, 68.6% age >40 years. 74.1% were White, 15.2% Black, 5.7% Asian, and 1.5% Hispanic. The most common Dermatitis sites were scattered/generalized (27.2%), face (24.0%), and hands (23.5%). For 2017-2018 and 2019-2020, respectively, 82% (318/388) and 78.4% (316/403) had ≥1 "allergic" reaction. In addition, 13.5% (52/385) and 11.7% (47/403) had SSA reactions, and 38.1% (115/302) and 31.5% (101/321) had SSB reactions. In the 87 (2017-2018) and 99 (2019-2020) patients with negative NACDG testing, 17 (19.5%) and 12 (12.1%) had supplemental reactions. Of the 34 supplemental allergens with reaction frequency ≥1%, 58.8% (20/34) are not part of the American Contact Dermatitis Society 90 (2020) or NACDG 2021-2022 screening series. The highest frequency allergens from this group were dodecyl and octyl gallate, cinnamic alcohol, phenyl salicylate, hexahydro-1,3,5-tris-(2-hydroxyethyl) triazine, and abitol. Conclusions: Supplemental patch testing identifies additional relevant allergens in patients with suspected allergic contact Dermatitis.

Background: Allergic contact Dermatitis (ACD) is a common condition within the pediatric population. Patch testing is an important way to identify relevant allergens. Objective: To provide an update of the common contact allergens seen in children based on patch testing data at our institution from 2016 to 2020. Methods: We performed a retrospective analysis of patch test data from children aged 1-18 years from 2016 to 2020 at Mayo Clinic. Reaction rates were compared to the rates reported by the Pediatric Contact Dermatitis Registry (PCDR). Results: One hundred ninety-two children aged 1-18 were patch tested to various allergens. A total of 15,457 allergens were tested, with 291 positive tests. The top 5 allergens with highest positive reaction rates were hydroperoxides of linalool, hydroperoxides of limonene, methylisothiazolinone, nickel, and cobalt. Seven of the top 38 allergens with the highest reaction rates are not currently included in the Mayo Clinic Pediatric Patch Test Series, and 11 are not currently included in the Pediatric Baseline Series (as developed by the Pediatric Contact Dermatitis Workgroup). Conclusions: Patch testing is a useful tool to diagnose children with ACD. With new products and exposures, there is an opportunity to expand current pediatric patch testing series.

Background: Quantitative risk assessment (QRA) for skin sensitization is used to derive safe use levels of sensitising fragrance ingredients in products. Post-marketing surveillance of the prevalence of contact allergy to these ingredients provides relevant data to help evaluate the performance of these measures., Objectives: To determine a suitable patch test concentration for five fragrance materials that had hitherto not been tested on a regular basis. These concentrations are then to be used in a surveillance study with patch testing consecutive patients over an extended monitoring period., Materials and Methods: Furaneol, CAS.3658-77-3; trans-2-hexenal, CAS.6728-26-3; 4,8-dimethyl-4,9-decadienal, CAS.71077-31-1; longifolene, CAS.475-20-7; benzaldehyde, CAS.10052-7, were patch tested with other fragrance allergens in four clinics. Patch testing was conducted in three rounds, starting with the lowest concentrations of the five ingredients. The doses were increased in the subsequent rounds if no late-appearing positive reactions and virtually no irritant reactions were reported., Results: Overall, 373 patients were tested. No positive allergic reaction was reported to the five ingredients. Patch test results of other fragrance allergens are reported., Conclusions: The highest test concentrations are each considered safe for patch testing consecutive patients. Further surveillance based on these preparations will evaluate the hypothesis that QRA-driven consumer product levels of these fragrances can prevent sensitization., (© 2024 The Authors. Contact Dermatitis published by John Wiley & Sons Ltd.)

Background: Doubtful reactions in patch testing are infrequently reported in the literature; however, recent reports have suggested they be assessed with the same scrutiny as stronger reactions., Objective: Assess the clinical relevance of doubtful reactions in patch testing., Methods: Retrospective study of 1514 patients comprehensively patch tested via the NACDG standard series and additional allergens based on history. The clinical relevance of each reaction was graded based on the NACDG scale: definite, probable, possible, past, unknown and irritant. Reactions were considered 'unique' if an additional mild-to-strong reaction to the same chemical at a different concentration was not observed., Results: 68.9% (1043) of patients demonstrated at least 1 doubtful reaction. Of 4453 total doubtful reactions, 92.2% (4106) were unique. Only 3.3% (137) and 12.2% (500) of these were determined to be of definite or probable clinical relevance respectively. 'Fragrance' was the most common allergen family present among the unique definite doubtful reactions (37). However, 24 (64.9%) of these also had a stronger reaction to another fragrance. Cocamidopropyl betaine was the second most frequent allergen demonstrating definite doubtful reactions (27) and unique in 85.2% (23) of cases. Methylchloroisothiazolinone/methylisothiazolinone (MCI/MI) was most prevalent (36) but less frequently unique (58.3%, 21)., Conclusions: Doubtful reactions may not be as impactful to clinical decision making as theorised in the literature. Few demonstrate definite clinical significance, and many have related stronger reactions that capture them for clinical purposes. Identification of doubtful reactions to cocamidopropyl betaine and MCI/MI may be of greatest significance as they most frequently were not supported by stronger reactions., (© 2024 The Authors. Contact Dermatitis published by John Wiley & Sons Ltd.)

Introduction: Atopic dermatitis (AD) is a chronic and relapsing inflammatory skin disease mainly affecting children. Similarly, Allergic contact dermatitis (ACD) is an inflammatory skin disease, but unlike AD it results from direct exposure to an external agent. Theoretically, the impaired skin barrier facilitates the penetration of potential allergens. Therefore, AD patients are at risk for an associated ACD, exacerbating their skin condition. Because eczema is similar, performing a patch test (PT) for the differential diagnosis is essential., Methods: In this cross-sectional transversal study, we performed a PT with 30 sensitizers in 26 children with AD, selected according to established criteria for suspected ACD, and treated at an AD center of a pediatric university hospital in Rio de Janeiro. Clinical presentation, patient profile, main sensitizers, and frequency of ACD caused by therapeutic skincare products were evaluated., Results: In all, 23 (88.5%) patients reacted to at least one allergen, 21 (80.7%) had a relevant positive patch test, and 15 (57.7%) were polysensitized. The main positive sensitizers were nickel (38.5%), blue disperse (30.8%), fragrance mix (30.8%), and neomycin (23.1%). Nineteen (73%) patients reacted to substances present in therapeutic or skincare products., Conclusion: Our data underscore the importance of performing a PT in AD children whose eczema has atypical distribution. The expressive percentage of positive tests, especially of allergens in skincare products, indicates the constant need to review the proposed treatments. Therefore, we recommend a specific and expanded PT battery for pediatric AD patients, including a negative control, to increase sensitivity for diagnosing ACD., Competing Interests: The authors declare no potential conflicts of interest regarding this article's research, authorship, and/or publication.

Background: Allergic contact Dermatitis® (ACD) in older adults (OA) represents a significant health burden, but few studies examine the prevalence and characteristics of contact allergy and ACD in this population. Objective: To compare positive and clinically relevant patch test results in OA versus younger adults (YA) and children. Methods: Retrospective analysis of patch test results obtained in OA (≥65 years), YA (19-64 years), and children (≤18 years) by the North American Contact Dermatitis® Group, 2009 to 2020. Results: Of 28,177 patients patch tested, 5366 (19.0%) were OA. OA were more likely to have a final primary diagnosis of ACD as compared with YA (50.8% vs 49.2%, P  = 0.035) and children (44.6%, P  < 0.0001). The primary site of Dermatitis® also differed by age group, with OA having a higher proportion of Dermatitis® affecting the trunk, scalp, anogenital region, and "under clothing," and a lower proportion of Dermatitis® affecting the face, lips, and feet. Limitations: Retrospective design, lack of follow-up, and referral population. Conclusion: OA were as likely and were statistically even more likely to have a final primary diagnosis of ACD compared with YA and children. Anatomic site of Dermatitis® also differed by age group. This underscores the need for patch testing in OA when ACD is suspected.

Background: Many people live with ostomies after life-saving surgery. Ostomy patients often suffer from peristomal dermatitis. Allergic contact dermatitis (ACD) has been reported, mostly due to contact allergy (CA) to topical agents., Objectives: We present three patients with therapy resistant peristomal dermatitis, suggesting ACD caused by different stoma products., Methods: Patch testing was performed with baseline series, additional series, and selected allergens. They were also tested with their own ostomy products as is and separate extracts of the products. Extracts were analysed using Gas Chromatography-Mass Spectrometry (GC-MS)., Results: In all three patients we diagnosed CA to 1,6-hexanediol diacrylate (HDDA), +++ in case (C) 1 and 3, ++ in C 2. HDDA was detected in C 2's ostomy pouch adhesive and in C 1's and 3's flange extenders used to improve the adhesion of the ostomy pouches., Conclusion: Therapy resistant peristomal dermatitis should always be suspected of ACD and patch testing, especially with the patient's own products, should be performed., (© 2024 The Authors. Contact Dermatitis published by John Wiley & Sons Ltd.)

Background: Distinguishing between allergic and nonallergic forms of Contact Dermatitis (CD) is challenging and requires investigations based on patch-testing. Early detection of allergy biomarkers in active CD lesions could refine and simplify the management of CD patients., Objective: To characterize the molecular signatures of active CD lesions., Methods: We studied the expression of 12 allergy biomarkers by qRT-PCR in active lesions of 38 CD patients. Allergic CD (ACD) was diagnosed based on patch test (PT) results and exposure assessment. Molecular signatures of active lesions, as well as positive PT reactions, were compared with those of reference chemical allergens and irritants., Results: Nineteen of the 38 CD patients reacted positively upon patch-testing and exposure assessment confirmed ACD diagnosis for 17 of them. Gene profiling of active CD lesions revealed 2 distinct molecular patterns: patients harboring signatures similar to reference allergens (n = 23) or irritants (n = 15). Among the 23 patients with an "allergy signature," we found the 17 patients with confirmed ACD, while no culprit allergen was identified for the 6 other patients. Interestingly, the 15 patients without biomarker induction had negative PT, suggesting that they developed nonallergic CD reactions., Conclusion: Molecular signatures from active skin lesions may help to stratify CD patients and predict those suffering from ACD., Competing Interests: Conflicts of interest None disclosed., (Copyright © 2024 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.)

Background: The relationship between atopic dermatitis (AD) and allergic contact dermatitis (ACD) is a matter of debate., Objectives: The purpose of our study is to assess the frequency of ACD in patients with AD, the incriminated allergens and the potential risk factors., Methods: This is a prospective study, including cases of AD diagnosed based on Hanifin and Rajka's criteria. All patients were patch tested to the European baseline series and corticosteroid series., Results: Ninety-three patients were included. Fifty-six patients (60.2%) had positive patch test results of which 71.4% were relevant. The most frequent allergens were: textile dye mix (24.7%), nickel (20.4%), cobalt (12.9%), isothiazolinone (8.6%), quanterium 15 (4.3%) and balsam of Peru (4.3%). Chromium, fragrance mix I, fragrance mix II and PTBP were positive in three cases (3.2%). Two cases of allergy to corticoids were identified. Facial involvement and duration of AD were significantly associated with contact sensitization (p = 0.04 and p = 0.005, respectively). Avoidance of relevant allergens resulted in a statistically significant decrease in SCORAD (p < 0.001)., Conclusions: ACD remains an important co-morbidity of AD. We observed a high frequency of ACD to textile dyes, isothiazolinones and fragrances. Avoidance of relevant allergens has resulted in an improvement of patients' skin symptoms., (© 2023 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Introduction: Allergic contact dermatitis (ACD) is a common cutaneous inflammatory skin disorder that is diagnosed via epicutaneous patch testing (PT). ACD may also coexist with other systemic inflammatory conditions such as atopic dermatitis and psoriasis. Many of the treatments used to manage severe ACD, along with other systemic conditions, interact with and suppress the immune system, thereby potentially interfering with the mechanism of PT. There is uncertainty in the literature regarding the effects of immunosuppression on the results of PT., Methods: A comprehensive literature review was conducted using PubMed and Google Scholar to identify articles relevant to the topic of this review. Only articles available in English were included., Areas Covered: This review discusses the impact of immunomodulating therapies on the results of PT. We summarize the available evidence and provide updated recommendations for several immunomodulating drugs commonly used in patients undergoing PT., Expert Opinion: In general, the results of PT are most reliable when performed without immunosuppression. If this is not feasible, it is best to have patients on as low a dose of immunosuppression as possible, but it may not be necessary to stop or change an immunomodulating drug prior to PT.

Background: 2-Hydroxyethyl methacrylate (HEMA) was added to the European baseline series (EBS) in 2019. Few recent data are available on the frequency and relevance of positive reactions to this hapten., Objectives: To investigate the frequency and relevance of positive patch tests to HEMA in the EBS in a university hospital in Amsterdam, The Netherlands., Patients and Methods: Retrospective study in patients with positive patch tests to HEMA investigated between June 2019 and August 2023., Results: Of 2927 consecutive patients, 88 (79 women and 9 men; 3.0%) had a positive reaction to HEMA. The prevalence in women was 3.9%, in men 1.0%. Forty-three (49%) reactions were judged to be of current clinical relevance and 21 (24%) of past relevance. In this group of 64 patients with relevant reactions, 18 (28%) had occupational contact with (meth)acrylate-containing products, of who 11 (61%) were nail stylists. In 46 patients with non-occupational allergic contact dermatitis, 31 (67%) had allergic reactions to nail cosmetics. Glues and glue-containing products accounted for 22% of the materials causing allergic contact dermatitis and dental products for 8%., Conclusions: Allergic reactions to HEMA are very frequent in women investigated in Amsterdam. Nearly two thirds of cases were caused by nail cosmetics., (© 2023 The Authors. Contact Dermatitis published by John Wiley & Sons Ltd.)

Allergic contact dermatitis (ACD) is a common inflammatory skin disease caused by delayed hypersensitivity to chemical and biotic contact allergens. ACD significantly affects the patients' quality of life negatively impacting both occupational and non-occupational settings. Patch testing is the gold standard diagnostic in vivo test to precise the ACD etiology and to correctly perform prevention. According to the Italian Medicines Agency (AIFA) legislative decree no. 178 of 29 th May 1991, allergens are defined as medicines and therefore they are subject to strict regulation. In 2017, AIFA (decree no. 2130/2017) started a procedure to regulate contact allergens on the Italian market and actually the contact allergens temporarily authorized are reported in AIFA decree no. 98/2022, valid until November 2023. The availability on the market of contact allergens to diagnose ACD and continuous updating on the basis of new epidemiological trends are mandatory, jointly with the continuous update of the baseline and integrative series for patch testing. For this reason, the scientific community represented in Italy by the Skin Allergies Study Group of SIDeMaST (Italian Society of Dermatology and Venereology) and SIDAPA (Italian Society of Allergological, Occupational and Environmental Dermatology) are constantly working, in close relationship with the European scientific communities with large expertise in this important sector of the modern Dermatology. Herein, we report the setting up of regulatory legislation by AIFA and the new Italian Adult Baseline Series for patch testing.

Background: Due to limited availability of commercial test preparations, patch testing patient's own material (POM) is of great importance to diagnose occupational allergic contact dermatitis., Objectives: To assess the quality of performance and documentation of patch testing with POM in patients with suspected occupational skin diseases (OSD) in Germany., Methods: Retrospective-prospective analysis of protocols of patch tests with POM was conducted between 2013 and 2021 in patients with suspected OSD and submitted to statutory accident insurance institutions. Assessments were done by predefined criteria., Results: Three thousand and four patch tests with POM from 460 patients were included. A full description of the POM was provided in 73.3% of all tests. The test concentration, test vehicle and pH value were documented in 74.3%, 70.5% and 42.2% of tests, for which the respective parameters were considered relevant. One hundred and sixty-one positive reactions to POM were documented. In 72%, sufficient patch testing with commercial test substances was conducted to investigate the positive reaction. In 30.4%, consecutive patch testing of all ingredients of the POM was done., Conclusions: The results not only show considerable shortcomings mainly in documentation but also to some extent performance of patch tests with POM in patients with suspected OSD in Germany., (© 2023 The Authors. Contact Dermatitis published by John Wiley & Sons Ltd.)

Background: Artificial nail materials are mixtures that are prone to contain several sensitizing (meth)acrylates. It is not known whether the listing of (meth)acrylates is correct in these products' packages. Protective gloves suited for nail work are needed., Objectives: To analyse (meth)acrylates in gel nail and acrylic nail products chemically and to compare the results with the information in the product labels, and to study penetration of artificial nail materials through selected disposable gloves., Methods: We analysed 31 gel nail products and 6 acrylic nail products for their (meth)acrylate content by gas chromatography-mass spectrometry (GC-MS). We tested the penetration of two nail products through three disposable gloves: nitrile rubber, neoprene rubber and polyvinyl chloride (PVC)., Results: Altogether 32/37 products contained (meth)acrylates. In all of them, there was discrepancy between the listed (meth)acrylates and those discovered in the analysis. The commonest (meth)acrylates were hydroxyethyl methacrylate (HEMA, 20/37 samples) and hydroxypropyl methacrylate (HPMA, 9/37 samples), but many of the product packages failed to declare them. Isobornyl acrylate (IBA) was discovered in nine gel nail products. The neoprene glove could withstand nail gel for 20 min and thin nitrile glove and PVC glove for 5 min. Acrylic nail liquid penetrated through disposable gloves quickly., Conclusions: Labelling of artificial nail products was notably incorrect on most products. Requirements for product labelling must be updated so that the risk of sensitization associated with artificial nail products is clearly indicated. Disposable gloves can probably be used short-term in gel nail work, whereas disposable gloves do not protect the user from acrylic nail liquids., (© 2023 The Authors. Contact Dermatitis published by John Wiley & Sons Ltd.)

Background: Over the last 10 years, allergic contact dermatitis (ACD) from acrylate-containing nail cosmetics (acrylic nails, gel nails, gel nail polish) has been reported repeatedly., Objectives: To investigate the frequency and clinical features of ACD in nail cosmetics in a university hospital in Amsterdam, The Netherlands., Patients and Methods: A retrospective study in patients diagnosed with ACD from acrylate-containing nail cosmetics at the Amsterdam University Medical Centers between January 2015 and August 2023., Results: Sixty-seven patients, all women, were diagnosed with ACD from nail cosmetics, representing 1.6% of all individuals and 2.3% of all women patch tested in this period. Sixty-five of sixty-seven (97%) subjects had a positive patch test to 2-hydroxyethyl methacrylate (HEMA). Forty-nine patients (73%) were consumers and 18 (27%) were professional nail stylists. The sites most frequently affected with dermatitis were the fingers (79%), hands (40%) and the head and/or neck. Avoidance of contact with acrylate-containing products resulted in complete clearing of dermatitis in 80% of patients., Conclusions: ACD from acrylate-containing nail cosmetics is frequent in women patch tested in Amsterdam. Nearly all were identified by a positive patch test to 2-hydroxyethyl methacrylate in the (meth)acrylate series or the European baseline series., (© 2023 The Authors. Contact Dermatitis published by John Wiley & Sons Ltd.)

Background: The growing popularity of nail techniques based on acrylates has led to a higher frequency of sensitization in both nail technicians and users., Objectives: The study aimed to assess cases of allergic contact dermatitis (ACD) caused by acrylates in individuals with occupational or non-occupational exposure to nail techniques., Methods: A preliminary study was conducted on 30 patients with ACD caused by acrylates in nail techniques, who were patch tested from September 2022 to March 2023 at the First Department of Dermatology and Venereology of Andreas Syggros Hospital, Athens, Greece., Results: Thirty female patients with ACD to acrylates were documented (15 users and 15 nail technicians and users). The most common allergens were: 2-hydroxyethyl methacrylate (HEMA), 2-hydroxypropyl methacrylate (HPMA) and ethyleneglycol dimethacrylate (EGDMA), which tested positive in all 30 patients (100.0%). Twenty patients (66.7%) had been exposed to dental procedures involving acrylates, before the onset of ACD. Nail technicians exhibited extensive skin lesions, 40.0% experienced ACD within the first year of work and 13.3% during their professional practice. Three of them (20.0%) had to discontinue their work., Conclusion: Acrylates have been identified as potent allergens, necessitating the implementation of safety measures for the use of these chemicals in nail techniques., (© 2024 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: Limited and conflicting data have been reported on the impact of dupilumab (DUPI) on patch test (PT) results and its efficacy against allergic contact dermatitis (ACD)., Objective: This study was undertaken to analyze PT reactivities and relevance during treatment with DUPI to determine whether they could detect ACD in patients with uncontrolled or worsened atopic dermatitis (AD) who were receiving this agent., Methods: This prospective, multicenter study examined 76 DUPI-treated patients who had undergone PTs. The relevant information was collected during 3 visits., Results: Overall, 36 patients (47%) had ≥1 positive PT reaction, and 142 PT results were positive. Twenty-three patients (30%) had ≥1 positive and clinically relevant PT result. Five of them had clinical eczema improvement after allergen avoidance. We compared the PT results of 36 patients before and during DUPI therapy, representing 1230 paired PT allergens, of which 1022 were the same, 34 were positive, 44 were lost, and 130 were uninterpretable., Limitations: Because the number of patients included remains limited, our findings should be confirmed with a larger sample., Conclusion: Our results confirmed the usefulness of PTs for patients receiving DUPI, with good PT reproducibility. We suggest that all DUPI-treated patients with AD developing partial responses or experiencing symptom worsening should undergo PTs to look for contact sensitization., Competing Interests: Conflicts of interest Author Soria has received honoraria for advisory boards from Sanofi and was a speaker at a meeting organized by Sanofi. Dr Raison-Peyron has received honoraria for personal fees from Sanofi. Dr Badaoui has received honoraria for conferences and for advisory boards from Sanofi. Dr Marcant was a speaker at a meeting organized by Sanofi. Dr Bara has received honoraria for expert for a round table by Sanofi. Dr Giordano-Labadie has received honoraria for advisory boards from Sanofi. Dr Amsler has received honoraria for conferences and was a speaker at a meeting organized by Sanofi. Dr Delaunay has received honoraria for advisory boards from Sanofi. Dr Pralong has received honoraria for advisory boards from Sanofi. Dr Boulard was a speaker at a meeting organized by Sanofi and has received honoraria for advisory boards, study from Sanofi. Dr Ferrier Le Bouedec has received honoraria for expert for a round table by Sanofi. Author Tauber has received honoraria from Sanofi. Dr Pasteur has received honoraria for advisory boards from Sanofi and speaker at scientific meetings by Sanofi. Dr Valois has received honoraria for advisory boards from Sanofi and was a speaker at a meeting organized by Sanofi. Dr Crépy reports being an investigator, a consultant, and a speaker for Sanofi. Dr Bernier has received honoraria for advisory boards from Sanofi., (Copyright © 2023 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.)

Only few studies on contact allergy in African countries have been published. The aim of the present study was to provide an overview of the most common contact allergens identified by the use of patch tests in African countries based on a review of the existing literature. A total of twenty-four publications from eight African countries were initially identified by search in PubMed. The abstracts and method sections were screened, and 15 studies in which patch tests were actually used to identify the allergen causing the allergic contact dermatitis (ACD) were finally selected. Nickel, cobalt, chromium, fragrance mix and p-tert-butylphenol-formaldehyde resin were the dominating contact allergens responsible for 40%-90% of the positive patch test reactions. This study indicates that a targeted effort directed towards prevention, avoidance and regulation of reliably identified contact allergens could reduce the disease burden of ACD considerable in some African countries., (© 2023 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: Preservatives are a frequent cause of allergic contact dermatitis (ACD) and have caused numerous epidemics., Objectives: The objective of this study is to determine the prevalence of preservative sensitivity, assess the change in the frequency of sensitivity, identify new preservatives with increased sensitivity rates, and evaluate the situation in Turkey by comparing our findings with current literature., Methods: A total of 201 patients diagnosed with ACD between 2018 and 2020, were patch tested with the European baseline series and additional seven preservative haptens. The change in the prevalence of sensitivity to each preservative hapten was investigated by comparing the data from the study conducted in our department between 2000 and 2004., Results: Results showed that 17.4% (n = 35) of the patients were positive to preservatives. Comparison with previous data from 2000 to 2004 revealed an increase in the frequency of sensitization. The most prevalent allergen was methyldibromo glutaronitrile (9.5%), followed by methylchloroisothiazolinone/methylisothiazolinone (6.5%), and methylisothiazolinone (5%)., Conclusion: The increase in preservative sensitivity in Turkey is the most remarkable finding. Although MDBGN was prohibited in cosmetic products, MCI/MI and MI are still widely used. Our findings suggest that awareness of preservative sensitivity should be increased and additional precautions should be taken, also in Turkey, regarding the use of preservatives., (© 2023 The Authors. Contact Dermatitis published by John Wiley & Sons Ltd.)

Summary: Background. Atopic dermatitis is a prevalent condition in the pediatric population, with affected children exhibiting a susceptibility to cutaneous sensitization due to skin barrier dysfunction and immune dysregulation. Recent studies have highlighted an increased prevalence of certain allergens, which identifi-cation may be clinically relevant, with direct implications for the management of atopic dermatitis. Methods. We retrospective reviewed pediatric patients patch tested due to suspected contact dermatitis. Patients were divided according the diagnosis of AD, with subsequent comparison of positive results for both groups. Results. A total of 145 pediatric patch testing were analyzed, 44.1% (n = 63) with the diagnosis of atopic dermatitis. There were notable differences in sensitization rates of relevant allergens between groups and when compared to other European studies. Based on the most prevalent and relevant allergens, we proposed an adapted hapten series for assessing portuguese pediatric patients with AD and suspicion of concomitant allergic contact dermatitis. Conclusions. Our findings confirmed the geograph-ic sensitization variability and emphasize the need for pediatric adaptation and "individualized baseline series".

Latex allergy is a hypersensitivity response to natural rubber latex (NRL) proteins or rubber chemicals used in the manufacture of latex products. An accurate diagnosis is the first step in the effective management of individuals with latex allergy, especially in high-risk groups, such as healthcare workers and those affected by spina bifida. Diagnosis is based on the clinical history and an accurate allergological evaluation. In the case of type I IgE-mediated hypersensitivity reactions, which can manifest urticaria, angioedema, rhinoconjunctivitis, asthma and anaphylaxis after latex exposure, skin prick tests or latex-specific IgE (sIgE) antibody detection using serological assays can be performed to confirm sensitization. Instead, in the case of contact dermatitis, a patch test can be applied to confirm the presence of a type IV T cell-mediated hypersensitivity reaction to rubber accelerators or additives. Basophils activation tests or challenge tests may be performed if there's an incongruity between the clinical history and the results of in vivo and in vitro tests. The aim of this review is to analyze the current state of the art of diagnostic techniques for latex allergy and algorithms employed in clinical practice and possible future developments in this field., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Background: Botanicals are increasingly incorporated into skincare products. Although allergic contact dermatitis due to botanicals is recognized, data describing the prevalence of positive patch tests to botanicals are sparse. Objective: To report the Mayo Clinic experience of patch testing to selected botanical products in the standard, extended standard, fragrance, and plant series. Methods: IRB-approved retrospective study of the Mayo Clinic experience with patch testing to botanicals from 1997 to 2017. Results: In total, 12,169 people were patch tested to botanicals in the standard, extended standard, fragrance, and plant series; 4032 were men and 8137 were women. The mean age of the population tested was 54 (standard deviation 17.7) years. Almost 11% (1320/12,169) of the patch-tested population exhibited positive reactions to at least 1 botanical agent. Myroxylon pereirae resin 25% was the most common positive allergen in the series. Patients who had positive reactions to at least 1 botanical agent were more (19.8%) likely to have a positive reaction to at least 1 additional botanical than those patients who did not have any positive tests. Most patients presented with generalized involvement (334) or involvement of the hands (284) or face (232). Conclusion: Physicians should be aware of the high prevalence of allergic contact dermatitis and patch test positivity associated with botanical products.

This is the second part of a literature review of the clinical aspects of contact allergy to and allergic contact dermatitis from 2-hydroxyethyl methacrylate (HEMA). Topics include cross- and co-sensitization, atypical manifestations of contact allergy, frequency of positive patch tests to HEMA compared with other (meth)acrylates, sensitivity of HEMA as a screening agent, the presence of HEMA in commercial products, and practical information on patch testing procedures. Primary sensitization to methacrylates including HEMA may result in methacrylate and acrylate cross-sensitization. There is a strong cross-allergy between HEMA, ethylene glycol dimethacrylate (EGDMA), and hydroxypropyl methacrylate; many reactions to EGDMA are cross-reactions to primary HEMA sensitization. Rare atypical manifestations of HEMA-allergy include lichen planus, lymphomatoid papulosis, systemic contact dermatitis, leukoderma after positive patch tests, and systemic side effects such as nausea, diarrhoea, malaise, and palpitations. The occurrence of respiratory disease caused by methacrylates such as asthma is not infrequent. HEMA is the most frequently patch test-positive methacrylate. It is a good screening agent for allergy to other (meth)acrylates. Patch test sensitization to HEMA 2% pet. is extremely rare. There are (some) indications that HEMA is frequently used in dental products and nail cosmetics., (© 2023 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: While many studies have reported on occupational allergic contact dermatitis amongst dental personnel, studies on the relevance of patch testing in dental patients are scarce., Objectives: To determine the frequency and clinical relevance of contact allergy in patients with intra- and perioral complaints., Methods: A total of 360 patients with intra- and perioral complaints suspected of having a contact allergy were patch-tested with the dental allergen series, European Baseline Series, and extended Amsterdam Baseline Series at Amsterdam University Medical Centers between January 2015 and November 2021., Results: A total of 285 patients (79.2%) had a positive patch test reaction for either one (18.6%) or multiple allergens (60.6%). Sodium tetrachloropalladate was the most sensitising allergen with 98 patients (27.2%) testing positive, followed by nickel sulphate (23.3%), methylisothiazolinone (15.6%), and fragrance mix I (14.2%). Clinical relevance was found in 68 of 208 patients (32.7%), with patients having one (15.4%) or multiple (17.3%) patch test reactions clinically relevant to their (peri)oral complaints., Conclusions: Clinically relevant patch test reactions were frequently seen in dental patients. Although this study provides us with a better understanding on the frequency and clinical relevance of contact allergy in dental patients, further studies are needed to confirm our results., (© 2023 The Authors. Contact Dermatitis published by John Wiley & Sons Ltd.)

Medical adhesive tapes are commonly recommended for the prevention of friction blisters during hiking and military marches. The aim of this paper is to report on the results of investigations into an outbreak of tape-related foot dermatitis in 26 military conscripts following continuous use of medical adhesive tapes for several days during a field exercise. Patch tests were performed using baseline series and aimed testing was performed with colophonium-related substances and different medical adhesive tapes. Contact allergy to the adhesive tapes used was found in 20 (77%) subjects, and contact allergy to colophonium in 16 (61%). Chemical analysis detected colophonium-related substances in the culprit tapes. Compared with consecutive dermatitis patients investigated at our Department of Occupational and Environmental Dermatology in the previous 10 years, conscripts with colophonium allergy had increased odds ratios for concomitant contact allergy to phenol formaldehyde resins and fragrance substances including hydroperoxides of limonene and linalool. The results show that prolonged use of medical adhesive tapes on intact skin carries a high risk for allergic contact dermatitis. Prior to their introduction on the market, medical devices should be assessed for possible side-effects.

2-Hydroxyethyl methacrylate (HEMA) has been increasingly recognised as a contact allergen and was added to the European baseline series in 2019. In this article (2 parts), the results of an extensive literature review of the clinical aspects of contact allergy/allergic contact dermatitis to HEMA are presented. In part 1, the epidemiology of HEMA contact allergy is discussed and detailed information on published case series and case reports presented. HEMA is an important cause of contact allergy/allergic contact dermatitis in North America and Europe with recent prevalences of >3% in the USA + Canada and 1.5%-3.7% in Europe. Currently, most cases are caused by nail cosmetics, both in consumers and professional nail stylists. In our literature review, we have found 24 studies presenting case series of patients with allergic contact dermatitis attributed to HEMA and 168 case reports. However, the presence of HEMA in the products causing ACD was established in only a minority. Part 2 will discuss cross- and co-sensitisation, and other skin reactions to HEMA, will assess whether HEMA is the most frequent (meth)acrylate allergen and how sensitive HEMA as a screening agent is, investigate the presence of HEMA in commercial products and provide practical information on patch testing procedures., (© 2023 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: Patch testing is gold standard for identifying the source of allergic contact dermatitis (ACD). Objective: To report patch testing results from the Massachusetts General Hospital (MGH) Occupational and Contact Dermatitis Clinic from 2017 to 2022. Methods: Retrospective analysis of patients referred to MGH for patch testing, 2017-2022. Results: In total, 1438 patients were included. At least 1 positive patch test (PPT) reaction was observed in 1168 (81.2%) patients and at least 1 relevant PPT reaction was observed in 1087 (75.6%) patients. The most common allergen with a PPT was nickel (21.5%), followed by hydroperoxides of linalool (20.4%) and balsam of Peru (11.5%). Sensitization rates statistically increased over time for propylene glycol and decreased for 12 other allergens (all P values <0.0004). Limitations: Retrospective design, single institution tertiary referral population, and variations in allergens and suppliers across the study period. Conclusion: The field of ACD is constantly evolving. Regular analysis of patch test data is crucial to identify emerging and diminishing contact allergen trends.

Background: Identification of athletic shoes for patients with contact allergy is difficult. Company reports of allergen content are often incorrect. Objectives: To determine whether chemical analysis of 4 athletic shoes, previously reported to be free of the most common contact allergens, contain quantifiable allergen levels. Methods: Samples from the uppers and insoles of 4 shoes believed to be free of common allergens were assessed by mass spectrometry. A total of 4 rubber accelerators and 2 adhesives were directly quantified and additional 7 rubber accelerators were assessed using semiquantitative measures. Results: Aside from carbamates (assayed as 59 ppm zinc in insoles) in SeaVee's Sixty-Six sneakers, para-tertiarybutylphenol formaldehyde resin (PTBFR) (assayed as 7.6 ppm paratertiary butylphenol or 4-tertiary butylphenol [4TBP] in uppers) in Allbirds Tree Runners and rosin (assayed as 628 ppm sodium abietate in uppers) and carbamates (24 ppm zinc in uppers) in Saucony Jazz sneakers, these shoes had low levels of all allergens assayed in this study. Tom's Carlo sneakers contained rosin (127 ppm sodium abietate in insoles), PTBFR (6.5 ppm 4TBP in uppers), and carbamates (112 ppm sodium abietate in insoles) but had low levels of all other assayed allergens. Conclusions: Although identifying allergen-free shoes is challenging, the results of this analysis will help patch testing physicians recommend athletic shoes to patients with specific allergies.

Background: A high incidence of local itching subcutaneous nodules and aluminium allergy was observed in clinical trials of a new aluminium adsorbed pertussis vaccine in Gothenburg, Sweden, in the 1990s. A total of 495 children with itching nodules were patch tested with aluminium chloride hexahydrate 2% and an empty Finn Chamber®, 377 (76%) with positive reactions. When 241 of them were re-tested some years later 186 (3 out of 4) had unexpectedly lost their patch test reactivity., Aim: To investigate the long-term prognosis of vaccine-induced contact allergy to aluminium by a third patch test about 20 years after Patch test I., Methods: Twenty individuals with positive and 11 with negative results in Patch test II were tested a third time with the same sensitisers as in in the first two tests. Three additional aluminium preparations were also tested., Results: A total 15 out of 20 persons with positive results in the second test had lost their patch test reactivity. Two of 11 with negative tests had turned positive again. The addition of the preparations gave no conclusive results., Conclusion: Contact allergy to aluminium caused by vaccination with aluminium-adsorbed vaccines in childhood seems to fade away with time as measured by loss of patch test reactivity., (© 2023 The Authors. Contact Dermatitis published by John Wiley & Sons Ltd.)

Background: Allergens responsible for allergic contact dermatitis (ACD) differ between populations. They can even change over the years with the effect of environmental factors., Aims: To evaluate the results of patch testing performed in our center., Methods: In this study, the thin-layer rapid-use epicutaneous (T.R.U.E.) test results of patients with a diagnosis of ACD between 2012 and 2022 were retrospectively evaluated., Results: In 431 (42.5%) of the total 1012 patients, a positive reaction to at least one allergen was detected in the patch test. Allergen positivity was most detected for nickel sulphate (16.8%), gold sodium thiosulfate (GST) (6.9%), thimerosal (4.2%), fragrance mix (3.4%), carba mix (3.2%), and cobalt dichloride (2.9%). Nickel sulfate and GST sensitivity was found to be significantly higher in women, fragrance mix sensitivity in men, thimerosal sensitivity in individuals aged under 40 years, colophony and balsam of Peru sensitivity in head and neck dermatitis, and carba mix and thiuram mix sensitivity in atopic individuals., Conclusions: This study presents comprehensive data from Turkey concerning the sensitivity frequencies for allergens included in the T.R.U.E. test., (© 2023 The Author. Journal of Cosmetic Dermatology published by Wiley Periodicals LLC.)

Background: Although allergic contact dermatitis (ACD) is relatively common in the adult and pediatric populations alike, few studies describe the special features of contact sensitization among the Israeli pediatric populations, none of them is multicenter. Our study aims to describe and analyze patch test results and trends in 4 tertiary care centers between 2012 and 2022. Methods: We assessed the results of 357 patch tests performed on children 0-18 years old between 2012 and 2022 in designated clinics in 4 tertiary medical centers. All patients were tested using the European baseline series and additional series as clinically indicated. We assessed the demographic features, atopic features, and influence, as well as the main allergens to cause sensitization and allergic contact dermatitis among the pediatric population. Results: In total 69% of the study population were females, mainly 12-18 years old, 35% of the study population were previously diagnosed with atopic dermatitis, and 57% had an atopic diathesis. Females were more commonly sensitized ( P  < 0.05). Patients without atopic dermatitis were more commonly diagnosed with ACD and had more reactions on patch test ( P  < 0.05). The most common allergens to cause ACD are preservatives and metals, as previously described, however, acrylate sensitivity is an emerging group that has not been described among the Israeli pediatric population in previous studies. Fragrance mix 2 and Mroxylon pereirae are relatively rare allergens among the Israeli pediatric population, whereas linalool hyperoxide might be considered an emerging allergen. Methylisothiazolinone causes ACD more frequently among patients without atopic dermatitis ( P  < 0.05). Conclusions: Among the Israeli pediatric population, ACD is more common in females without atopic dermatitis. Acrylates become a common culprit and should be included in baseline series. Patients with atopic dermatitis are less frequently sensitized by methylisothiazolinone.