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Background: Atopic dermatitis (AD) and allergic contact dermatitis (ACD) are inflammatory skin conditions whose association is not clearly defined., Objectives: To identify differences in ACD profile between patients with and without AD among those referred for patch testing. Additionally, to determine the prevalence of sensitisation to standard Spanish contact allergens in both groups., Methods: We analysed two groups (AD and non-AD) within the Spanish Registry of Research in Contact Dermatitis and Cutaneous Allergy (REIDAC). Contact allergy, clinical relevance and epidemiological data were compared between them., Results: A total of 5055 patients were included. Among them, 23% (1168) had a history or final diagnosis of AD. At least one positive reaction was seen in 468 (40%) of AD patients and 1864 (48%) of non-AD patients. In both groups, the most common positive reactions were to nickel sulphate, methylchloroisothiazolinone/methylisothiazolinone and cobalt chloride. Age-adjusted OR for sensitisation to nickel sulphate was 0.72 (95% CI: 0.61-0.86), indicating a decreased likelihood of sensitisation in AD patients compared to non-AD individuals., Conclusions: We did not find an increased presence of ACD in patients with AD referred for patch testing, exhibiting similar profiles to non-AD population, except for a negative relationship between AD and sensitisation to nickel sulphate., (© 2024 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: Reports of allergic contact dermatitis (ACD) to phytonadione epoxide (PE) in cosmetics suggest that PE is as powerful a sensitiser as its parent compound phytonadione., Objective: To evaluate a case series of ACD to PE in Spain., Methods: We reviewed the records of 20 patients with ACD to cosmetics containing PE diagnosed across Spain between January 2019 and June 2023., Results: All 20 patients developed patch test (PT) or repeated open application test (ROAT) reactions to cosmetics containing PE. All involved women with eyelid eczema. PT or ROAT with PE preparations were positive in 17/20 (85%). PE at 1%, 5%, 10% and 20% in pet. was patch-tested in 8/17, 14/17, 11/17 and 8/17 patients; being positive in 6/8 (75%), 13/14 (92.85%), 11/11 (100%) and 8/8 (100%), respectively., Conclusion: Regulators should, not only ban the specific dangerous cosmetic ingredients, but also consider to ban or keep under close surveillance those closely related products or derivatives that might potentially cause similar harmful effects. PTs with PE are suggested to be performed at a 5% concentration in pet. Higher concentrations (10% pet.) should be tested whenever PTs with 5% pet. PE are negative., (© 2024 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: A global epidemic of allergic contact dermatitis to (meth)acrylates has been described in relation to the widespread use of manicure products., Objectives: To evaluate the frequency of sensitization to 2-hydroxyethyl methacrylate (2-HEMA) among consecutively patch tested patients with eczema in Spain; the percentage of current relevance; the MOAHLFA index; and, the potential sources of exposure to (meth)acrylates., Methods: From January 2019 to December 2022, 2-HEMA 2% pet. was prospectively patch tested in 24 REIDAC (Spanish Allergic Contact Dermatitis Registry) centres., Results: Six thousand one hundred thirty-four patients were consecutively patch tested with 2-HEMA 2% pet. 265/6134 (4.3%) were positive. Positive reactions of current relevance were identified to involve 184/265 (69%). The efficiency (number of patch tests needed to detect relevant positive patch test reactions) was 34 (6134/184). The variable 'occupational' was found to be significantly associated with a higher risk for relevant positive reactions to 2-HEMA (OR: 10.9; 95% CI: 8.1-14.9)., Conclusion: (Meth)acrylate sensitization is a prevalent health issue in Spain. 2-HEMA 2% pet. has been identified to be a highly effective (meth)acrylate allergy marker in the GEIDAC baseline series. The responsible authorities should implement policies guaranteeing accurate labelling of industrial, medical, and consumer materials while ensuring the enforcement of said labelling through appropriate legal means., (© 2024 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: There is speculation that some environmental factors may be impacting the increasing incidence of frontal fibrosing alopecia (FFA). In a recent publication, sensitisation to benzyl salicylate was shown to be prevalent among 36 patients with FFA. Ethylhexyl salicylate (EHS), a light stabiliser, ultraviolet (UV) B absorber and UV filter, frequently found in photoprotectors/cosmetics and, rarely reported as a sensitiser, was not patch tested in said research., Methods: From January 2021 to February 2022, 33 patients with FFA were patch-tested with the European Photopatch Series, including EHS 10% pet. in two hospitals. In addition, we conducted a literature review and a market survey., Results: Patch test reactions to EHS were identified in 9 of 33 (27.3%). Four of nine also reacted to their personal sunscreens (containing EHS). All involved women with a mean age of 54 (30-65). Five patients had been diagnosed with FFA before the patch tests; and, four were diagnosed with FFA during the patch test investigations., Conclusion: Sensitisation to EHS was frequently found in a selected population of patients with FFA. We propose to expand the spectrum of contact allergens described in patients with FFA to include EHS and discuss the possible need for optimization of the patch test preparation., (© 2023 The Authors. Contact Dermatitis published by John Wiley & Sons Ltd.)

Background: Budesonide and tixocortol pivalate as markers of contact allergy to corticosteroids have been questioned, as they are not able to detect a significant percentage of allergic patients., Objectives: To investigate the potential role of clobetasol propionate in enhancing corticosteroid sensitisation detection., Methods: Between January 2022 and December 2023, patients who attended centres involved in the Spanish Registry of Research in Contact Dermatitis and Cutaneous Allergy were tested with an extended baseline series that included budesonide, tixocortol pivalate, clobetasol propionate 0.1% in ethanol and 1% in petrolatum., Results: A total of 4338 patients were tested. Twenty-four patients were allergic to budesonide (0.55%, 95% CI: 0.37-0.82); nine patients were allergic to tixocortol pivalate (0.21%, 95% CI: 0.11-0.39); and 23 patients were allergic to clobetasol (0.53%, 95% CI: 0.35-0.79). Only four of those patients allergic to clobetasol were detected by budesonide and one by tixocortol pivalate. No significant differences in the number of positive tests were found between clobetasol in petrolatum or ethanol., Conclusions: In Spain budesonide remains the main corticosteroid allergy marker whereas the role of tixocortol pivalate is questionable. The addition of clobetasol propionate to the Spanish baseline series would improve the ability to detect patients allergic to corticosteroids., (© 2024 The Author(s). Contact Dermatitis published by John Wiley & Sons Ltd.)

Background and Objective: Diagnosis of vibratory urticaria/angioedema is established after performing the vortex provocation test. There is current consensus on measuring the forearm perimeter after running such test to define a positive response to it., Material and Method: We evaluated the frequency of prior symptoms following vibratory stimuli in volunteers using a questionnaire, response to the vortex provocation test in the same volunteers (increase in forearm perimeter, erythema, localized edema, heat, and pruritus), interrater reliability, and correlation between the scores obtained in the questionnaire and response to the test., Results: A total of 40 volunteers participated in this survey, 17 of whom were excluded due to dermographism. A total of 59% out of 123 without dermographism responded positively to ≥ 1 items of the questionnaire. Localized erythema, heat or localized edema were reported in 58.5%, 38.2%, and 32.5%, respectively. A total of 73.6% of volunteers presented with itch. The mean intensity of itch was 3.44 (95%CI, 2.94-3.94). Interrater agreement was low regarding the increase in forearm circumference at 3 levels (intraclass correlation coefficient, 0.477 95%CI, 0.253-0.634; 0.496 95%CI, 0.280-0.647; and 0.370 95%CI, 0.100-0.559, respectively) and optimal regarding erythema, heat and localized edema (Kappa index, 0.868; .756; and .757, respectively). A significant correlation was identified between the questionnaire score and the altered response to the test in its different variables., Conclusions: We propose the following variables: erythema; localized edema; heat; and the intensity/speed of onset/duration of pruritus to define a positive response to the vortex provocation test given their ease of execution and optimal inter-observer agreement., (Copyright © 2024. Publicado por Elsevier España, S.L.U.)

Introduction: Patch test results may be influenced by age-related factors. However, there is still discordant evidence between age and patch test results., Objectives: We aim to evaluate the patch test results reflecting skin sensitisation, their relevance and association with clinical features by age group., Methods: Prospective multicentric study of all patients patch tested with the Spanish baseline series in participating centres. Age groups were pre-defined as children (0- to 11-years), adolescents (12- to 18-years), young adults (19- to 30-years), middle-aged adults (31- to 65-years) and older adults (≥66-years). Occurrence of sensitisation, relevance and clinical features were compared by age group. Factors associated with skin sensitisation were investigated with multivariate logistic regression., Results: A total of 13 368 patients were patch-tested. Differences in positive patch test results and relevance by age were detected with the highest proportion in middle-aged adults. Age-related trend differences were found for nickel, potassium dichromate, caines, colophony, Myroxylon pereirae resin, 2-hydroxyethyl methacrylate and limonene hydroperoxide. The multivariate logistic analysis (adjusted for sex, atopic dermatitis, body location and occupational dermatitis) showed an association between the age group of 31-65 (OR: 1.41, 95% CI: 1.26-1.58) and above 66-years (OR: 1.15, 95% CI: 1.01-1.32) with a higher proportion of positive results, compared with young adults., Conclusions: Positive patch test results vary according to age, with the highest occurrence in middle-aged adults. Most haptens did not present age-related differences, reinforcing the use of baseline series regardless of age., (© 2024 The Author(s). Contact Dermatitis published by John Wiley & Sons Ltd.)

Background: Allergic contact dermatitis from (meth)acrylic monomers (ACDMA) in manicure products is increasing., Objective: To evaluate the prognosis, work performance impairment and sequelae of a cohort of beauticians and manicure consumers with ACDMA sensitized from the exposure to manicure products., Methods: We conducted a telephone survey with patients diagnosed with ACDMA., Results: One hundred and six patients were evaluated, including 75 (70.8%) beauticians and 31 (29.2%) consumers. All were women with a mean age of 39 (19-62). Thirty-seven of 75 beauticians (49.3%) continued to work. Twenty-seven of 106 (25.5%) patients continued to use manicure products with (meth)acrylates regularly. Seventeen of 51 (33.3%) patients who discontinued the exposure described ongoing nail/periungual changes. Nine of 58 (15.5%) patients who required dental restoration, orthodontic or occlusal splint materials recalled reactions from them; and, 25 of 96 (26%) who used sanitary napkins recalled intolerance to them starting after the diagnosis of ACDMA. Fifteen of 25 (60%) discontinued the use of sanitary napkins., Conclusion: 49.3% beauticians continued to work; most patients stopped wearing acrylic manicure materials; reactions from dental materials were not uncommon, however, removal of dental materials was never required; and, reactions to sanitary napkins developing after the diagnosis of ACDMA were common most leading to discontinuation of use., (© 2023 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

After the meeting held by the Spanish Contact Dermatitis and Skin Allergy Research Group (GEIDAC) back in October 2021, changes were suggested to the Spanish Standard Series patch testing. Hydroxyethyl methacrylate (2% pet.), textile dye mixt (6.6% pet.), linalool hydroperoxide (1% pet.), and limonene hydroperoxide (0.3% pet.) were, then, added to the series that agreed upon in 2016. Ethyldiamine and phenoxyethanol were excluded. Methyldibromoglutaronitrile, the mixture of sesquiterpene lactones, and hydroxyisohexyl 3-cyclohexene (Lyral) were also added to the extended Spanish series of 2022., (Copyright © 2024 AEDV. Publicado por Elsevier España, S.L.U. All rights reserved.)

Background: Monitoring of adverse events induced by cosmetics performed by health authorities, known as cosmetovigilance, has been relied on the collection of case notifications., Objectives: We aimed to show how a contact dermatitis registry can contribute to the cosmetovigilance of emerging allergens. We used the example of phenylethyl resorcinol, an infrequent allergen with only 6 previous cases reported in Europe and Japan since 2013., Methods: A systematic search in the Spanish Registry of Contact Dermatitis and Cutaneous Allergy (REIDAC) database was performed to identify patients with positive patch test to phenylethyl resorcinol or cosmetics that contains it between June 2018 and January 2023. We collected the main clinical features of these patients and compared them with those of patients recorded in the registry with similar epidemiological features., Results: Thirteen patients with positive patch test to phenylethyl resorcinol were identified. All the patients were women with a mean age of 42 years (range 32-59) and their lesions were mainly in the face., Conclusion: Assessing the importance of infrequent allergens based solely on a case series is difficult. Multicentre registries facilitate the collection of cases and provide appropriate background information for new allergens., (© 2023 The Authors. Contact Dermatitis published by John Wiley & Sons Ltd.)

Background: Psoriasis is a chronic inflammatory dermatosis whose clinical and topographic distribution requires differential diagnosis, or the possible association with allergic contact dermatitis (ACD), requiring patch testing (PT) as part of the diagnostic procedure., Objectives: To describe the epidemiological, clinical, and allergic profile of patients with a primary or secondary diagnosis of psoriasis undergoing PT and compare them with patients with a diagnosis of ACD at the end of the diagnostic process., Methods: Cross-sectional study with data from REIDAC from 2018 through 2023 of selected patients with a diagnosis of psoriasis and/or ACD., Results: A total of 11 502 patients were included, 513 of whom had been diagnosed with primary or secondary psoriasis, 3640 with ACD, and 108 with both diseases. Men were more predominant in the groups of patients with psoriasis, psoriasis+ACD, and lesions were more predominantly seen in the hands with little association with atopic factors vs the ACD group. The rate of positivity in PT to the 2022 Spanish battery of allergens was lower in the group with psoriasis only in 27% of the patients. The most common allergens found in the psoriasis group were also the most common ones found in the overall ACD population., Conclusions: Overall, 36.2% of psoriatic patients tested positive in PT to the 2022 Spanish battery of allergens, which proved that this association is not uncommon. Overall, psoriatic patients had a higher mean age, were more predominantly men, and showed more hand involvement., (Copyright © 2024 AEDV. Publicado por Elsevier España, S.L.U. All rights reserved.)

Background: Current frequency and features for positivity to textile dye mix (TDM) in Spain are unknown., Objectives: To study the frequency, clinical features and simultaneous positivity between TDM, para-phenylenediamine (PPD) and specific disperse dyes., Materials and Methods: We analysed all consecutive patients patch-tested with TDM from the Spanish Contact Dermatitis Registry (REIDAC), from 1 January 2019 to 31 December 2022. Within this group, we studied all selected patients patch-tested with a textile dye series., Results: Out of 6128 patients analysed, 3.3% were positive to the TDM and in 34% of them, the sensitization was considered currently relevant. TDM positivity was associated with working as a hairdresser/beautician and scalp, neck/trunk and arm/forearm dermatitis. From TDM-positive patients, 57% were positive to PPD. One hundred and sixty-four patients were patch-tested with the textile dye series. Disperse Orange 3 was the most frequent positive dye (16%). One of every six cases positive to any dye from the textile dye series would have been missed if patch-tested with the TDM alone., Conclusions: Positivity to TDM is common in Spain and often associated with PPD sensitization. TDM is a valuable marker of disperse dyes allergy that should be part of the Spanish and European standard series., (© 2024 The Authors. Contact Dermatitis published by John Wiley & Sons Ltd.)

Background: There is still limited clinical-practice data on specific clinical and patch test features, as well as on allergen clusters in polysensitization (PS)., Objectives: To determine the frequency, relevance, symptoms duration and risk factors in polysensitized patients and to assess possible allergen aggregation., Methods: Prospective multicentric study (January 2019-December 2022) conducted in setting of the Spanish Contact Dermatitis Register (REIDAC). Clinical and patch test data of polysensitized and oligosensitized patients were compared, and risk factors of PS were investigated with logistic multivariate regression. Unsupervised hierarchical clustering and network analysis were used to study allergen aggregation in PS., Results: A total of 10,176 patients were analysed. PS was found in 844 (8.3%). Current relevance was significantly higher in polysensitized patients (p < 0.01). Risk factors for PS were atopic dermatitis (OR: 1.58, 95% CI: 1.24-2.02), age (≥60 years vs. ≤24 years, OR: 1.75, 95% CI: 1.25-2.44) and some special locations (legs vs. face OR: 1.54, 95% CI: 1.05-2.25, hands vs. face OR: 1.46, 95% CI:1.15-1.85, arms vs. face OR: 1.49, 95% CI:1.01-2.20, trunk vs. face OR: 1.40, 95% CI:1.06-1.85). Cluster and network analyses revealed specific-allergen clusters and significant associations, including allergens belonging to metals group, fragrances and botanicals group, topical drugs group, rubber allergens and biocides., Conclusions: This study confirms that PS is structured by discernible patterns of specific-allergen clusters and reinforces significant allergen associations in PS. Cross-reactivity and/or concomitant sensitization could explain the formation of allergen clusters in PS., (© 2024 European Academy of Dermatology and Venereology.)

Background: Persistent localized dermatitis (PLD) or eczema flare-ups (EF) may occur in atopic dermatitis (AD) patients treated with dupilumab. They may reflect concomitant allergic contact dermatitis (ACD) exposed by the inhibition of the Th2 pathway by dupilumab in some cases. Objective: To evaluate the prevalence and etiology of these events and the impact of dupilumab on patch test outcome. Methods: We performed patch tests on 54 AD patients treated with dupilumab and evaluated the prevalence and final diagnosis of EF and PLD as well as the patch test results. Results: The patch test results were positive in 20/54 (37.0%). 21/54 patients (38.9%) had PLD and 12/54 (22.2%) had EF. Ten of 54 (18.5%) had both conditions and 11/54 (20.4%) had neither PLD nor EF. 64.5% of PLD involved the face. 83.9% patients with PLD and 90.9% patients with EF were diagnosed with inadequately controlled AD. 9.7% patients with PLD and 4.5% patients with EF were finally diagnosed with ACD. Nine of 21 (42.9%) patients patch tested twice were positive either before and/or during dupilumab. Patch tests results changed over time in all of them. Conclusions: Patch testing assisted us to exclude ACD as the cause of PLD/EF in AD patients treated with dupilumab. Most PLD and EF were, however, diagnosed as poorly controlled AD. Dupilumab appeared to impact the patch test outcomes.

Background: Current frequency and risk factors for sensitization to methylisothiazolinone (MI), methylchloroisothiazolinone/methylisothiazolinone (MCI/MI), benzisothiazolinone (BIT) and octylisothiazolinone (OIT) in Spain are not well known., Objectives: To study the frequency of sensitization, risk factors and simultaneous sensitization between the four isothiazolinones., Materials and Methods: We analysed all 2019-2021 consecutive patients patch-tested with MI (0.2% aq.), MCI/MI (0.02% aq.), BIT (0.1% pet.) and OIT (0.1% pet) within the Spanish Contact Dermatitis Registry (REIDAC)., Results: A total of 2511 patients were analysed. Frequencies of sensitization were: any isothiazolinone 15.7%, MI 6.8%, MCI/MI 4.8%, BIT 3.5% and OIT 0.5%. MI and MCI/MI sensitization was associated with being occupationally active, hand dermatitis, detergents and age over 40. BIT sensitization was associated with leg dermatitis and age over 40. About one in nine MI-positive patients were positive to BIT, whereas one in five BIT-positive patients were positive to MI., Conclusions: Sensitization to MI, MCI/MI and BIT is still common in Spain, while sensitization to OIT is rare. Currently, sensitization to MI and MCI/MI seems to be occupationally related. Although its origin is unknown, sensitization to BIT is more frequent in patients aged over 40 years. Simultaneous sensitization between MI and BIT is uncommon., (© 2022 The Authors. Contact Dermatitis published by John Wiley & Sons Ltd.)

Background: Allergic contact dermatitis from glucose sensors may interfere with their ongoing application., Objective: To evaluate a series of Spanish patients with contact dermatitis to glucose sensors regarding former sources of contact allergens, patch test results, and outcomes from the ongoing use of the device., Methods: A series of patients with contact dermatitis from glucose sensors was investigated in eight dermatology departments across Spain (epidemiological features, brands, latency time to develop dermatitis, the ability to continue using the devices as well as the patch test results)., Results: Thirty patients were evaluated (mean age 20.9 years). A total of 66.7% were children and 66.7% female. Ninety per cent used Freestyle Libre (FSL). Eight of 26 (30.8%) reacted to isobornyl acrylate (IBOA) and two of 20 (10.0%) to N,N dimethylacrylamide (DMAA). The mean latency time to develop dermatitis was 9 months. Sixteen of 29 (55.2%) patients continued using the same sensor causing the reaction. Thirteen of 29 (44.8%) patients were unable to continue using the sensor because of severe reactions. Of these, five were positive to IBOA, one to IBOA and DMAA, one to DMAA, one to colophony, and one to isopropyl alcohol wipes. In one patient, the outcome was unknown., Conclusion: The frequency of sensitisation to IBOA and DMAA, was lower than in other European series, but similar to a previously published Spanish article. Legislation requiring manufacturers to provide information regarding the composition of medical devices and cooperate with the investigations into contact dermatitis is urgently needed., (© 2021 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Vibratory urticaria/angioedema is an inducible type of urticaria that may be elicited by vibratory stimuli from work tool and instruments. A 39-year-old male construction worker was diagnosed with acquired vibratory angioedema associated with chronic spontaneous urticaria involving a severe work performance impairment. Response to omalizumab was immediate and complete. We evaluated the Urticarial Activity Score; the response to the vibratory angioedema provocation vortex test; and evolution of analytical parameters (e.g. high-affinity IgE receptor expression on peripheral blood basophils, C-reactive protein, D-dimer and IgE levels). Vibratory angioedema may be misdiagnosed as delayed pressure urticaria if the appropriate specific provocation tests are not performed. According to our knowledge, this is the first time a pneumatic hammer is described as a trigger; the first case responding to omalizumab; and the second published case associated with spontaneous chronic urticaria., (© The Author(s) 2022. Published by Oxford University Press on behalf of the Society of Occupational Medicine. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Background: We recently identified an outbreak of occupational allergic contact dermatitis (ACD) involving workers of a Spanish company selling smartphone protective cases from a glue product. A chemical analysis of one glue sample revealed the presence of 4-acryloylmorpholine among other allergens.The same glue is also used to attach tempered glass protective cases to Apple smartwatches., Objective: Our objective was to describe a case series of nonoccupational consumer ACD from the previously mentioned Apple smartwatch protective case glue., Methods: We evaluated epidemiological and clinical data, as well as patch tests results., Results: Three women were diagnosed with nonoccupational ACD from the adhesive. An annular vesicular inflammatory plaque involving the dorsal aspect of the wrist was initially observed in all. Two of the 3 patients were patch tested with 4-acryloylmorpholine 0.5% with positive strong reactions. Both also strongly reacted to a sample of the glue semiopen tested in a drop of petrolatum. One of them was also positive for various acrylates., Conclusions: 4-Acryloylmorpholine has been identified in an adhesive used to attach protective cases to smartwatches. Nonoccupational ACD have been described to involve consumers of smartwatches. A UV-curable adhesive used to attach protective cases to smartwatches has been considered to be the culprit., Competing Interests: The authors have no funding or conflicts of interests to declare., (Copyright © 2022 American Contact Dermatitis Society. All Rights Reserved.)

Background: Sensitization to acrylates is a concern in the occupational/environmental dermatology field., Objective: To describe an occupational allergic contact dermatitis (ACD) outbreak from a smartphone screen protector glue., Methods: Thirteen affected workers of a chain store selling phone screen protectors were investigated in five Spanish dermatology departments. The glue datasheet and label were assessed. A chemical analysis of the glue was performed. Based on this, some patients underwent additional testing., Results: All patients (all female, mean age: 25) had severe fingertip dermatitis. The datasheet/label indicated that the glue contained isobornyl acrylate (IBOA), a "photoinitiator" and polyurethane oligomer. The company informed us that the ingredients were polyurethane acrylate, "methacrylate" (unspecified), acrylic acid, hydroxyethyl methacrylate, propylmethoxy siloxane, and photoinitiator 184. Isobornyl acrylate (or IBOA) and N,N-dimethylacrylamide (DMAA) were patch tested in eight and two cases, respectively, with negative results. A chemical analysis revealed 4-acryloylmorpholine (ACMO); isobornyl methacrylate (IBMA), and lauryl acrylate in one glue sample. Seven patients were patch tested with dilutions of the identified substances and six of seven were positive for ACMO 0.5% pet., Conclusion: An outbreak of occupational ACD, likely from ACMO in a glue is described. Further investigations are needed to corroborate the role played by each compound identified in the chemical analyses., (© 2022 The Authors. Contact Dermatitis published by John Wiley & Sons Ltd.)

Background: Hand eczema is common in patients with atopic dermatitis (AD), but few studies have described the characteristics of these patients in large, representative populations from different geographic regions and occupational settings., Objective: To describe the epidemiological, clinical, and allergy profile of patients with hand eczema who underwent patch testing and compare patients with and without AD., Methods: Analysis of data from the Spanish Contact Dermatitis Registry, a multicenter registry of patients who undergo patch testing in Spain., Results: We included 1466 patients with hand eczema who were patch tested between January 2018 and June 2020. Those with AD were younger and had had symptoms for longer before testing. They were also more likely to have been exposed to occupational triggers (38% vs 53% for patients without AD). The only profession for which significant differences were found was hairdressing. The most common allergens were nickel sulfate, methylchloroisothiazolinone/methylisothiazolinone, cobalt chloride, potassium dichromate, fragrance mixes I and II, and formaldehyde. The most common diagnoses were allergic contact dermatitis (24% vs 31% in patients with and without AD, P=.0224) and irritant contact dermatitis (18% and 35% respectively, P<.001)., Conclusions: AD is common in patients with predominant hand eczema who undergo patch testing. Patients with hand eczema and AD have different clinical and epidemiological characteristics to hand eczema patients in general and their final diagnosis following patch testing is also different., (Copyright © 2021 AEDV. Publicado por Elsevier España, S.L.U. All rights reserved.)

Background: Methyldibromo glutaronitrile (MDBGN) was one of the most frequent and relevant allergens found in patch testing at the beginning of this century. In 2008, this preservative was banned from cosmetics in Europe and ever since the prevalence of contact allergy to MDBGN has progressively decreased. Despite that gradual decline, MDBGN is still patch-tested in most baseline series. This study assessed the frequency of MDBGN sensitization, epidemiological characteristics of allergic patients, and the relevance of positive patch tests in a nationwide Spanish registry (REIDAC)., Patients and Methods: We evaluated consecutively patch-tested patients in all participating centres. Using these data, we calculated the proportion of patients with positive patch tests to MDBGN from June 2018 to June 2020 and evaluated the relevance of the positive patch tests., Results: One hundred and fourteen out of 5072 (2.24 %) tested patients were sensitized to MDBGN. Clinical current relevance was confirmed in only one case., Conclusion: Although the frequency of contact allergy to MDBGN remains high, no clinical significance was found in most of these patients (5072 tests needed to obtain one relevant positive result). The clinical usefulness of this allergen seems weak and its continued inclusion in the European baseline series is questionable., (© 2021 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)