Polysensitization in the Spanish Contact Dermatitis Registry (REIDAC): A 2019-2022 prospective study with cluster and network analysis.

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.

Sensitization to textile dyes in Spain: Epidemiological situation (2019-2022).

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.

2-Hydroxyethyl methacrylate (2-HEMA) sensitization, a global epidemic at its peak in Spain?

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.

Sensitization to isothiazolinones in the Spanish Contact Dermatitis Registry (REIDAC): 2019-2021 epidemiological situation.

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.

Outbreak of occupational allergic contact dermatitis from a smartphone screen protector glue.

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.

Should methyldibromo glutaronitrile continue to be used in the European baseline Series? A REIDAC national cross-sectional study.

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.

Contact allergy to isothiazolinones epidemic: Current situation.

BACKGROUND: Since 2009, an increasing number of published cases of allergic contact dermatitis (ACD) from isothiazolinones in Europe was observed, amounting to an epidemic. However, only few studies have assessed the current situation after changes in European regulation. OBJECTIVES: To analyze the incidence of isothiazolinone-related ACD in our area in the last decade. METHODS: A retrospective study analyzed all patients patch tested in the allergy unit in a tertiary hospital in Spain between January 2010 and June 2019. Positive patch-test reactions to methylchloroisothiazolinone (MCI)/methylisothiazolinone (MI) and/or MI alone were recorded. RESULTS: A total of 243 patients (9.55%) with positive patch-test reactions to MCI/MI and/or MI alone among 2544 consecutively patch-tested patients were recorded. An initial increase in the prevalence of MCI/MI allergy was observed, from 4.5% in 2010 reaching a peak in 2015, which was followed by a significant decrease until July 2019 with 3.1% prevalence in 2019. CONCLUSIONS: As shown in our data, regulatory interventions have resulted in a dramatic decrease in the prevalence of MCI and MI ACD, reaching a pre-epidemic level of 3.1% in 2019.

Allergic and photoallergic contact dermatitis to chlorpromazine.

Chlorpromazine is known to produce both systemic phototoxic and photoallergic reactions. However, it may also cause photoallergic contact dermatitis and, albeit exceptionally, allergic contact dermatitis (ACD). We present a series of photoallergic contact dermatitis and ACD to chlorpromazine diagnosed at a tertiary centre cutaneous allergy unit between 1980 and 2019.

European photopatch test baseline series: A 3-year experience.

BACKGROUND: In 2012, a consensus was reached regarding a baseline photopatch test series on the basis of the results of a European multicentre study. OBJECTIVES: To describe experience with the European photopatch test series. METHODS: A retrospective analysis of 116 patients tested with the European photopatch test series between 2014 and 2016 was performed. RESULTS: Fifty-five positive photopatch test reactions in 25 subjects were recorded, most commonly caused by the topical non-steroidal anti-inflammatory drugs ketoprofen, dexketoprofen, and etofenomate. Organic ultraviolet (UV) absorbers constituted the second main category of agents eliciting positive photopatch test reactions. Among UV absorbers, benozophenone-3 and octocrylene were the most frequent photoallergens. UV absorbers that have been introduced more recently rarely elicited positive photopatch test reactions. Positive patch test reactions were less commonly observed than positive photopatch test reactions, namely, 21 reactions in 14 patients. CONCLUSIONS: We present the largest clinical experience with the European photopatch test baseline series hitherto reported. The results are similar to those underlying the above consensus process, reaffirming the usefulness of this series.

Allergic contact dermatitis to chlorhexidine in pediatric patients.

Chlorhexidine is one of the most widely used antiseptics in our environment. Allergic contact dermatitis to chlorhexidine is common in adults, but is quite rare in the pediatric population. Its diagnosis is important because it can mimic other dermatoses common during childhood, and it can also lead to acute immediate hypersensitivity reactions following successive exposures.

Dermatitis of the Foot: Epidemiologic and Clinical Features in 389 Children.

BACKGROUND/OBJECTIVES: Footwear dermatitis is a form of contact dermatitis resulting from exposure to shoes. There have been only small studies regarding foot contact dermatitis in children. The present study was undertaken to define the prevalence and epidemiologic and clinical features of shoe dermatitis in children. METHODS: A retrospective study was undertaken of all children referred for patch testing between 1996 and 2015. Children with dermatitis limited to the feet were selected. RESULTS: We collected data from 389 children younger than 16 years, 52 of whom (13.4%) were referred with dermatitis exclusively on the feet. Diagnosis after patch testing was allergic contact dermatitis in 23 children (44.2%), atopic eczema in 12 (23.1%), juvenile plantar dermatosis in 8 (15.4%), dyshidrotic eczema in 6 (11.5%), irritant contact dermatitis in 2 (3.8%), and tinea pedis in 1 (1.9%). The most frequent allergens were potassium dichromate, thimerosal, cobalt chloride, mercapto mix, colophonium, mercury, and nickel(II) sulfate. CONCLUSION: Allergic contact dermatitis caused by footwear is a common cause of foot dermatitis in children. Children with foot dermatitis should be referred for patch testing when an allergic origin is suspected.