Pedro Mercader‐García

Chronic spontaneous urticaria (CSU) remains difficult to manage in patients refractory to antihistamines and omalizumab. Although dupilumab has recently been approved and incorporated into international guidelines, real-world evidence remains limited, particularly in treatment-refractory populations. We conducted a multicentre ambispective cohort study across 16 Spanish hospitals including adults with CSU, with or without concomitant chronic inducible urticaria, treated with dupilumab and followed for ≥4 weeks. The primary outcome was well-controlled disease within 24 weeks (Urticaria Control Test ≥12 and Urticaria Activity Score over 7 days≤6). Fiftyone patients were included; 92.0% had previously received omalizumab. At week 24, 69.7% (23/33) achieved well-controlled disease and 39.4% (13/33) complete control. Among patients with available week-52 data, 90.5% (19/21) and 61.9% (13/21), respectively, achieved these outcomes. Concomitant therapy use declined from 94.1% at baseline to 55.6% at week 52. Among omalizumab-experienced patients evaluable at week 24, dupilumab response was lower in prior nonresponders than in those with at least partial response to omalizumab (40% vs 85%, p=0.011). Atopic comorbidities were associated with greater UAS7 reduction (p=0.018). Dupilumab was well tolerated, with mostly mild adverse events. In routine clinical practice, dupilumab provides effective disease control in patients with difficult-totreat CSU, including most omalizumab-experienced individuals.

Background: Dyshidrotic eczema (DE), also termed acute and recurrent vesicular dermatitis, is a vesicular clinical pattern of hand eczema (HE) with heterogeneous aetiologies. Objectives: To characterise the clinical‐allergological profile of patients with DE and to compare it with non‐DE HE subtypes. Methods: A multicentre, retrospective, observational study was conducted using data from the Spanish Contact Dermatitis Registry (2019–2024). Results: Of 4378 patients with HE, 559 were diagnosed with DE. A longer median disease duration (24 vs. 14 months) and more frequent palmoplantar involvement (16% vs. 7%) were observed in DE compared with non‐DE HE. At least one positive patch test was identified in 43% of DE versus 52% in non‐DE HE. Although overall sensitisation patterns were largely comparable, DE showed lower sensitisation rates to 2‐HEMA, carba mix and thiuram mix. Occupational factors were less frequently implicated in DE (9% vs. 29%) compared with non‐DE HE. Conclusions: Despite a high overall frequency of contact allergen sensitisation, the pattern of findings suggests that the dyshidrotic phenotype may follow a clinical course less dependent on external or occupational triggers, pointing towards a relatively greater contribution of endogenous factors compared with other HE subtypes.

Anti-TNFα agents have been associated with the reactivation of granulomatous infections, including leishmaniasis. Cases of atypical or recurrent cutaneous (CL) or mucocutaneous leishmaniasis (MCL) have been reported in patients on biologics. We conducted a retrospective analysis of a multicenter database to describe the clinical characteristics and management of CL and MCL in patients receiving biological therapy in an endemic area. Clinical features, diagnostics, therapies, and outcomes were analyzed. Seventy-one patients were included (63 CL and 8 MCL). The most common underlying condition was inflammatory bowel disease (33.8%). Lesions were multifocal in 40% and larger than 1 cm in 94.4%. Treatment failures were more frequent in MCL (50%) than CL (8.1%). Biologic therapy was discontinued in 53.5%, leading to worsening of the underlying disease in 44.7%. No significant difference in cure rates was observed between patients who continued vs. discontinued biologics (p=0.868). These findings highlight the clinical burden of CL and MCL in patients undergoing anti-TNFα therapy and suggest that discontinuation of biologic therapy did not significantly impact cure rates, emphasizing the need for standardized strategies balancing infection control and underlying inflammatory disease management.

Background: Current relevance of positive patch‐test reactions guides management in allergic contact dermatitis (ACD), yet its clinical predictors and the use of predictive models in clinical practice remain underused. Objectives: To identify demographic and clinical factors associated with current relevance in ACD and to develop overall and allergen‐specific predictive models. Methods: A multicentric REIDAC study included data from patch‐tested patients with the Spanish baseline series. Exposure history, anatomical sites, atopic status, and occupational data were recorded. Logistic regression (LR) models were trained and internally validated to predict current relevance overall and for top frequent allergens. Model discrimination was assessed with area under the receiver‐operating characteristic curve (AUC). Results: Among 17 005 patients, 4077 (24.0%) had at least one currently relevant reaction. The final overall LR model achieved an AUC for the validation sample of 0.679. Allergen‐specific AUC parameters (LR) varied among allergens but performed best for nickel (AUC = 0.770). The independent factors associated with current relevance were female gender, specific body sites (hand, neck, head, leg, feet) and two occupations (hairdresser and construction workers). The use of other models (LASSO, gradient boosting) revealed similar results. Conclusions: Prediction modelling may moderately predict current relevance in ACD and several clinical variables are associated with current relevance in ACD.

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.

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.

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.

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.

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.

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.