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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: 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.)