Institutional repository IRUAThis article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process which may lead to differences between this version and the Version of Record. Please cite this article as doi: 10.1111/cod.13626 Surgical mask dermatitis caused by formaldehyde (releasers)during the COVID-19 pandemic.

Background Concomitant positive patch test reactions in patients sensitized to isobornyl acrylate (IBOA) have rarely been documented. Objectives To report concomitant sensitizations in patients with allergic contact dermatitis (ACD) from the glucose sensor FreeStyle Libre and sensitized to IBOA. Methods In 2019, 26 patients with suspected ACD from FreeStyle Libre were patch tested to a baseline series and to a (meth) acrylate series containing IBOA and 2‐phenoxyethyl acrylate (PEA) 0.1% pet. Diabetes devices and patch test preparations were analyzed with gas chromatography – mass spectrometry (GC‐MS) for the presence of IBOA and PEA. Results Of the 26 patients, 18 (69%) were sensitized to IBOA, and eight (44%) and 11 (61%) of these were co‐sensitized to sesquiterpene lactones and fragrances, respectively. Ten patients (56%) were co‐sensitized to PEA, which, contrary to IBOA, could not be detected in any device. The PEA test material was shown to be contaminated with IBOA. Conclusions Contact allergy to IBOA appears to be declining and IBOA‐sensitized patients are most often co‐sensitized to sesquiterpene lactones and fragrances. Vigilance is required when patch testing (acrylate) materials obtained from industry, as these might be contaminated and, hence, alter the results and their interpretation.

Cutaneous adverse events (CAE) from FreeStyle Libre include allergic contact dermatitis (ACD) caused by the allergen isobornyl acrylate (IBOA). We aim to report CAE from this glucose sensor, ACD to IBOA in particular, and the outcome of using barrier films as a prevention. RESEARCH DESIGN AND METHODSA monocentric, retrospective review of medical files from adult and pediatric patients with diabetes using Freestyle Libre, in the period between December 2016 and April 2019, was performed with a focus on CAE. RESULTSFifty-seven of 1,036 patients with diabetes (5.5%) were referred to our dermatology department because of CAE from FreeStyle Libre. Thirty-nine of 1,036 (3.8%) had ACD due to IBOA. Only two patients, of whom one sensitized to IBOA, had a benefit from using barrier films. CONCLUSIONSCAE occurred in 5.5% of FreeStyle Libre users, and 3.8% suffered from ACD due to IBOA. Barrier films had limited value in the prevention.FreeStyle Libre (Abbott Diabetes Care, Witney, U.K.) is a sensor-based, flash-continuous glucose monitoring system applied on the skin for up to 14 days (1). However, it contains isobornyl acrylate (IBOA), a newly discovered allergen, which may cause allergic contact dermatitis (ACD) (2-5). We report a single-center experience of cutaneous adverse events (CAE) from this glucose sensor, including ACD due to IBOA, and the outcome of using barrier films as a prevention in these patients. RESEARCH DESIGN AND METHODSThe medical files of 614 adult and 422 pediatric patients with diabetes, using FreeStyle Libre in the period between December 2016 and April 2019, were retrospectively reviewed with a focus on CAE. In our center, patients are usually referred to the dermatology department for an allergy workup, including patch tests with IBOA 0.1% dispersed in petrolatum according to published guidelines (6). Whenever a barrier film (Cavilon No Sting Barrier Film) had been used to prevent the CAE ( 7), applied according to the manufacturers' recommendations, its impact on the CAE was verified.