In relation to the article by Velasco-Amadora et al.,1 on medical devices in patients with diabetes and contact dermatitis, and the information it contains regarding the FreeStyle Libre and FreeStyle Libre 2 sensors, the following considerations should be made to better guide professionals and patients: (i) since July 31, 2020, isobornyl acrylate (IBOA) has not been present in any shipment of FreeStyle Libre, FreeStyle Libre Pro, or FreeStyle Libre H devices; (ii) IBOA has never been present in FreeStyle Libre 2 or FreeStyle Libre 3 sensors2,3; (iii) independent researchers have observed that patients sensitized to IBOA tolerated the FreeStyle Libre 2 sensor3; (iv) 2,2′-methylenebis(6-tert-butyl-4-methylphenol) monoacrylate (MBPA) has never been present in FreeStyle Libre sensors.

Although IBOA and MBPA are identified as the allergens most frequently involved in skin sensitization among users of interstitial fluid glucose sensors,4,5 there is no guarantee that FreeStyle Libre sensors without IBOA or MBPA can prevent skin reactions, since there are other causes that may trigger them. Therefore, we recommend that, in the event of any skin reaction, the sensor be removed and the healthcare professional decide on case management.