Allergic contact dermatitis caused by glucose sensors in type 1 diabetes patients

Background Allergic contact dermatitis caused by glucose sensors has become an increasing problem. Contact allergies to isobornyl acrylate, colophonium, ethyl cyanoacrylate and N,N-dimethylacrylamide have been reported. However, there is a paucity of information regarding the prevalence of sensor-related dermatitis and detailed patient histories. Objectives To evaluate diabetes patients who have developed allergic contact dermatitis caused by glucose sensors. Patients and methods Seventy patients with suspected contact allergy to glucose sensors referred to university hospital dermatology clinics in southern Finland were patch tested with the baseline series, an isobornyl acrylate dilution series, and a number of other acrylates. Atopic constitution, contact allergies, the severity of the dermatitis and the ability to continue with the same or another type of sensor were recorded. Results Positive patch test reactions to isobornyl acrylate were seen in 51 of 63 (81%) Freestyle Libre users. Colophonium or its derivatives gave positive reactions in five of seven Medtronic Enlite users. The median duration of sensor use before dermatitis was 6 months. The estimated prevalences of contact allergy to sensor adhesives were 0.7% for Freestyle Libre and 0.8% for Enlite. Conclusions We suggest that patients who have difficulties in finding a tolerable glucose sensor or an insulin pump should be patch tested.