Translation of a-t 2019; 50: 30
CURRENT ADR NETWORK REPORT
Allergic reactions to FREESTYLE LIBRE disposable sensors
A 50-year-old man with diabetes mellitus uses the sensor-based glucose measuring system FREESTYLE LIBRE to control his glucose levels (see a-t 2015; 46: 47). The patient has been complaining of an allergic reaction with reddening and itching in the region of the adhesive point for several months which only improved after the last disposable sensor was removed (NETZWERK report 17.642). The FREESTYLE LIBRE sensor is adhered to the upper arm and uses a pin point pushed under the skin to continuously measure the glucose level in the interstitial fluid of the subcutaneous fat tissue and sends the data to a reader when this is placed over the sensor. After two weeks a new sensor needs to be applied and the old one disposed of as "electronic waste" (1). At the end of last year, the Drug Commission of the German Medical Association (AkdÄ) warned about contact allergies to the sensor following five reports (2). The German Federal Institute for Drugs and Medical Devices (BfArM) has now documented 101 allergic events (3). It is evidently not the ingredients used for the adhesive film that are responsible for the skin reactions. In patch testing those affected react to the isobornyl acrylate (IBOA) found in the sensor material. This is part of an adhesive that binds the plastic parts of the sensor together and spreads from there (2, 4-6). The search for the trigger was made more difficult since materials used in medical devices do not have to be declared (5) and because the supplier Abbott - according to the AkdÄ - was only very reluctantly involved in the attempt to explain the skin reactions (2). At least Abbott will stop using this allergenic ingredient in the production of the sensor "from the first quarter of 2019" (3). However, another substance found in the sensor, dimethylacrylamide (DMAA), triggered a skin reaction in the patients tested in a patch test, too (6).
| 1 | Abbott: Letter dated 13 Feb. 2019 |
| 2 | AkdÄ: Dtsch. Ärztebl. 2018; 115: A2260-1 |
| 3 | BfArM: Letter dated 1 March 2019 |
| 4 | HERMAN, A. et al.: Contact Dermatitis 2017; 77: 367-73 |
| 5 | KAMANN, S. et al.: J. Diabetes Sci. Technol. 2018; 12: 630-3 |
| 6 | MOWITZ, M et al.: Contact Dermatitis 2019; published online on 18 Feb. 2019; doi: 10.1111/cod.13243 |
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