The Dexcom glucose monitoring system-An isobornyl acrylate-free alternative for diabetic patients

Contact Dermatitis. 2019 Jul;81(1):32-36. doi: 10.1111/cod.13248. Epub 2019 Mar 29.


Background: Glucose monitoring systems, for example, Freestyle Libre (Abott) and Dexcom (Nintamed), are increasingly being used instead of conventional blood sugar measurement. However, many patients have experienced adverse skin reactions such as severe allergic contact dermatitis (ACD). Finally, in August 2017, the culprit allergen in Freestyle Libre, isobornyl acrylate (IBOA), was identified.

Objectives: After patients have developed ACD, it is recommended that they no longer use their glucose monitoring systems. Thus, it is important to find an alternative IBOA-free device.

Patients and methods: Five patients presented with ACD caused by Freestyle Libre. Each was patch tested with allergens from the baseline series and from a plastics and glues series, and additionally with IBOA 0.1% pet. Gas chromatography-mass spectrometry (GC/MS) of the Freestyle Libre sensor and the Dexcom sensor was performed. The Dexcom sensor remained on the skin of all patients for at least 2 days.

Results: All patients were sensitized to IBOA. GC/MS showed the presence of IBOA in the Freestyle Libre sensor, whereas the Dexcom sensor was IBOA-free. None of the patients had skin reactions to the Dexcom sensor.

Conclusions: Patients with Freestyle Libre and IBOA allergy may use the Dexcom sensor as an alternative for glucose monitoring.

Keywords: Dexcom; Freestyle Libre; acrylates; allergic contact dermatitis; continuous glucose monitoring systems; flash glucose monitoring system; insulin pump; isobornyl acrylate; patch test.

MeSH terms

  • Acrylates / adverse effects*
  • Adhesives / chemistry
  • Adult
  • Blood Glucose Self-Monitoring / instrumentation*
  • Camphanes / adverse effects*
  • Child
  • Dermatitis, Allergic Contact / etiology*
  • Dermatitis, Allergic Contact / prevention & control
  • Diabetes Mellitus / therapy*
  • Female
  • Humans
  • Male
  • Middle Aged


  • Acrylates
  • Adhesives
  • Camphanes
  • isobornyl acrylate