In Response to the Letter to the Editor on Minimizing Adverse Skin Reactions to Wearable Continuous Glucose Monitoring Sensors

Abstract

In the letter1 advantages of wearable continuous glucose monitoring (CGM) systems and insulin pumps for people with diabetes are emphasized. Worldwide, an increasing number of patients, particularly children, benefit from the use of these devices with improved quality of life. A widespread and lifelong use is an incitement for continuous development of the medical devices (MD). Today, skin reactions constitute a major cause of treatment discontinuation and many diabetes patients with an underlying contact allergy (CA) to the MD are reported.2 CA can only be diagnosed by patch testing. Commercially available patch test series contain few if any of the allergens found in MD, making diagnosis easily missed or significantly delayed, thus preventing individual guidance and information on exposures.3 To meet functional demands from users continuous improvement of the products is called upon. However, alterations in device content risk introducing new potential allergens, which in turn can cause even more contact allergies among users.4 Isobornyl acrylate (IBOA) was the first main sensitizer in CGM systems, but by no means the last one. The allergen was identified and cases of CA confirmed in university clinics without aid from the industry.5 Today, IBOA is just one of several allergens found in MD.2,4,5,6 Unfortunately, it has been found in various MD from different manufacturers. Even in MD claimed to be IBOA-free, the allergen has been identified albeit with much reduced content.6 Even low amounts of IBOA might cause dermatitis in a person with a strong CA.6 The trajectory from the first patients with skin problems and the allergen being identified to having products, free from or with reduced levels of allergen, on the market has by no means been straight.5 Confirming CA to MD, is significantly hampered by the lack of information on device content. It often demands personal sacrifices for the patient with regard to time to diagnosis, significant resources from the investigating clinics, and material for analysis. This resource-intense diagnostic workup threatens equal care for other patient groups having CA. The user with CA, often a child, is at lifelong risk of exposure to the allergen or crossreacting substance in MD and elsewhere. Today, a patient within the European Union with a cosmetic allergy can easily access information on the content of a cosmetic product. In contrast, a patient using a MD for 3-14days on occluded skin is not ensured any information on content. We see 2 main future problems. Primary sensitization: there will be new possible allergens in MD posing problems to the user and to the diagnosing dermatologist, and secondary prevention: CA is a lifelong condition. The best solution for the user would be full declaration of content. At least, whenever problems occur, a willingness from the producer to help and collaborate with the investigating dermatologist in diagnosing the patient rather than refusing communication5 is needed. The investigations to identify the culprit allergens are today performed in few places in the world, making the care unequal as well as posing a financial burden on these health care facilities.