Glucose monitors: Not as sweet as they seem

By Christen M. Mowad, MD
Oct. 9, 2019
Vol. 1, No. 31

The next contact allergen of the year has been announced early by the American Contact Dermatitis Society and it is an acrylate, isobornyl acrylate. (1) This chemical is a photopolymerizable monomer that has been used in industrial products such as UV-cured ink or adhesives. As a group, acrylates are well-known allergens. They are important allergens in patients exposed to them in various settings including: artificial nails, adhesives, dental composite fillings, dentures, hearing aids, personal hygiene pads, printing inks, rubber coatings, and UV cured glues, to name a few. Isobornyl acrylate has been identified as the allergen of the year to bring attention to its role as an allergen in a newer arena — glucose monitoring systems and insulin pumps.  

Isobornyl acrylate was first reported as an allergen in 1995 when 2 women developed eruptions around their insulin pump. (2) Another report of contact allergy to isobornyl acrylate was reported in 2013 in an occupational contact dermatitis setting; a patient working as a process operator involving glass fibers with an acrylate coating developed hand eczema. (3) More recently, several reports have been published describing allergic contact dermatitis to glucose monitoring systems and insulin pumps; the allergen has been identified as isobornyl acrylate. (4-9) 

Several new devices, including insulin pumps and glucose monitoring systems, have recently been developed to better manage patients with type I diabetes. Continuous or flash glucose monitoring systems have been introduced to provide easier, less onerous and painful monitoring of glucose compared to finger skin pricks. Additionally, insulin pumps can allow continuous subcutaneous insulin administration and some systems can both monitor glucose levels and provide insulin. These devices are applied to the skin with an adhesive and left in place for several days, some as long as two weeks. Examples of these devices include the Freestyle Libre and the Omnipod insulin management system. These systems have improved control of diabetes and quality of life in diabetic patients; however, several patients developed an allergic contact dermatitis at the site of their application. Identifying the source of the allergen has been challenging as the ingredients of these systems are not well delineated. Some researchers have been able to perform gas chromatography mass spectrometry to identify the allergen, which can be found at the juncture of the top and bottom of the device, or in the adhesive. (7,9) This type of testing is not widely available. The allergen isobornyl acrylate is not widely tested for and therefore may easily be missed.

Using the FDA-approved standard allergen testing series, this allergen would not be identified. Cross-reactivity among acrylates is not historically reliable. Although some acrylate screening series or mixes have been proposed, most patch testing clinics screen to a series of acrylate allergens which historically do not contain isobornyl acrylate. (3) As a result, the use of an expanded series including other acrylates may also miss this allergen. If a patient presents with a glucose monitoring system or insulin pumps, or the provider has a concern for this allergen, the provider should consider isobornyl acrylate as the causative allergen. Patch testing with the allergen should be performed in order to identify the allergen and perhaps acrylate screening trays should include this new allergen. (4) Patch testing is ideally performed with isobornyl acrylate 0.1% concentration. (3-6,8,9)
 
In order to prevent contact with the allergen some authors have designed a system where dressings are placed under the device in an attempt to decrease contact with the allergen, thereby muting the allergic contact dermatitis, allowing for continued use of the system. (6) Unfortunately, this is not always possible or convenient, so other systems may be necessary. (5,6) With the increase in allergic contact dermatitis to isobornyl acrylate being seen with these devices, providers need to be aware of the allergen in order to identify it. Additionally, some changes to manufacturing may be needed to allow diabetics to continue to benefit from these newer technologies that improve their glucose control and quality of life.

Point to remember: Dermatologists must be aware of a possible allergic contact dermatitis to isobornyl acrylate found in new glucose monitoring systems for diabetic patients. 

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Our editor’s viewpoint
Warren R. Heymann, MD

I recently published an article entitled “Glucose Monitoring Dermopathy” where a 75-year-old man had been monitoring his glucose using a blood glucose monitoring system at the same body site for at least 20 years (>7300 needlesticks). The site was a brown plaque that proved to be a dermal reparative reaction. (Skinmed 2018;16: 74-75). Certainly, avoidance of skin pricks by novel monitoring approaches have improved the quality of life for diabetic patients, unless an allergic contact dermatitis complicates their use.

The situation is best stated in the conclusion of Herman et al (reference 8): “The market introduction of the insulin pump, along with the FGM and CGM systems, has significantly improved diabetic patient self‐management and reduced potential complications such as hypoglycaemia and ketoacidosis. Owing to ACD caused by acrylates contained in these devices, and to the difficulties in identifying the culprit allergens, a number of patients need to, once again, measure blood glucose levels by finger pricking.

From a public health point of view, the control of the contact allergy epidemic and, specifically, the reduction of its impact are a challenge. Manufacturers should be motivated to search for less sensitizing materials, in addition to being obliged to disclose the complete chemical composition of all medical device parts.”

 1. Splete Heidi. Dermatologists name isobornyl acrylate contact allergen of the year. Dermatology News March 5, 2019.
2. Busschots AM, Meuleman C, Poesen N, Dooms-Goossens A. Contact allergy to components of glue in insulin pump infusion sets. Contact Dermatitis 1995:33:205-206.
3. Christoffers WA, Coenraads P, Schuttelaar MA. Two decades of occupational (meth)acrylate patch test results and focus on isobornyl acrylate. Contact Dermatitis 69: 86-92, 2013.
4. Herman A, Aerts, O, Baeck M et al. Allergic contact dermatitis caused by isobornyl acrylate in Freestyle Libre, a newly introduced glucose sensor, Contact Dermatitis 77, 367-373, 2017.
5. Oppel E, Kamann S, Reichl F, Hogg C. The Dexcom glucose monitoring system- an isobornyl acrylate-free alternative for diabetic patients, Contact Dermatitis 81(1):32-36, 2019.
6. Kamann S, Oppel E. Hydocolloid blister plaster decreases allergic contact dermatitis to Freestyle libre and isobornyl acrylate. Contact Dermatitis 30, 2019.
7. Raison-Peyron N, Mowitz M, Bonardel N, Aerts O, Bruze M. Allergic contact dermatitis caused by isobornyl acrylate in OmniPod, an innovative tubeless insulin pump. Contact Dermatitis 79:76-80, 2018.
8. Corazza M, Scuderi V, Musmeci D, Foti C et al. Allergic contact dermatitis caused by isobornyl acrylate in a young diabetic patient using a continuous glucose monitoring system (Freestyle Libre). Contact Dermatitis 79:320-321, 2018.
9. Herman A, de Montjoye L, Tromme I, Goossens A, Baeck M. Allergic contact dermatitis caused by medical devices for diabetes patients: A review. Contact Dermatitis 79: 331-335, 2018. 

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