Patch testing and diagnosis when suspecting allergic contact dermatitis from medical devices

Continuous glucose monitoring systems give contact dermatitis in children and adults despite efforts of providing less ‘allergy‐ prone’ devices: investigation and advice hampered by insufficient material for optimized patch test investigations

“…With access to sufficient device material, the possibility to improve the extracts used increases and thus the chance of actually finding a culprit allergen through patch testing. When the patch testing of an extract gives a positive reaction followed by negative reactions in controls, the extract can be used for separation and identification based on patch testing with thin layer chromatograms 33 . The need to patch test accurately is clearly indicated as the allergens in the medical devices, however, relevant, may be found in low concentrations.…”

“…When contacted, the parents of one of the patients (no:1) stated that their daughter had been able to use of Dexcom G6 ® and that the skin problems were fluctuating, indicating a possible irritant reaction. When a patient with a suspected ACD reaction to medical devices is investigated, there is a need to consider several possible pitfalls in the diagnostic setup 33 . Whether all the correct allergens have really been patch tested and in the right dose.…”

Changes in adhesive ingredients in continuous glucose monitoring systems may induce new contact allergy pattern

“…For many sensitizers, including preservatives, the required patch test concentration is around 20 times higher than in leave-on products,which at patch testing may give false negative reactions. 1 Whether an optimal patch test concentration for 2,2 0methylenebis(6-tert-butyl-4-methylphenol) monoacrylate would be around 1.5% needs to be carefully investigated in order to avoid active sensitization. 24 A third possible explanation is that a low grade inflammatory reaction to IBOA, and in 2 cases colophony and colophony-related substances, caused enhanced penetration of allergens, thus inducing a greater total reaction.…”

“…Investigating patients with suspected allergic contact dermatitis to medical devices (MDs), such as continuous glucose monitoring (CGM) systems, intermittently scanned glucose monitoring (isCGM)/flash glucose monitoring systems, and insulin pumps, is complicated. 1 The diagnosis has to be suspected and the patient must be patch tested with the right substances. The investigation should also include patch testing with the patient's own material.…”

“…2 Producing an extract can in itself be difficult because of the lack of material, especially if extraction solvents with different physico-chemical properties are desired. 1 The culprit contact allergens found have mainly been used in attachment areas, ie, where different materials must adhere to each other, but not necessarily primarily in the adhesive patch in direct contact with the skin. Therefore, identifying and finding the optimal patch test substance and dose has been complex, as the final dose on skin exposure is not necessarily the same as where the substance is identified used.…”