CD19 Contact allergy to colophonium and Abitol in a continuous glucose monitor securing tape

Abstract We present the case of a young boy using a continuous glucose monitor (CGM) to manage his insulin-dependent diabetes. Some months after first use, he developed a blistering dermatitis at the sites of contact. Further inspection revealed the location was beneath the tape used to secure his CGM. The reaction started 1–2 days after he moved the device each time, resolving a few days after removal. Matters cleared on changing to an alternative tape. He had not used any tackifiers or hydrocolloid dressings. He was patch tested to an acrylate series including ethyl cyanoacrylate (ECA); hexanediol diacrylate (HDDA); iso­bornyl acrylate (IBOA) 0.1% in petrolatum; a plasticizer and glue series including Abitol, abietic acid and colophonium; sesquiterpene lactone and compositae mixes; the device; ancillary products comprising the original securing tape, the new tape, adhesive remover and barrier wipe; and topical preparations used (the standard series was omitted due to lack of space). Our patient reacted on days 2 and 4 as follows: the tape concerned (++/++), Abitol (++/+++) and colophonium (++/++). Allergic and irritant contact dermatitis to glucose monitors and insulin pumps and to ancillary products is increasingly reported. Supplied information on the composition of devices is limited, with most allergenic constituents being identified by external chemical analysis. These include colophonium and derivatives, for example Abitol – at up to 15% – ECA, HDDA and IBOA, which are available in commercial patch test formulations. Others are not available, including dicyclohexylmethane-4,4′-diisocyanate, 2,2′-methylenebis(6-tert-butyl-4-methylphenol) mono­acrylate, N,N-dimethylacrylamide and dipropylene glycol diacrylate. Composition information appears to be more readily available for ancillary products, as in our case. Patient instructions for the tape, available online, list 5–10% colophonium (rosin) in the adhesive. We cannot exclude additional nonidentified allergens in the tape. The ingredients listed on the adhesive remover and on the packaging of the wipes were hexamethyldisiloxane and siloxanes, respectively. Absence of colophonium, Abitol and their derivatives in these two products was confirmed by the various manufacturers and absence of the device from published chemical analysis. We report a case of contact dermatitis secondary to colophonium in the adhesive of a securing tape for a CGM. Changing to an alternative tape ensured he did not need to change his device.