Tetrahydrofurfuryl Methacrylate and Isobornyl Acrylate: Possible New Sensitisers in Hearing Aid Ear Moulds.

BACKGROUND

Allergic contact dermatitis from hearing aid ear moulds is infrequently reported.

OBJECTIVES

To identify cases of allergic contact dermatitis from hearing aid moulds in a cohort of patients investigated between 2022 and 2025 at Amsterdam University Medical Center.

MATERIALS AND

METHODS

Retrospective analysis of patients referred for investigation of suspected allergic reactions to ear moulds.

RESULTS

Of 20 patients with suspected allergic reactions to ear moulds, 8 (40%) had positive patch tests to (meth)acrylates considered to be probably relevant. All eight reacted to tetrahydrofurfuryl methacrylate, of whom five had a positive reaction to this hapten only. The other three all co-reacted to isobornyl acrylate and 1,6-hexanediol diacrylate. None had positive patch tests to hydroxyethyl methacrylate.

CONCLUSIONS

There are strong indications that tetrahydrofurfuryl methacrylate and isobornyl acrylate are relevant contact allergens present in hearing aid ear moulds. Hydroxyethyl methacrylate did not identify a single case of contact allergy to these materials.