Allergic contact dermatitis from the earmolds of hearing aids.

Hearing aid users with longstanding and severe dermatitis in the ear canal were examined by a dermatologist and patch tested. In 6 of 22 (27%) patients, contact allergy to the earmold material was found. Four of the six had a positive test reaction to methyl methacrylate and two also to triethyleneglycol dimethacrylate and urethane dimethacrylate. Positive patch test reactions to substances used for topical treatment were found as well. Routines including liberal patch testing for this group of patients are suggested.