The role of acrylic acid impurity as a sensitizing component in electrocardiogram electrodes.

Background. Allergic contact dermatitis caused by (meth) acrylates is well known, both in occupational and in non-occupational settings. Contact hypersensitivity to electrocardiogram (ECG) electrodes containing (meth) acrylates is rarely reported. Objective. To report the first case of contact dermatitis caused by acrylic acid impurity in ECG electrodes. Materials and methods. Patch tests were performed with separate components of electrodes and some (meth) acrylates. This was followed by high-performance liquid chromatography of electrode hydrogel. Results. The patient was contact-allergic to electrode hydrogel but not to its separate constituents. Positive reactions were observed to 2-hydroxyethyl methacrylate (2-HEMA), 2-hydroxypropyl methacrylate (2-HPMA) and ethyleneglycol dimethacrylate (EGDMA). Subsequent analysis showed that the electrode hydrogel contained acrylic acid as an impurity. The latter was subsequently patch tested, with a positive result. Conclusion. The sensitization resulting from direct contact with ECG electrodes was caused by acrylic acid, present as an impurity in ECG electrodes. Positive reactions to 2-HEMA, 2-HPMA and EGDMA are considered to be cross-reactions.