ABSTRACT
Background: During the beginning of the COVID-19 pandemic many healthcare workers (HCW) reported skin irritation when using alcoholic hand disinfectants (AHD), often based on WHO-recommended formulation, from temporary manufacturers. Apart from eczema, some HCW also reported erythema and burning sensation within 10-30 minutes after application of AHD. This was not experienced with regular AHDs. The culprit AHDs had an unpleasant smell which made us investigate aldehydes as a possible cause. Objectives: Investigate skin reactions to aldehydes. Methods: 4 HCWs were investigated with 15 minutes exposure (closed test) for immediate reactions to AHD and acetaldehyde. Based on the literature a test dose of 10% acetaldehyde was used. Later, chemical analyses for aldehydes were made, and closed test with dilution series of acetaldehyde were performed in healthy volunteers. Results: All HCWs were positive to acetaldehyde 10%. Levels of 0.25-1.9 ppm of acetaldehyde were detected in regular AHDs, compared to 80-800 ppm in the culprit AHDs. In test tubes addition of hydrogen peroxide to ethanol enhances acetaldehyde formation. In volunteers 10/10 reacted to acetaldehyde 10%, and 6/10 to 3.3%. Conclusions: Hydrogen peroxide included in the WHO-recommended AHD is oxidizing ethanol to acetaldehyde and elevated levels of acetaldehyde were detected in AHDs causing skin complaints. Acetaldehyde can cause erythema, although at single application on intact skin, higher doses than those found in the AHDs are needed. However, AHDs are used repeatedly on skin where the skin barrier function could be reduced by repeated hand washing. Therefore, acetaldehyde-rich AHDs as a cause to skin reactions cannot be ruled out.