How irritant are n-propanol and isopropanol? - A systematic review

Background: The use of alcoholic-based hand rubs (ABHRs) is an important tool for hand hygiene, especially in times of the COVID-19 pandemic. Possible irritant effects of ABHR may prevent their use by persons at risk of infection.

Methods: This systematic review is based on a PubMed search of articles published between January 2000 and September 2019 in English and German, and a manual search, related to the irritation potential of alcohol-based disinfectants restricted to n-propanol (1-propanol) and its structural isomer isopropanol (isopropyl alcohol, 2-propanol).

Results: The majority of the included studies show a low irritation potential of n-propanol alone. However, recent studies provide evidence for significant barrier damage effects of repeated exposure to 60% n-propanol in healthy, as well as atopic skin in vivo. The synergistic response of combined irritants, (ie, a combination of n-propanol or isopropanol with detergents such as sodium lauryl sulfate) is greater, compared with a quantitatively identical application of the same irritant alone.

Conclusion: While recent studies indicate a higher risk of skin irritation for n-propanol and isopropanol than reported in the past, this risk still seems to be lower than that for frequent handwashing with detergents, as recommended by some to prevent COVID-19 infections.