Effects of skin washing frequency on the epidermal barrier function and inflammatory processes of the epidermis: An experimental study

Background: Increased hand hygiene measures during the COVID-19 pandemic have led to an increased quantum of hand eczema (HE). Objectives: To examine the effects of varying washing frequencies using current mild cleansing agents—alongside with the effect of a rehydrating cream—on the epidermal barrier function and inflammatory processes of the stratum corneum(SC). Methods: Standardized skin washings on the volar aspects of the lower arms of skin-healthy volunteers were performed using the automated cleansing device either 5 or 11 times within 4 h for 60 s each with a standard cleanser, a lipid-containing syndet, or a lipid-containing syndet followed by one-time application of a rehydrating cream. Skin bioengineering parameters (transepidermal water loss, SC hydration, erythema, and SC pH) and biochemical/immunological parameters (interleukin-1α, interleukin-1α receptor antagonist and natural moisturizing factor) of SCsamples collected by tape stripping were assessed. Results: All applied washing procedures provided comparable, mild effects on the epidermal barrier function and skin inflammation. Conclusion: Occupational skin cleansers seem to have improved regarding skin barrier damaging effects. To further corroborate this, a study design, modified on the basis of our findings, applying longer washing periods for consecutive days seems desirable.