Compromised skin barrier induced by prolonged face mask usage during the COVID‐19 pandemic and its remedy with proper moisturization

BACKGROUND: Prolonged face mask usage, a daily practice for the public due to the COVID‐19 pandemic, creates high levels of humidity underneath the mask, which may cause unexpected skin concerns. OBJECTIVE: To investigate the impact of repeated mask usage on the face by comparing skin properties inside and outside of the mask‐covered areas. METHODS: A double‐blinded, randomized, split‐face clinical study was conducted with 21 healthy female participants who wore face masks at least 6 h every day for 1 week, with one side of their face treated with a moisturizer three times daily. On day 8, after 5 h of wearing the mask, skin properties (sebum, hydration, and trans‐epidermal water loss [TEWL]) were evaluated at 15, 60, and 120 min post‐mask removal, followed by barrier disruption and recovery assessment. RESULTS: Mask usage weakened stratum corneum (SC) on facial skin compared to uncovered areas, including reduced SC hydration (p < 0.02 at 15 min) and increased TEWL in response to tape stripping challenge (p < 0.03 after stripping). In addition, sebum production also increased after mask removal (p < 0.01 at 15 min). Notably, a daily moisturizer mitigated these effects by increasing SC hydration (p < 0.001) and improving SC resilience against barrier disruption. CONCLUSION: Daily prolonged usage of a facial mask, essential due to the COVID‐19 situation, generated a high‐humidity microenvironment and led to compromised SC, which was revealed by a barrier challenge technique. Moreover, proper facial moisturization may help to maintain skin homeostasis and prevent the barrier impairment caused by repeated mask usage.