key: cord-0967462-ytc6zb8u authors: Park, Sae‐Ra; Han, Jiyeon; Yeon, Yeong Min; Kang, Na Young; Kim, Eunjoo; SUH, Byung‐Fhy title: Long‐term effects of face masks on skin characteristics during the COVID‐19 pandemic date: 2021-10-19 journal: Skin Res Technol DOI: 10.1111/srt.13107 sha: d593815b3ad0ac145530c99e6ce3a898f4cc6a40 doc_id: 967462 cord_uid: ytc6zb8u BACKGROUND: Nowadays, face masks are a crucial part of our daily life. Previous studies on their impact on the skin usually focused on the adverse effects of face masks. Few studies have assessed their influence on skin characteristics. In a previous study, we identified the short‐term effects of wearing face masks. Herein, we describe the long‐term skin effects of face masks, for a period of 6 months. MATERIALS AND METHODS: Healthy volunteers (19 men and women), who wore face masks, participated in the study from June 2020 to December 2020. In all participants, skin characteristics such as trans‐epidermal water loss (TEWL), skin hydration, skin elasticity, skin pore area, skin keratin amount, skin temperature, skin redness, skin temperature, skin redness, and skin color were measured three times. RESULTS: TEWL, skin hydration, skin elasticity, skin pore area, skin keratin amount, and skin color changed significantly after 6 months. TEWL, skin hydration, skin pore area, skin keratin amount, and skin color were significantly different between the mask‐wearing and non‐mask‐wearing areas. CONCLUSION: Long‐term daily use of face masks can alter skin characteristics. Special care should be focused on the mask‐wearing regions. During the measurement period, we determined the type of masks that they used. Four types of masks were used: 1. surgical mask, 2. Korean filter-anti droplet (KF-AD) mask, 3. Korean filter 80 (KF80) mask, and 4. Korean filter 94 (KF94) mask. The types of masks usually worn are summarized in Table 1 . The grades and characteristics of each mask are listed in Table 2 . As the seasons and external environment changed from summer to fall to the beginning of the winter, the type of mask varied slightly. All participants were office workers. The average daily maskwearing time based on the 5 working days per week is listed in Table 3 . Depending on the coronavirus situation, the participants worked either at home or in the office. When participants worked at home, they did not wear masks. This explains the decrease in the mask-wearing time of the week. Before measurements, participants washed their faces and stayed in a controlled room with a room temperature of 22 ± 2 • C and relative humidity of 50 ± 5% to stabilize the skin. The areas measured for each skin characteristic are shown in Figure 1 . Mask-wearing regions include TEWL was measured on the forehead, cheeks, perioral area, and chin using a Vapometer (Delfin Technology Ltd, Kuopio, Finland). Skin hydration and skin elasticity were determined using Corneometer and Cutometer MPA580 devices (C+K, Köln, Germany), respectively. Skin hydration and skin elasticity measurements were performed on the forehead, cheeks, perioral area, and chin. Facial images for skin pore analysis were taken using VISIA-CR (CAN-FIELD, Fairfield, USA). Skin pore analysis was performed on the forehead, cheeks, and perioral area using the cross mode from VISIA-CR. Grade and characteristic of masks worn by the participants 6 Several filters in Image-Pro 10 software (Media Cybernetics, Silver Spring, USA) were used to emphasize the skin pores in the analysis area. The skin pore area (measured in pixels) was analyzed. Skin temperature was measured on the forehead, cheeks, perioral area, and chin using a thermal imaging camera (FLIR T640, Wilsonville, USA). Facial images were captured using VISIA-CR (CANFIELD, Fairfield, USA). Skin redness was analyzed on the forehead and cheeks using RBX red mode images from VISIA-CR. Skin color, lightness (L*), redness (a*), and yellowness (b*) were measured on the forehead and cheeks using a Spectrophotometer CM-2600d (Minolta, Japan). Statistical analyses were performed using SPSS Statistics 20 (IBM Corp., Armonk, NY, USA). The changes in skin characteristics from mask-wearing and non-mask-wearing areas were compared by RM-ANOVA. If normality was not satisfied, Friedman and Wilcoxon tests were used. Statistical significance was set at p < 0.05. From June to December, the TEWL of the mask-skin zone (mask- From June to December, the mask-skin zone had a decrease in skin From June to December, the skin elasticity of the cheeks, perioral area, and chin decreased by 14.54% (p < 0.001), 12.94% (p < 0.001), and 8.30% (p < 0.001), respectively. Meanwhile, the skin elasticity of the forehead decreased by 17.04% (p < 0.001) (Figure 4 ). From June to September, the skin elasticity of the cheeks and perioral area decreased by 7.75% (p < 0.001) and 6.38% (p < 0.001), respectively, while that of the chin increased by 2.14% (p < 0.01). In contrast, the skin elasticity of the forehead decreased by 8.26% (p < 0.001). From September to December, the skin elasticity of the cheeks, perioral area, and chin decreased by 7.36% (p < 0.05), 6.43% (p < 0.001), and 10.22% (p < 0.001), respectively. Meanwhile, the skin elasticity of the forehead decreased by 9.58% (p < 0.01). Compared to the forehead, the skin pore area of the cheeks was significantly different (p < 0.01) ( Figure 5 ). From June to December, the amount of skin keratin in the mask-skin zone increased. Skin keratin levels in the cheeks, perioral area, and From June to December, the skin temperature of the mask-skin zone significantly increased (1.25−2.35 • C). Skin temperatures of the cheeks, perioral area, and chin increased by 7.33% (p < 0.001), 3.71% (p < 0.001), and 3.79% (p < 0.001), respectively. The skin temperature of the forehead increased by 2.59% (p < 0.01). Compared to the forehead, the skin temperature of the cheeks (p < 0.001) and perioral areas (p < 0.05) were significantly different. From June to September, the skin temperature of the mask-skin zone significantly increased (0.88-0.72 • C). Skin temperatures of the cheeks, perioral area, and chin increased by 5.38% (p < 0.001), 2.69% (p < 0.01), and 2.63% (p < 0.01), respectively. The skin temperature of the forehead increased by 1.58% (p < 0.01). Compared to the forehead, the skin temperature of the cheeks was significantly different (p < 0.001). From September to December, the skin temperature of the cheeks increased by 1.86% (p = 0.03). The skin temperature of the forehead increased by 1.00% (p < 0.05). From June to December, the skin redness of the cheeks increased by From September to December, the skin redness of cheeks increased by 5.08% (p = 0.592). From June to December, skin color changes were variable. For the cheeks, skin redness increased by 13.08% (p < 0.001), while skin lightness and yellowness decreased by 1.49% (p < 0.01) and 6.99% From June to December, TEWL, a skin barrier-related indicator, changed greatly in the mask-skin zone compared to the non-mask-wearing area. In particular, the TEWL of the cheeks and perioral area showed a significant difference compared to the forehead (non-maskwearing area). Skin hydration of the mask-skin zone also decreased. The greatest change in skin hydration was in the perioral area likely due to its direct exposure to warm breath. Compared to the forehead, the mask-skin zones (cheeks, perioral area, and chin) were significantly different. Skin barrier function was weakened, and skin became dry at the same time. These changes would indicate deterioration in the skin condition. The mask-wearing areas are hot and humid, similar to the climate of a tropical rainforest. This implies that it is difficult to ventilate in these areas due to the occlusion effect of face masks. 9,10 This maskmicroclimate combined with rapid environmental changes caused by the repetition of wearing and taking off the mask was thought to have weakened the skin. In addition, the mask-skin zone exposed to warm body temperature breath showed a significant difference from the nonmask-wearing area. 11 From June to December, the amount of skin keratin also increased in the mask-skin zone. Skin keratin amount in the cheeks, perioral area, and chin significantly increased and showed a significant difference compared to the keratin amount in the forehead. The amount of keratin on the forehead also significantly increased, but the rate was lower than that in the mask-skin zone. The measurement period included both the summer and fall, which is a typical period when the skin begins to dry out. 12, 13 The change in skin keratin amount in the mask-skin zone was higher than that in the non-mask-wearing area. This was thought to be affected by the mask-microclimate due to the reduction in skin hydration, and this mask-microclimate might have led to significant differences between the mask-skin zone and non-mask-wearing area. Increased skin keratin amount might be a result of accumulating of dead skin cells or more easily exfoliating. This result also could be associated with changes in skin health, 14 such as skin dryness or weakening of skin barrier. The skin pore area was measured on the mask-skin zones (e.g., cheeks and perioral areas) and non-mask-wearing area (i.e., forehead). From June to December, the skin pore area of the mask-skin zone significantly increased. Although the skin pore area of the forehead also increased, the difference was not significant. Compared to the forehead, the skin pore area of the cheeks was significantly different. Skin elasticity significantly decreased in both the mask-skin zones and the non-mask-wearing area. These may be due to endogenous aging or stress 15 The skin color was expected to decrease the lightness of the nonmask-wearing area because the mask-skin zone was covered with a mask, while the non-mask-wearing areas were exposed to ultraviolet the cheeks that may cause physical irritation and redness. 16 In addition, the skin microclimate 17 caused by mask-wearing may also play a role. The lightness and yellowness of the skin may also be affected by maskwearing; however, the exact mechanism is unclear. Skin temperature and skin redness showed a significant change after wearing masks for a short period. 5 However, these changes were relatively small in this long-term study. It is thought that these two measurements are highly related to the homeostasis of body temperature. Although temporary changes are possible, chronic changes in baseline may be difficult to achieve. In this study, we analyzed skin changes during the 6-month period of wearing a mask continuously and daily. Skin changes caused by long-term wearing of masks were associated with skin barrier-related changes and dryness. In the mask-skin zone, TEWL (a skin barrier indicator) increased, but skin hydration decreased. These changes in TEWL and skin hydration were thought to be related to the increased skin keratin amount and skin pore area. Moreover, these may also influence the reduction in skin elasticity of the mask-skin zone as it weakened and dried from baseline (Table 4 ). Wearing masks daily is no longer limited to specific occupational environments due to the pandemic. In response to wearing masks, the human skin does not change easily because it tries to maintain homeostasis. However, there is a possibility that skin changes slowly in the long run. In this study, we evaluated the effects of long-term wearing of masks on facial skin. There were limitations in that we did not have skin measurement data without a mask at the same time in every subject. Moreover, seasonal changes may have also influenced the results. However, these seasonal changes vary in characteristics and aspects, while our results show that mask-skin zones had similar changes in each area, these changes were significantly different compared to nonmask-wearing areas. To confirm the clear etiology, further studies are needed in comparison to skin changes during periods without a mask. This paper highlights the changes in skin characteristics of the maskskin zones caused by the long-term wearing of masks. It is, hence, crucial that special care should be focused on the mask-skin zones. 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COVID-19, face masks and skin damage Microclimate: a critical review in the context of pressure ulcer prevention Long-term effects of face masks on skin characteristics during the COVID-19 pandemic The authors sincerely thank all members of the Clinical Research Lab for their invaluable assistance. Eunjoo Kim Ph.D. https://orcid.org/0000-0002-3032-5303