Efficacy of a moisturizing cream and facial mask for alleviating skin problems associated with medical mask use: A half‐face, randomized controlled study

Prolonged use of medical masks has increased skin‐related issues.


| INTRODUC TI ON
The coronavirus disease 2019 (COVID-19) pandemic necessitated the use of medical masks as a primary preventive measure to halt the transmission of viral droplets. 1Mask use remains an effective way to prevent COVID-19 and other respiratory diseases in the postpandemic era.Certain occupations, such as healthcare workers, require prolonged daily use of medical masks.Previous studies have reported an increase in skin problems associated with long-term use of medical masks. 2,3A Chinese expert consensus has identified several potential dermatological issues that can arise due to prolonged mask usage, including physical pressure damage to local skin, urticaria, contact dermatitis, and exacerbated symptoms of pre-existing skin conditions such as eczema and acne. 4ysical pressures exerted by the medical mask can lead to local skin indentations and may even impact tissue microcirculation, resulting in severe pressure injuries. 5Wearing the masks also creates a high temperature and humidity microclimate around the skin.This enclosed environment can lead to overhydration of the stratum corneum, damaging the skin barrier and potentially prompting irritation and allergic reactions to mask components. 1,6In addition, it can facilitate the proliferation of microorganisms such as Cutibacterium acnes, further aggravating acne conditions. 1,7Our preliminary, unpublished, randomized controlled trial involving 20 healthy Chinese female subjects found that wearing a medical mask for 4 h led to an internal temperature rise of 4.06°C and a humidity reaching 94.0% within the mask.Compared to the adjacent day without wearing medical masks, the subjects' skin surface temperature was 1.24°C higher and their transepidermal water loss (TEWL) was elevated by 18.1% (corresponding to 3.01 g/m 2 •h) instantly after removal of medical mask.Previous clinical trials support these findings. 3Thus, continuous attention to the dermatological consequences of mask usage is warranted.
A Chinese expert consensus recognizes the potential utility of moisturizing and barrier-repair skincare products in addressing the dermatological issues. 4These interventions can lubricate the skin to minimize friction, while also offering a proactive and restorative response to dryness, desquamation symptoms, and skin barrier damage. 1,4,8In a previous randomized half-face clinical study on 21 healthy female participants who wore masks for at least 6 h each day for a week, regular application of a moisturizer helped maintain skin homeostasis and prevent the skin barrier impairment associated with mask usage. 9Similarly, a study involving 20 healthy Korean women with sensitive skin found that mask usage induced physiological changes in the skin, but these conditions improved with the application of a moisturizer post-mask removal. 10wever, existing research into the effectiveness of such skincare solutions among healthy Chinese subjects is limited.This dearth of evidence inspired our investigation into the effects of a moisturizing facial cream and a facial mask on skin problems caused by prolonged medical mask usage.By extending these findings to the Chinese context, our study seeks to substantiate the prophylactic and curative potential of these skincare products in maintaining skin health amidst the ongoing necessity of medical mask usage.This study was approved by Shanghai Ethics Committee (approval number: SECCR/2021-9-1).All subjects provided written informed consent before enrollment.

| Grouping and blinding
The 64 subjects were randomly divided into two groups, namely the facial cream group and the combined use group, each comprising 32 individuals.Subjects were aware of the grouping as the procedures were clearly different.The dermatologist who performed the clinical assessment was blind to grouping.

| Intervention
The study's procedural conditions were maintained at a consistent temperature (21 ± 1°C) and humidity (45 ± 5%) throughout its duration.Following a thorough facial cleansing and a rest period of 30 min, all subjects wore medical masks for 4 h (T b ).Upon mask removal, subjects in the facial cream group applied the test facial cream on a randomly selected half of their face, with a dosage of 2 mg/cm 2 , leaving the contralateral half untreated.A waiting period of 10 min ensued prior to examination (T 1 ).Simultaneously, the combined use group initially applied the tested facial mask, cut from the midline, to a randomly selected half of their face.After 15 min, the mask was removed, followed by a rest period of 1 h (T 2 ).
Subsequently, the test facial cream was applied to the same half face at a dosage of 2 mg/cm 2 , with a further 10 min wait before examination (T 3 ).The contralateral half of the face remained untreated for this group as well.
Both the facial cream and mask contained madecassoside, panthenol, and thermal water, and the facial cream additionally contained microelements such as copper, zinc, and manganese.During the study, subjects were brand blind to both test products.

| Assessments and outcomes
Three key metrics, TEWL, skin dryness scores, and the area of skin redness were assessed at T b and T 1 for the facial cream group and at T b , T 2 , and T 3 for the combined use group.TEWL was measured using the Tewameter® TM300 instrument (Courage & Khazaka, Germany).Skin dryness was scored by the same dermatologist on a scale of 0-9, based on skin imaging conducted with Dermascore 11 (Monaderm, Monaco).Higher scores indicated greater skin dryness.
The skin redness area was determined through facial imaging using VISIA-CR® (Canfield, USA), and subsequent image analysis with Image-Pro-Plus® (Media Cybernetics, USA).

| Statistical analysis
Statistical analyses were conducted using SPSS version 25.0 (IBM Co., Armonk, NY, USA).For the facial cream group, changes in the outcomes from T b to T 1 were analyzed and compared between the treated and untreated half-faces.For the combined use group, changes in the outcomes from T b to T 2 and from T b to T 3 were analyzed and compared between the treated and untreated halffaces.Since the outcomes were continuous variables, data were expressed as means ± standard deviations and compared using the paired t-test.A p < 0.05 was considered to denote statistical significance.

| Baseline characteristics
All the 64 subjects enrolled completed the study process.The mean ages for the facial cream group and the combined use group were 36.28 ± 4.14 and 34.53 ± 5.27 years, respectively.Notably, 50% (16/32) of the subjects in each group reported having sensitive skin.
Figure 1 presents a typical case in the facial cream group with remarkable improvement in skin redness area, reducing from 85.67% at T b to 77.67% at T 1 .

| Efficacy of the combined use of the test facial cream and facial mask
In the combined use group, significant improvements were observed in TEWL (20.62 ± 0.76 and 19.41 ± 0.76 vs. 24.08 ± 0.76 [T b ] g/h cm 2 ), skin dryness score (4.94 ± 0.25 and 4.63 ± 0.26 vs. 5.56 ± 0.25 [T b ]), and redness area (41.23 ± 0.06% and 41.63 ± 0.06% vs. 55.48 ± 0.06% [T b ]) at T 2 and T 3 compared to T b on the treated half-face (all p < 0.05).Notably, the combined use of the facial mask and cream led to significantly lower TEWL at T 3 compared to the use of the facial mask alone at T 2 (p < 0.05).On the untreated half-face, the redness area was reduced at T 2 (41.86 ± 0.06%) and T 3 (40.84± 0.06%) compared to T b (54.69 ± 0.06%) (both p < 0.05), while TEWL and skin dryness score were generally similar, except that skin dryness score reduced from 5.44 ± 0.24 at T b to 5.25 ± 0.25 at T 3 .
Compared to the untreated half-face, the application of the facial mask alone at T 2 and the combination of the facial mask and cream at T 3 resulted in significantly better improvements in TEWL (T 2 , −3.46 ± 0.33 vs. −0.09± 0.13 g/h cm 2 ; T 3 , −4.67 ± 0.31 vs. −0.28± 0.22 g/h cm 2 ) and skin dryness score (T 2 , −0.63 ± 0.13 vs. 0.03 ± 0.03; T 3 , −0.94 ± 0.17 vs. 0.19 ± 0.07) (all p < 0.001).No significant difference was observed regarding the reduction in redness area (Table 2).Prolonged use of medical masks results in a notable rise in temperature and humidity inside the mask, leading to a significant increase in skin surface temperature. 1,6Upon removal of the mask, rapid evaporation of accumulated moisture on the skin occurs, triggering extensive water loss, and consequently leading to dehydration of the stratum corneum. 12,13This effect disrupts the skin's barrier function, potentially culminating in skin dryness, and desquamation.Concurrently, prolonged mask usage prompts a trend toward reddening of the skin. 13,14is is primarily due to the elevation in skin temperature, which stimulates the thermoregulatory mechanisms, causing skin blood vessels to dilate, and blood flow to increase. 15,16Although these effects generally revert to normal post-mask removal, persistent erythema may ensue in cases of extended mask wear due to inflammatory responses. 3,17 the present study, the facial cream and mask utilized are abundant in moisturizing and barrier repairing ingredients that confer a myriad of benefits to the skin.For instance, madecassoside can notably enhance skin hydration and moisturization both in vitro and in vivo, proving to be both medically and cosmetically beneficial. 18 addition, panthenol, a derivative of provitamin B5, is highly effective in moisturizing, reducing inflammation, and promoting healing, which plays a crucial role in strengthening the skin's barrier function and significantly enhancing the hydration levels of the stratum corneum. 19,20Moreover, the trace elements of copper, zinc, and manganese, have been shown to expedite barrier healing by modulating keratinocyte migration and integrin expression. 21r findings revealed that compared to the state immediately post-mask removal or a control group not utilizing skincare products, the application of the test facial mask, facial cream, or their combination could significantly ameliorate skin barrier damage and dryness symptoms.Intriguingly, the improvement in damaged skin barrier function was more pronounced when using the test facial cream and facial mask, as opposed to using the facial mask alone.
In addition, the treated half-faces tended to achieve a numerically larger decrease in redness area compared to the untreated half-faces in both groups, and the lack of statistical significance was probably because that the redness mainly resulted from transient elevation  in skin temperature instead of inflammatory erythema.Still, the use of the skincare product, particularly the facial mask, can induce a cooling and soothing sensation, especially beneficial when the skin feels hot and uncomfortable.Individuals mandated to don medical masks daily may benefit significantly from regular application of the tested facial cream due to its continued soothing and repairing effects on the facial skin.Furthermore, those with an impaired facial skin barrier function and exacerbated dryness symptoms can avail of an added rapid repair effect from using the facial mask.For the inflammatory erythema associated with long-term medical mask wearing, the anti-inflammatory and repairing ingredients may exert a mitigating effect. 21These results underscore the potential utility of these skincare products in mitigating skin issues induced by sustained medical mask wear.
This study, while providing initial insights into the potential benefits of a facial cream and mask in mitigating skin problems caused by long-term use of medical masks, bears several limitations.First, subjects were aware of the grouping due to the evidently different procedures.However, the outcome measures were either objective or conducted by a dermatologist who did not know the grouping, and thus the potential bias in results were quite small.Second, our study focused on the short-term effects of a facial cream and mask in alleviating skin issues from medical mask use, whereas other studies have focused on the effects of creams over a relatively longer period of time than our study. 9,10Third, although our sample size is relatively large compared to previously published studies, 9,10 future research should involve larger-scale studies with longer durations of use and follow-up to provide a more comprehensive evaluation of the long-term efficacy.
In summary, our study provided empirical evidence that both the test facial cream and mask significantly ameliorated the symptoms of impaired skin barrier function and dryness associated with prolonged medical mask usage.Importantly, a superior improvement was noted when the two products were used in conjunction.These findings underscore the potential utility of these skincare products in managing mask-related skin complications, particularly in the current era where medical mask usage is prevalent due to public health mandates.The issue remains relevant in the post-pandemic era, since people still wear medical masks in daily life, especially in public places and on transportation.

AUTH O R CO NTR I B UTI O N S
Yang Wang had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.Chengda Ye and Yan Wu were involved in the study concepts and design.All authors were involved in the interpretation of data.Yang Wang and Yueqing Niu were involved in the draft of the manuscript.All authors read, critically revised, and approved the manuscript.

FU N D I N G I N FO R M ATI O N
This study was funded by L'Oreal.

A
total of 64 healthy Chinese female volunteers were recruited in February 2021 at Shanghai China-Norm Quality Technical Service Co., Ltd.Eligible subjects were women aged 18-40 years, presenting with bilateral facial TEWL levels greater than or equal to 15 g/ m 2 h.The exclusion criteria encompassed any individual with facial or skin conditions, as well as systemic or visceral diseases that, rendered them unsuitable for participation in this study, as determined by the researchers.Importantly, our recruitment strategy aimed to include half of the subjects self-identifying as having sensitive skin.

TA B L E 1
Transepidermal water loss (TEWL), skin dryness score, and redness area before and after use of the test cream in the facial cream group (n = 32).0.05 vs. T b .

F I G U R E 1 A
typical case who achieved remarkable improvements from T b (A) to T 1 (B) in skin redness area in the facial cream group.T b , the moment after wearing medical masks for 4 h; T 1 , 10 min after using the facial cream.TA B L E 2Transepidermal water loss (TEWL), skin dryness score, and redness area before and after using the facial cream and facial mask in the combined use group (n = 32).