Facial protective equipment, such as masks, place a significant amount of pressure on different facial areas, most notably the nasal bridge [13]. This can often cause numerous injuries at different facial points [14]. Pressure, friction and the hyperhydration effect caused by masks and goggles often result in skin indentation, mechanical skin damage, and epidermal barrier breakdown [12,15]. N95 masks specifically have increased air impermeability and a higher local pressure, increasing the risk of dermatological symptoms [7].

Risk factors for pressure damage are the following: prolonged wearing of personal protective equipment (PPE) [14-17], repeated wearing of PPE [15], use of grade 3 PPE [14], joint use of masks and goggles [7], high humidity [15], and heavy sweating [14]. Conflicting findings based on the relevance of gender and pressure-related injuries were reported in several studies [7,14,17].

Measures to reduce pressure-related injuries include the following: education of health care workers [7,17], wearing a properly fitted mask to minimize friction at specific points [7,11], regular moisturizing before and after the use of facial protective equipment for skin barrier repair [6,7,11,16], and limiting the time spent using a mask; published guidelines suggest limiting mask-wearing to 2 hours [6,11,13,16].

Pressure-related injuries that are progressive or cause discomfort to the user may be relieved by the use of a hydrocolloid dressing [6,16-18]. Hydrocolloid dressings are composed of water, sodium polyacrylate, cellulose gum, and sodium hyaluronate; these components serve as a cushion for soft tissue, thus reducing pressure and retaining skin moisture [18]. Dong et al [18] conducted a study to observe if hydrogel patches relieve skin damage in 19 health care workers; they reported that using hydrogel patches resulted in a lower mean score for skin reactions (3.47, SD 1.39, compared to nonuse scores of 13.32, SD 2.06), demonstrating that hydrogel patches are able to reduce the emergence and severity of skin damage [18]. Furthermore, they reported that the use of hydrogel patches reduced skin indentation as well as pain [18].

Conflicting evidence was reported on whether hydrocolloid dressings impacted the seal of facial masks [6,16,19].

High levels of humidity are reportedly a predisposing factor to skin barrier damage [15]; to reduce humidity levels, it is recommended to line masks with a paper towel or gauze [15].

ICD is a common problem reported by health care workers [7,17,20]; symptoms include burning, itching, and stinging [11]. Formaldehyde, a material used in both surgical and N95 masks, has been recognized to be a frequent contact sensitizer for many people [7,16]. Acute and chronic dermatitis may be a result of skin and mucus membrane damage [11]. Facial protective equipment may induce ICD through occlusion and friction from the mask and the hyper-hydration effect of PPE; in turn, this breaks down the epidermal barrier of the skin [20]. Factors that predispose individuals to ICD include the following: increased moisture, warm environments, occlusion due to local pressure, and friction [7,21].

Protective measures include the following: ensuring the proper fit of the mask, labeling of contact sensitizers on face masks [17], cooling the skin by ensuring adequate air conditioning at the site, and wiping skin to remove sweat at appropriate times [20]. Staff should limit the duration of mask-wearing by having rotating shifts and regular mask-free breaks [20]. Furthermore, staying hydrated may also reduce symptoms of dermatitis [20].

Treatment of ICD includes the use of emollients before wearing masks [11,20,22]; emollients should be applied at least 30 minutes before wearing the mask to prevent damage to the mask [20]. Staff may also choose to line the mask with gauze to reduce the humidity [11]. For moderate to severe ICD, topical glucocorticoids may be recommended [11,20,22].

Occupational ACD was also a common problem reported among health care workers [17]. ACD has a similar set of symptoms to ICD, which includes the following: pruritus, burning sensations, facial and periocular erythema, and subtle eczematous lesions [12,17]. Aggravating factors that may induce ACD include the following: prolonged use of PPE [7], increased moisture from perspiration, occlusion effects from the mask [7,23], friction [7,23], atopic predisposition [7], and contact sensitizers including formaldehyde [17,23]. Maliyar et al [23] reported that 22.8% of the population is sensitive to formaldehyde.

The gold standard for the diagnosis of ACD is patch testing [7].

The treatment for ACD is similar to that recommended for ICD. It is important to ensure correct fitting of PPE [23], the use of facial moisturizers before and after using PPE [11,23], the avoidance of facial cleansing with overheated water, 75% ethanol, or a facial cleanser [11], and the use of hydrogel dressings on damaged skin [23]. Layers of gauze inside the mask may be used to reduce moisture effects within the mask [11]. For mild dermatitis, the use of emollients is adequate; if the dermatitis progresses, topical glucocorticoid ointments may be used [11].

Retroauricular dermatitis is characterized by itching, redness, and scaling within the auricular region [24]. Ear pressure through the use of ear-hook masks is a reported cause of this type of dermatitis [15].

Recommendations to reduce dermatitis and ear pain include the following: the use of strings or hairpins to lengthen the ear-hook string [15] help reduce the tightness of masks [25]. Jiang et al [26] explored the use of a plastic handle to reduce ear pressure exerted by N95 masks; the advantage of this method was the simplicity of the idea and the increase in comfort on using the masks.

Pei et al [27] reported that 73.1% of participants developed skin lesions due to PPE in a cohort of 484 health care workers. Skin lesions included the following: erythema, prurigo, blisters, rhagades, papule, oedema, exudation, crusting, and lichenification [12,27]. The most common sites were the nasal bridge as well as the cheeks and forehead [12]. Factors attributed to skin lesions included the following: higher grades of PPE, higher working frequency within PPE, and prolonged use of PPE [9,25,27].

Measures to reduce the incidence of skin lesions include the following: wearing the mask correctly, taking mask-free breaks, and frequently replacing of protective gear [25].

In a sample of 542 participants in China, skin dryness was the most commonly reported symptom (70.3%) [9]. Closed humid environments, such as those resulting from breathing in masks and the use of PPE [9], result in skin barrier dysfunction [11,28]. Skin barrier dysfunction may consequently lead to skin dryness and scaling [11].

Management of skin dryness involves the use of high-potency moisturizers before and after PPE use [11].

Hua et al [29] reported increased erythema following PPE use; erythema results from cutaneous blood vessel dilation and increased blood supply to the skin [29]. Although this may be a normal reaction to heat and pressure, long-lasting erythema may be a sign of inflammation [29]. Significant differences between the use of N95 masks and surgical masks have been reported; N95 masks reportedly increase the facial temperature of the user and are perceived to be more uncomfortable [30]. Factors potentially causing skin erythema include long hours and prolonged mask-wearing [20]. Campbell et al [31] reported that skin erythema may progress to miliaria owing to the associations of immobility and humidity through prolonged mask-wearing.

Measures to reduce skin erythema include the following: limiting shift length [20], having mask-free breaks [20], and using a surgical mask rather than an N95 mask when appropriate [30].

Skin injury due to the use of disinfectants may result in ICD [32] and ACD [13]. Excessive stress among health care workers because of working with patients with COVID-19 may increase the frequency and duration of skin cleansing, which disrupts the skin barrier and inevitably leads to skin damage [13].

Although it is important to clean the face using soap-based cleansers after contact with patients with COVID-19 owing to the high risk of disease transmission, health care workers should be wary of excessive washing and the repeated application of disinfectants to the skin [13].

Skin and mucous membrane injury, through the disruption of the epidermal barrier, may lead to secondary infections [11]. Factors aggravating membrane injury include the following: prolonged mask-wearing resulting in a closed environment, compression, friction, and humidity [33].

Avoidance of PPE and the use of antihistamines and antibiotics are recommended for the treatment of secondary infections [13,33]. To prevent secondary infections, it is important to stop water from entering damaged skin; this can be done using waterproof plasters [33].

Flares of acne have been reported to result from the use of facial protective equipment; this is thought to be due to increased temperature and humidity caused by the mask [34]. High temperatures as well as high humidity facilitate the progression of acne due to bacterial proliferation and the portal occlusive effect of skin hydration and irritation to the upper parts of the pilosebaceous duct; in turn, this causes swelling of the epidermal keratinocytes, leading to acute blockage of the skin barrier [11,34]. Other underlying mechanisms potentially include pressure and friction [11]. Interestingly, Han et al [34] observed no correlation between acne severity and prolonged mask-wearing. Signs of acne include comedones, papules on the cheeks and nose, as well as nodules or cysts on the forehead, submaxillary, and neck region [34].

The management of acne vulgaris includes the following: liberal use of moisturizers before and after using facial protective equipment, topical antibiotic creams for mild papules and pustules, as well as topical retinoid creams for blackheads and whiteheads [11]. Cases of severe acne vulgaris should be referred to a dermatologist [11].

Navarro‐Triviño et al [35] found eczema to be one of the most frequently reported skin diseases associated with PPE use. The risk of eczema increased with continuous use of masks and protective glasses [32,35] as a result of increased heat owing to the closed environment, and increased stress [28].

Use of topical glucocorticoid creams or ointments is suggested for eczematous skin changes [13].

Rosacea has been frequently reported in association with PPE use [35]. Increased heat and stress is linked to the exacerbation of rosacea [28]. Prolonged PPE use is a risk factor for developing rosacea [32].

Urticaria of the face has been linked to the resulting vertical pressure of facial protective equipment [11]. Risk factors include the following: prolonged wearing of protective equipment and excessive personal hygiene [12].

Preventative measures include the use of correctly fitted protective equipment and antihistamines [11].

Yu et al [36] documented a case of impetigo due to occupational goggle-mask–wearing during the pandemic [36]. Increased humidity, skin trauma, and malnutrition can increase the skin’s vulnerability to infection and create a moist occlusive environment, allowing Staphylococcus aureus to grow and infect the damaged skin [36].

Management of this condition included rest away from PPE and the application of topical 2% fusidic acid cream twice daily [36].

Owing to occupational use of PPE, the nasal bridge was reported to be damaged in 83.1% of health care workers [37]. Pressure, friction, and the hyperhydration effect are known risk factors for ulceration [12,15.]

Hydrocolloid dressings may be of use to successfully treat nasal bridge ulceration [37].

Flares of pre-existing dermatoses have been reported to result from PPE use [17,28,32]. Stress, due to the pandemic, has been linked to the aggravation of skin conditions such as psoriasis, eczema, atopy, and neurodermatitis [28,32].

Zheng et al [32] questioned the use of psychological counseling to reduce the stress experienced by health care workers in order to reduce exacerbations of skin diseases.