barrier function to epidermal pigmentation is thought to have emerged with evolution to ensure human survival in Africa where ambient humidity was in decline and where there is high exposure to ultraviolet B (UVB).11
In a study comparing African American, Hispanic, and Caucasian skin, ceramide levels were found to be highest in Asian skin, followed by Caucasian and Hispanic skin, and lowest in African American skin.12 In addition, the study also showed that Asian skin had more water content than Caucasian and African American skin. This is supported by other evidence that African American skin is more prone to dryness,8 suggesting that this may be as a result of the lipid differences between the ethnic backgrounds. Similar results showing lower ceramide to protein ratio have also been reported in comparison to Caucasian and Asian skin.13 From these findings, it is clear that enhancing the lipids and especially ceramide levels in the skin can help in the recovery of barrier function and increased water content in the SC.
Skin Barrier Disorders in Diverse Populations
The skin barrier is impaired or dysfunctional in some skin conditions such as atopic dermatitis (AD), psoriasis, xerosis, ichthyosis, and in diabetetics.14 The compromised skin barrier leads to excess loss of water, increased pH, susceptibility to infection, and accelerated penetration of antigens and microbes, which cause contact sensitization and inflammation.15 Without repair to the compromised barrier, clinical signs of barrier disruption become more evident and progressive, which presents as increased desquamation, clumping of corneocytes leading to scaling, flaking, and decrease in elasticity, therefore causing cracking of the skin and hyperkeratosis as a hallmark of increased keratinocyte proliferation.16 These can cause the skin to be cosmetically disfigured or unappealing, which creates social stigma, increased anxiety, and social distress in affected individuals.
Skin barrier disorders show differences in prevalence and manifestations in different skin types. AD is the most common, representative skin barrier disease affecting 3–10% of the population, globally.17 AD has been shown to be 1.7 times more prevalent in African Americans than Caucasians, even with adjustment of social economic factors and environment.18 Additionally, Africa and Oceania show higher rates of AD than India and Northern and Eastern Europe.19 Evidence shows that there is a genetic component to AD with genome-wide association studies identifying 31 risk loci with ethnic variations between African, Hispanic, Asian, and Caucasian patients.20
COVID-19 in Dermatology and Barrier Disruption
The severe acute respiratory syndrome coronavirus 2 (SARSCoV- 2), which causes the novel coronavirus disease COVID-19, emerged in 2019 as a global healthcare threat. While initially presenting as a disease of the lower respiratory system, it is now known to be asymptomatic or symptomatic affecting the gastro-intestinal, cardiovascular, neurological, and dermatological systems, and can result in multi-system inflammatory syndrome in children.21,22 Various dermatological conditions associated with COVID-19 have been noted such as pernio-like inflammatory skin reactions consisting of red or purple itchy bumps on the toes, heels, or fingers commonly referred as “COVID toesâ€, measles-like rashes – morbilliform exanthema, chilblains, erythematous macules, or papules and petechial eruptions (Freeman et al 2020). Differences in manifestation of COVID-19 cutaneous diseases vary with skin color and it is especially apparent that darker skin types are challenging in examination and diagnoses of erythema and pernio-like lesions, which can lead to inaccurate diagnosis.
Protective measures against COVID-19 include frequent hand washing and use of personal protective equipment (masks, gloves, shields, eye wear) leading to a high prevalence of occupational dermatoses among healthcare workers and in the general population.23 Frequent handwashing has been reported to cause xerosis, irritant contact dermatitis, and even allergic contact dermatitis, as a result of frequent exposure to water, soaps, detergents that strip the skin of lipids, and use of hand sanitizers with high alcohol content.24 Recommendations to alleviate xerosis and hand dermatitis include liberal application of moisturizers and ointments after handwashing and especially those that contain humectants such as urea, occlusive emollients, such as petrolatum, lanolin, and vegetable oils, or physiological lipids such as ceramides that replenish the depleted skin lipids and prevent dehydration.25 Additionally, mask usage has been reported to exacerbate acne flare ups. This type of acne, acne mechanica or “maskneâ€, is multifactorial and occurs as a result of the mechanical insult to the skin barrier, increased sweating causing a buildup in humidity and blockage in the pilosebaceous unit, with symptoms that include burning, itching, and scratching, which can reduce the efficacy of mask wearing.26 With dermatologists increasingly seeing patients with acne mechanica, the recommendations have been to wear properly fitting masks, wash reusable masks often, use mild cleansers that are gentle on the skin, and use non-comodogenic moisturizers.27
Sensitive Skin
Sensitive skin is a complex problem with genetic, individual, environmental, occupational, and ethnic implications. “The role of biological (ethnic differences), social, economic, and psychological (ethnic variations) factors for the skin sensitivity are reflected in the concept of 'ethnic sensitive skin'â€.28
Although initially believed to be an unusual reaction to common products, evidenced in only a small subset of consumers, epidemiological surveys surprisingly found a high prevalence
In a study comparing African American, Hispanic, and Caucasian skin, ceramide levels were found to be highest in Asian skin, followed by Caucasian and Hispanic skin, and lowest in African American skin.12 In addition, the study also showed that Asian skin had more water content than Caucasian and African American skin. This is supported by other evidence that African American skin is more prone to dryness,8 suggesting that this may be as a result of the lipid differences between the ethnic backgrounds. Similar results showing lower ceramide to protein ratio have also been reported in comparison to Caucasian and Asian skin.13 From these findings, it is clear that enhancing the lipids and especially ceramide levels in the skin can help in the recovery of barrier function and increased water content in the SC.
Skin Barrier Disorders in Diverse Populations
The skin barrier is impaired or dysfunctional in some skin conditions such as atopic dermatitis (AD), psoriasis, xerosis, ichthyosis, and in diabetetics.14 The compromised skin barrier leads to excess loss of water, increased pH, susceptibility to infection, and accelerated penetration of antigens and microbes, which cause contact sensitization and inflammation.15 Without repair to the compromised barrier, clinical signs of barrier disruption become more evident and progressive, which presents as increased desquamation, clumping of corneocytes leading to scaling, flaking, and decrease in elasticity, therefore causing cracking of the skin and hyperkeratosis as a hallmark of increased keratinocyte proliferation.16 These can cause the skin to be cosmetically disfigured or unappealing, which creates social stigma, increased anxiety, and social distress in affected individuals.
Skin barrier disorders show differences in prevalence and manifestations in different skin types. AD is the most common, representative skin barrier disease affecting 3–10% of the population, globally.17 AD has been shown to be 1.7 times more prevalent in African Americans than Caucasians, even with adjustment of social economic factors and environment.18 Additionally, Africa and Oceania show higher rates of AD than India and Northern and Eastern Europe.19 Evidence shows that there is a genetic component to AD with genome-wide association studies identifying 31 risk loci with ethnic variations between African, Hispanic, Asian, and Caucasian patients.20
COVID-19 in Dermatology and Barrier Disruption
The severe acute respiratory syndrome coronavirus 2 (SARSCoV- 2), which causes the novel coronavirus disease COVID-19, emerged in 2019 as a global healthcare threat. While initially presenting as a disease of the lower respiratory system, it is now known to be asymptomatic or symptomatic affecting the gastro-intestinal, cardiovascular, neurological, and dermatological systems, and can result in multi-system inflammatory syndrome in children.21,22 Various dermatological conditions associated with COVID-19 have been noted such as pernio-like inflammatory skin reactions consisting of red or purple itchy bumps on the toes, heels, or fingers commonly referred as “COVID toesâ€, measles-like rashes – morbilliform exanthema, chilblains, erythematous macules, or papules and petechial eruptions (Freeman et al 2020). Differences in manifestation of COVID-19 cutaneous diseases vary with skin color and it is especially apparent that darker skin types are challenging in examination and diagnoses of erythema and pernio-like lesions, which can lead to inaccurate diagnosis.
Protective measures against COVID-19 include frequent hand washing and use of personal protective equipment (masks, gloves, shields, eye wear) leading to a high prevalence of occupational dermatoses among healthcare workers and in the general population.23 Frequent handwashing has been reported to cause xerosis, irritant contact dermatitis, and even allergic contact dermatitis, as a result of frequent exposure to water, soaps, detergents that strip the skin of lipids, and use of hand sanitizers with high alcohol content.24 Recommendations to alleviate xerosis and hand dermatitis include liberal application of moisturizers and ointments after handwashing and especially those that contain humectants such as urea, occlusive emollients, such as petrolatum, lanolin, and vegetable oils, or physiological lipids such as ceramides that replenish the depleted skin lipids and prevent dehydration.25 Additionally, mask usage has been reported to exacerbate acne flare ups. This type of acne, acne mechanica or “maskneâ€, is multifactorial and occurs as a result of the mechanical insult to the skin barrier, increased sweating causing a buildup in humidity and blockage in the pilosebaceous unit, with symptoms that include burning, itching, and scratching, which can reduce the efficacy of mask wearing.26 With dermatologists increasingly seeing patients with acne mechanica, the recommendations have been to wear properly fitting masks, wash reusable masks often, use mild cleansers that are gentle on the skin, and use non-comodogenic moisturizers.27
Sensitive Skin
Sensitive skin is a complex problem with genetic, individual, environmental, occupational, and ethnic implications. “The role of biological (ethnic differences), social, economic, and psychological (ethnic variations) factors for the skin sensitivity are reflected in the concept of 'ethnic sensitive skin'â€.28
Although initially believed to be an unusual reaction to common products, evidenced in only a small subset of consumers, epidemiological surveys surprisingly found a high prevalence
