A Time-Series Study of the Effect of Air Pollution on Outpatient Visits for Acne Vulgaris in Beijing

Global, regional, and national levels and trends in burden of urticaria: A systematic analysis for the Global Burden of Disease study 2019

Background

Urticaria places a significant burden on individuals and society due to its widespread nature. The aim of this study was to evaluate the burden of urticaria in different regions and nations by analysing data from the Global Burden of Disease study 2019 (GBD 2019), with the goal of providing information to health care policymakers.

Methods

By utilising data from the GBD 2019 database, this study analysed metrics such as incidence, prevalence, disability-adjusted life years (DALYs), age-standardised rate (ASR), and estimated annual percentage changes (EAPC) globally and across 204 countries and regions. The data was further stratified by age, sex, and sociodemographic index (SDI).

Results

In 2019, global incidence cases, prevalence cases, and overall disease burden as measured by DALYs all increased. The distribution of the burden exhibited marked geographical heterogeneity. At the regional level, the burden is highest in Central and Eastern Europe and Central Asia, with the strongest growth in South Asia, compared with a decline in the high-income Asia Pacific. At the country level, Nepal reports the highest burden of urticaria, while Portugal has the lowest. Gender and age analyses showed that the burden of urticaria is higher in females than in males, with urticaria cases declining with age, especially in children, and picking up among the elderly. The study also finds a correlation between the burden of urticaria and the SDI, with the central part of the SDI showing a consistent increasing trend.

Conclusion

This study found that the global burden of urticaria has risen from 1990 to 2019. Factors like geographic location, gender, and SDI influenced the urticaria burden. Overall, these results offer a resource to guide public health strategies seeking to reduce the burden of urticaria.

Environmental Air Pollutants Affecting Skin Functions with Systemic Implications

The increase in air pollution worldwide represents an environmental risk factor that has global implications for the health of humans worldwide. The skin of billions of people is exposed to a mixture of harmful air pollutants, which can affect its physiology and are responsible for cutaneous damage. Some polycyclic aromatic hydrocarbons are photoreactive and could be activated by ultraviolet radiation (UVR). Therefore, such UVR exposure would enhance their deleterious effects on the skin. Air pollution also affects vitamin D synthesis by reducing UVB radiation, which is essential for the production of vitamin D3, tachysterol, and lumisterol derivatives. Ambient air pollutants, photopollution, blue-light pollution, and cigarette smoke compromise cutaneous structural integrity, can interact with human skin microbiota, and trigger or exacerbate a range of skin diseases through various mechanisms. Generally, air pollution elicits an oxidative stress response on the skin that can activate the inflammatory responses. The aryl hydrocarbon receptor (AhR) can act as a sensor for small molecules such as air pollutants and plays a crucial role in responses to (photo)pollution. On the other hand, targeting AhR/Nrf2 is emerging as a novel treatment option for air pollutants that induce or exacerbate inflammatory skin diseases. Therefore, AhR with downstream regulatory pathways would represent a crucial signaling system regulating the skin phenotype in a Yin and Yang fashion defined by the chemical nature of the activating factor and the cellular and tissue context.

Climate Change, Skin Health, and Dermatologic Disease: A Guide for the Dermatologist

Climate change has a pervasive impact on health and is of clinical relevance to every organ system. Climate change-related factors impact the skin's capacity to maintain homeostasis, leading to a variety of cutaneous diseases. Stratospheric ozone depletion has led to increased risk of melanoma and keratinocyte carcinomas due to ultraviolet radiation exposure. Atopic dermatitis, psoriasis, pemphigus, acne vulgaris, melasma, and photoaging are all associated with rising levels of air pollution. Elevated temperatures due to global warming induce disruption of the skin microbiome, thereby impacting atopic dermatitis, acne vulgaris, and psoriasis, and high temperatures are associated with exacerbation of skin disease and increased risk of heat stroke. Extreme weather events due to climate change, including floods and wildfires, are of relevance to the dermatologist as these events are implicated in cutaneous injuries, skin infections, and acute worsening of inflammatory skin disorders. The health consequences as well as the economic and social burden of climate change fall most heavily on vulnerable and marginalized populations due to structural disparities. As dermatologists, understanding the interaction of climate change and skin health is essential to appropriately manage dermatologic disease and advocate for our patients.

The impact of airborne ultrafine particulate matter on human keratinocyte stem cells

OBJECTIVE

Air pollution is today fully acknowledged to be a significant public health problem. Rapid urbanization exposed us to a variety of unhealthy ambient air pollutants at high concentrations. The emergence of airborne ultrafine particles has added an additional dimension to this already complex problem of air pollution. The skin has different functions, one of them being the protection against the deleterious effect of external agents. The aim of this study is to evaluate the impact of airborne ultrafine particles (UFP) pollution on skin aging and on keratinocyte differentiation.

METHODS

Ex vivo human skin biopsies and cultured keratinocytes stem cells (KSC) were submitted to diesel exhaust-derived UFP. Reactive oxygen species (ROS) production was assessed with the MitoSOX™ probe. Keratinocyte stemness potential was evaluated by the immunodetection of keratin 15 (K15) and p63 (∆N isoforms). Effect of UFP on the epithelial niche maintenance was evaluated by immunodetection of Sox9. Reconstructed epidermis model was used to assess the impact of UFP on keratinocyte differentiation and aging.

RESULTS

UFP exposure induced ROS production and disturbed K15, ∆Np63 and Sox9 expression in KSC or ex vivo skin. Finally, investigations on reconstructed epidermis revealed a phenotype marked by impaired keratinocyte differentiation.

CONCLUSION

These results indicate that UFP pollution is a potent extrinsic factor of skin aging, affecting the keratinocyte stem cell potential and the skin renewal process.

The differential impact of air pollutants on acute urticaria and chronic urticaria: a time series analysis

Several studies have revealed a relationship between short-term exposure to air pollution and the exacerbation of certain skin conditions. This study was developed to expand on these findings by exploring the potential association between exposure to air pollutants including particulate matter, sulfur dioxide, and ozone and the incidence of acute and chronic urticaria in Shenyang, China, from 2016 to 2018. Exposure-response relationships between daily mean concentrations of these airborne pollutants and visits to outpatient dermatological clinics for acute urticaria and chronic urticaria were evaluated via a time series analysis approach using a generalized additive model. This analysis revealed that a 10 μg/m³ increase in daily mean O₃_8h concentrations was associated with a 0.36% (95% CI, 0.31-0.41%), 0.35% (95% CI, 0.30-0.40%), and 0.34% (95% CI, 0.29-0.39%) increase in the number of outpatient visits for acute urticaria on that day (lag0), lagging day 1 (lag1), and lagging day 2 (lag2), respectively. O3 levels also had a similar but weaker effect on the frequency of patients seeking outpatient care for chronic urticaria. These analyses also revealed that estimated 0.47% (95% CI, 0.41-0.52%) and 0.46% (95% CI, 0.40-0.51%) increases in dermatological outpatient acute urticaria visits were observed for every 10μg/m3 rise in O3_8h concentrations on cumulative lagging days (lag01 and lag02). Increases in particulate matter (PM_2.5, PM₁₀) levels had a similar cumulative effect on patients with chronic urticaria. In summary, these results suggest that short-term O₃, PM_2.5, and PM₁₀ exposure can increase the risk of acute urticaria and chronic urticaria.

The association between air pollution, meteorological factors, and daily outpatient visits for urticaria in Shijiazhuang, Hebei Province, China: a time series analysis

The associations of air pollution and meteorological factors with the outpatient visits of urticaria remain poorly studied. This study aimed to assess the association between air pollution, meteorological factors, and daily outpatient visits for urticaria in Shijiazhuang, China, during 2014-2019. Daily recordings of air pollutant concentrations, meteorological data, and outpatient visits data for urticaria were collected during the 6 years. Descriptive research methods were used to describe the distribution characteristics and demographic features of urticaria. A combination of the generalized linear regression model (GLM) and distribution lag nonlinear model (DLNM) was used to evaluate the lag association between environmental factors and daily outpatient visits for urticaria. Stratified analyses by gender (male; female) and age (< 18 years; 18-39 years; > 39 years) were further conducted. The dose-response relationship between daily urticaria visits and CO, NO₂, O₃, temperature, and relative humidity was nonlinear. High concentrations of CO, NO₂, O₃, and high temperatures increased the risk of urticaria outpatient visits. The maximum cumulative association of high concentrations of CO, NO₂, and O₃ was lag 0-14 days (CO: RR = 1.10, 95%CI: 1.06, 1.31; NO₂: RR = 1.09, 95%CI: 1.01, 1.08; O₃: RR = 1.16, 95%CI: 1.08, 1.25), and high temperatures was lag 0-7 days (RR = 1.27, 95%CI: 1.14, 1.41). Low concentrations of NO₂, O₃, and high humidity, on the other hand, act as protective factors for urticaria outpatient. The maximum cumulative association of low concentrations of NO₂ was the 0-day lag (RR = 0.97, 95%CI: 0.95, 0.99), O₃ was lag 0-5 days (RR = 0.94, 95%CI: 0.88, 0.99), and high humidity was lag 0-10 days (RR = 0.93, 95%CI: 0.89, 0.98). Stratified analyses showed that the risk of urticaria outpatient visits was higher for the males and in the < 18 years age group. In conclusion, we found that the development of urticaria in Shijiazhuang has a distinct seasonal and cyclical nature. Air pollutants and meteorological factors had varying degrees of influence on the risk of urticaria outpatient visits. This study provides indirect evidence for a link between air pollution, meteorological factors, and urticaria outpatient visits.

Protective effects of a day/night dual-antioxidant serum on skin: A randomized, regimen-controlled study in Chinese women exposed to air pollution

BACKGROUND

Chronic exposure to air pollution can negatively affect skin health.

AIMS

To assess the efficacy of the LUMIVIVE^® System (LVS), a skincare system consisting of individual day and night serums, in Chinese women exposed to air pollution.

PATIENTS/METHODS

In this single-center, vehicle-controlled study, eligible females (mean age, 49.02 years) were randomized 1:1 to treatment group (LVS plus basic moisturizer) or control group (basic moisturizer). Skin color, sebum content, barrier function, elasticity, and texture were measured at baseline and at each follow-up visit (days 28, 56, and 84). Air pollution parameters were collected throughout the study.

RESULTS

Air pollution levels, including PM_2.5 and NO₂ , were consistently high during the study. The treatment group showed significantly higher skin color L* (p ≤ 0.0001) and lower a* values (p ≤ 0.05) at all follow-up visits compared with the control group, indicating lower skin pigmentation and redness, respectively. Skin color L* and a* values remained unchanged over time for the control group but were significantly different at all follow-up visits compared to baseline (p ≤ 0.0001 and p ≤ 0.05, respectively) for the treatment group. There was an increasing trend for sebum content in the control group, which was not observed in the treatment group. Both groups showed improvements over time in other skin physiology parameters.

CONCLUSIONS

The current analysis demonstrates the efficacy of LVS plus basic moisturizer compared with basic moisturizer alone to reduce skin pigmentation and redness, as well as to mitigate sebum production, in Chinese women exposed to air pollution.

Particulate matter 2.5 induces the skin barrier dysfunction and cutaneous inflammation via AhR- and T helper 17 cell-related genes in human skin tissue as identified via transcriptome analysis

Particulate matter (PM2.5) is an environmental pollutant causing skin inflammatory diseases via epidermal barrier damage. However, the mechanism and related gene expression induced by PM2.5 remains unclear. Our aim was to determine the effect of PM2.5 on human skin tissue ex vivo, and elucidate the mechanism of T helper 17 cell-related inflammatory cytokine and skin barrier function. We verified the expression levels of gene in PM2.5-treated human skin tissue using Quantseq (3' mRNA-Seq), and Gene Ontology (GO) terms and protein-protein interaction (PPI) networks were performed. The PM2.5 treatment significantly enhanced the expression of Th 1, 2, 17 and 22 cell-related genes (cut-off value: │1.2 │ > fold change and p < 0.05). Most of all, Th17 cell-related genes are upregulated and those genes are associated with skin epidermal barrier function and Aryl hydrocarbon receptor (AhR), a xenobiotic receptor, pathway. In human keratinocyte cell lines, AhR-regulated genes (e.g. AhRR, CYP1A1, IL6 and IL36G), Th17 cell-related genes (e.g. IL17C) and epidermal barrier-related genes (e.g. SPRR2A and KRT71) are significantly increased after PM2.5. In the protein level, the secretion of IL-6 and IL-36G was increased in human skin tissue following PM2.5 treatment, and the expression of SPRR2A and KRT71 was significantly increased. PM2.5 exposure could ruin the skin epidermal barrier function via AhR- and Th17 cell-related inflammatory pathway.

The relationship between short-term PM2.5 exposure and outpatient visits for acne vulgaris in Chongqing, China: a time-series study

Many researches have reported the air pollution impacts, either long term or short term, on inflammatory skin diseases, but there are few studies on the relation between PM_2.5 and acne vulgaris. To determine the correlation between short-term PM_2.5 exposure and acne outpatient visits, data for 120,842 acne vulgaris outpatient visits between December 2013 and December 2019 were obtained from three large hospitals in Chongqing, China. Both single-pollutant models and two-pollutant models were established to explore the relationship between PM_2.5 exposure and acne outpatient visits. The stratified analyses were conducted through two-sample z-tests to investigate the possible gender (male or female) and age (< 25 years or ≥ 25 years) differences in PM_2.5 effects. The results demonstrated positive correlations between PM_2.5 concentrations and acne outpatient visits. A 10 μg/m³ increase in PM_2.5 concentration was associated with a 1.71% (95% CI: 1.06-2.36%) increase in acne outpatient visits at lag 0-7 day. Stratified analyses showed that PM_2.5 effects were greater in individuals aged ≥ 25 years than those aged < 25 years, but no gender difference was found. In conclusion, short-term PM_2.5 exposure was positively associated with the risk of acne outpatient visits, especially for people ≥ 25 years old.

Research on adaption to air pollution in Chinese cities: Evidence from social media-based health sensing

Air pollution seriously threats to human health. Understanding the health effects of air pollution is of great importance for developing countermeasures. However, little is known about the real-time impacts of air pollution on the human heath in a comprehensive way in developing nations, like China. To fill this research gap, the Chinese urbanites' health were sensed from more than 210.82 million Weibo (Chinese Twitter) data in 2017. The association between air pollution and the health sensing were quantified through generalized additive models, based on which the sensitivities and adaptions to air pollution in 70 China's cities were assessed. The results documented that the Weibo data can well sense urbanites' health in real time. With the different geographical characteristics and socio-economic conditions, the Chinese residents have adaption to air pollution, indicated by the spatial heterogeneity of the sensitivities to air pollution. Cities with good air quality in South China and East China were more sensitive to air pollution, while cities with worse air quality in Northwest China and North China were less sensitive. This research provides a new perspective and methodologies for health sensing and the health effect of air pollution.

Inflammasome involvement in CS-induced damage in HaCaT keratinocytes

Cigarette smoke (CS) alters cutaneous biological processes such as redox homeostasis and inflammation response that might be involved in promoting skin inflammatory conditions. Exposure to CS has also been linked to a destabilization of the NLRP3 inflammasome in pollution target tissues such as the lung epithelium, resulting in a more vulnerable immunological response to several exogenous and endogenous stimuli related to oxidative stress. Thus, CS has an adverse effect on host defense, increasing the susceptibility to develop lung infections and pathologies. In the skin, another direct target of pollution, inflammasome disorders have been linked to an increasing number of diseases such as melanoma, psoriasis, vitiligo, atopic dermatitis, and acne, all conditions that have been connected directly or indirectly to pollution exposure. The inflammasome machinery is an important innate immune sensor in human keratinocytes. However, the role of CS in the NLRP1 and NLRP3 inflammasome in the cutaneous barrier has still not been investigated. In the present study, we were able to determine in keratinocytes exposed to CS an increased oxidative damage evaluated by 4-HNE protein adduct and carbonyl formation. Of note is that, while CS inhibited NLRP3 activation, it was able to activate NLRP1, leading to an increased secretion of the proinflammatory cytokines IL-1β and IL-18. This study highlights the importance of the inflammasome machinery in CS that more in general, in pollution, affects cutaneous tissues and the important cross-talk between different members of the NLRP inflammasome family.

The association between short-term ambient air pollution and acne vulgaris outpatient visits: a hospital-based time-series analysis in Xi'an

Recent studies have suggested that exposure to ambient airborne pollutants is associated with inflammatory skin diseases, but the epidemiological evidence regarding the association between air pollution and acne vulgaris is limited. To address that, a hospital-based time-series analysis was conducted in Xi'an, a metropolitan in northwest China. A total of 71,625 outpatient visits for acne from 2010 to 2013 were identified. The mean daily concentrations of PM10, SO2, and NO2 were 142.6 μg/m3, 44.7 μg/m3, and 48.5 μg/m3, and all were higher than WHO air quality guidelines. A generalized additive model was used to analyze the relationship between short-term ambient air pollution exposure and outpatient visits for acne. The gender- and age-specific analyses were conducted as well. The results showed that the increase of SO2 and NO2 concentrations corresponded to a significant rise in the number of outpatient visits for acne at lag 0 in both single-lag and cumulative exposure models. Both SO2 and NO2 were positively associated with acne outpatient visits for both males and females. In age-specific analyses, the effect estimate of PM10 was only significant for adults over 30 years old; SO2 was significantly associated with acne visits in children and adolescents (<21 years) and young adults (21-30 years); and NO2 was significantly associated with acne visits in all age subgroups. In conclusion, short-term exposure to ambient air pollutants (PM10, SO2, or NO2) with the average levels above WHO limits was associated with increased risk of outpatient visits for both teenage acne and adult acne. Moreover, the effects of air pollutants may vary with age.

How to prevent skin damage from air pollution part 2: Current treatment options

In the first part of this review, we have summarized the methods used to examine skin exposure to air pollution and the fundamental concept of skin-exposome interactions. Part 2 of this review focuses on dermatoses, whose aggravation or initiation by air pollution has been confirmed in evidence based medicine manner. Based on the model of photodermatology and photodermatoses, we propose a new concept of "polludermatoses." A key feature of this concept is identifying patients at risk, which will reveal the noxious effects of air pollutants on skin health. Identifying clinical signs of pollution-damaged skin could be beneficial in categorizing conditions caused or exacerbated by exposure to air pollution. Finally, we discuss the current treatment options and the pathogenetic processes targeted by these therapeutics or the development of novel treatment modalities.

Short-term effect of NO2 on outpatient visits for dermatologic diseases in Xinxiang, China: a time-series study

OBJECTIVES

As the largest organ of the human body, the skin is the major exposure route of NO₂. However, the evidence for a relationship between NO₂ exposure and dermatologic diseases (DMs) is limited. This time-series study was conducted to assess the short-term effect of nitrogen dioxide (NO₂) exposure on DMs outpatient visits in Xinxiang, China.

METHODS

Daily recordings of NO₂ concentrations, meteorological data, and the outpatient visits data for DMs were collected in Xinxiang from January 1st, 2015, to December 31st, 2018. The analysis method used was based on the generalized additive model (GAM) with quasi-Poisson regression to investigate the relationship between NO₂ exposure and DMs outpatient visits. Several covariates, such as long-term trends, seasonality, and weather conditions were controlled.

RESULTS

A total of 164,270 DMs outpatients were recorded. A 10 μg/m³ increase in NO₂ concentrations during the period was associated with a 1.86% increase in DMs outpatient visits (95% confidence intervals [Cl]: 1.06-2.66%). The effect was stronger (around 6 times) in the cool seasons than in warmer seasons and younger patients (< 15 years of age) appeared to be more vulnerable.

CONCLUSIONS

The findings of this study indicate that short-term exposure to NO₂ increases the risk of DMs in Xinxiang, China, especially in the cool seasons. Policymakers should implement more stringent air quality standards to improve air quality.

The Association Between Short-Term Air Pollution Exposure and Post-Adolescent Acne: The Evidence from a Time Series Analysis in Xi'an, China

BACKGROUND

Post-adolescent acne is a common skin disease faced by adults. However, whether air pollution (AP) serves as a risk factor for post-adolescent acne remains elusive.

AIM

To determine the relationship between short-term AP exposure (within 7 days) and outpatient visits for post-adolescent acne.

METHODS

Daily outpatient visit data for post-adolescent acne and routinely AP data between 2010 and 2013 were collected from Xi'an, China. A generalized additive regression model was used to analyze the relationship between outpatient visits for post-adolescent acne and short-term ambient AP exposure. The gender-specific analyses were conducted as well.

RESULTS

Totally, 27,190 outpatient visits for post-adolescent acne were included. The results revealed that a 10 μg/m3 increase in PM10, SO2, and NO2 at lag 0-7 day was associated with the increase of outpatient visits for post-adolescent acne at 0.84% (95% CI: 0.53%, 1.16%), 1.61% (95% CI: 0.12%, 3.10%), and 3.50% (95% CI: 1.60%, 5.40%), respectively. The significant positive associations of PM10, SO2, and NO2 were found at both single-lag models and moving average models. The gender-specific analyses showed that the effect estimates of PM10 was stronger for females than for males, while there was no observed gender difference in the effects of SO2 and NO2.

CONCLUSION

Short-term exposure to AP was associated with increased outpatient visits for post-adolescent acne, especially for females in the effects of PM10.

Inflammasome Activation in Pollution-Induced Skin Conditions

SUMMARY

Exposure to air pollutants has been now associated with detrimental effects on a variety of organs, including the heart, lungs, GI tract, and brain. However, recently it has become clear that pollutant exposure can also promote the development/exacerbation of a variety of skin conditions, including premature aging, psoriasis, acne, and atopic dermatitis. Although the molecular mechanisms by which pollutant exposure results in these cutaneous pathological manifestations, it has been noticed that an inflammatory status is a common denominator of all those skin conditions. For this reason, recently, the activation of a cytosolic multiprotein complex involved in inflammatory responses (the inflammasome) that could promote the maturation of proinflammatory cytokines interleukin-1β and interleukin-18 has been hypothesized to play a key role in pollution-induced skin damage. In this review, we summarize and propose the cutaneous inflammasome as a novel target of pollutant exposure and the eventual usage of inflammasome inhibitor as new technologies to counteract pollution-induced skin damage. Possibly, the ability to inhibit the inflammasome activation could prevent cutaneous inflammaging and ameliorate the health and appearance of the skin.

Algae as an attractive source for cosmetics to counter environmental stress

In recent times, a considerable amount of evidence has come to light regarding the effect that air pollution has on skin conditions. The human skin is the chief protection we have against environmental harm, whether biological, chemical, or physical. The stress from these environmental factors, along with internal influences, can be a cause of skin aging and enlarged pores, thinner skin, skin laxity, wrinkles, fine lines, dryness, and a more fragile dermal layer. This knowledge has led to greater demand for skin cosmetics and a requirement for natural raw ingredients with a high degree of safety and efficiency in combating skin complications. Recent developments in green technology have made the employment of naturally occurring bioactive compounds more popular, and novel extraction methods have ensured that the use of these compounds has greater compatibility with sustainable development principles. Thus, there is a demand for investigations into efficient non-harmful naturally occurring raw ingredients; compounds derived from algae could be beneficial in this area. Algae, both macroalgae and microalgae, consists of waterborne photosynthetic organisms that are potentially valuable as they have a range of bioactive compounds in their composition. Several beneficial metabolites can be obtained from algae, such as antioxidants, carotenoids, mycosporine-like amino acids (MAA), pigments, polysaccharides, and scytonemin. Various algae strains are now widely employed in skincare products for various purposes, such as a moisturizer, anti-wrinkle agent, texture-enhancing agents, or sunscreen. This research considers the environmental stresses on human skin and how they may be mitigated using cosmetics created using algae; special attention will be paid to external factors, both generally and specifically (amongst them light exposure and pollutants).

Adult skin acute stress responses to short-term environmental and internal aggression from exposome factors

Exposome factors that lead to stressed skin can be defined as any disturbance to homeostasis from environmental (meteorological factors, solar radiation, pollution or tobacco smoke) and/or internal exposure (unhealthy diet, hormonal variations, lack of sleep, psychosocial stress). The clinical and biological impact of chronic exposome effects on skin functions has been extensively reviewed, whereas there is a paucity of information on the impact of short‐term acute exposure. Acute stress, which would typically last minutes to hours (and generally no more than a week), provokes a transient but robust neuroendocrine‐immune and tissue remodelling response in the skin and can alter the skin barrier. Firstly, we provide an overview of the biological effects of various acute stressors on six key skin functions, namely the skin physical barrier, pigmentation, defences (antioxidant, immune cell‐mediated, microbial and microbiome maintenance), structure (extracellular matrix and appendages), neuroendocrine and thermoregulation functions. Secondly, we describe the biological and clinical effects on adult skin from individual exposome factors that elicit an acute stress response and their consequences in skin health maintenance. Clinical manifestations of acutely stressed skin may include dry skin that might accentuate fine lines, oily skin, sensitive skin, pruritus, erythema, pale skin, sweating, oedema and flares of inflammatory skin conditions such as acne, rosacea, atopic dermatitis, pigmentation disorders and skin superinfection such as viral reactivation. Acute stresses can also induce scalp sensitivity, telogen effluvium and worsen alopecia.

Clinical and biological impact of the exposome on the skin

The skin exposome is defined as the totality of environmental exposures over the life course that can induce or modify various skin conditions. Here, we review the impact on the skin of solar exposure, air pollution, hormones, nutrition and psychological factors. Photoageing, photocarcinogenesis and pigmentary changes are well-established consequences of chronic exposure of the skin to solar radiation. Exposure to traffic-related air pollution contributes to skin ageing. Particulate matter and nitrogen dioxide cause skin pigmentation/lentigines, while ozone causes wrinkles and has an impact on atopic eczema. Human skin is a major target of hormones, and they exhibit a wide range of biological activities on the skin. Hormones decline with advancing age influencing skin ageing. Nutrition has an impact on numerous biochemical processes, including oxidation, inflammation and glycation, which may result in clinical effects, including modification of the course of skin ageing and photoageing. Stress and lack of sleep are known to contribute to a pro-inflammatory state, which, in turn, affects the integrity of extracellular matrix proteins, in particular collagen. Hormone dysregulation, malnutrition and stress may contribute to inflammatory skin disorders, such as atopic dermatitis, psoriasis, acne and rosacea.

Molecule-Resolved Visualization of Particulate Matter on Human Skin Using Multimodal Nonlinear Optical Imaging

Precise measurement of particulate matter (PM) on skin is important for managing and preventing PM-related skin diseases. This study aims to directly visualize the deposition and penetration of PM into human skin using a multimodal nonlinear optical (MNLO) imaging system. We successfully obtained PM particle signals by merging two different sources, C–C vibrational frequency and autofluorescence, while simultaneously visualizing the anatomical features of the skin via keratin, collagen, and elastin. As a result, we found morphologically dependent PM deposition, as well as increased deposition following disruption of the skin barrier via tape-stripping. Furthermore, PM penetrated more and deeper into the skin with an increase in the number of tape-strippings, causing a significant increase in the secretion of pro-inflammatory cytokines. Our results suggest that MNLO imaging could be a useful technique for visualizing and quantifying the spatial distribution of PM in ex vivo human skin tissues.

Short-Term Exposure to Ambient Air Pollution and Increased Emergency Room Visits for Skin Diseases in Beijing, China

Skin diseases have become a global concern. This study aims to evaluate the associations between ambient air pollution and emergency room visits for skin diseases under the background of improving air quality in China. Based on 45,094 cases from a general hospital and fixed-site monitoring environmental data from 2014–2019 in Beijing, China, this study used generalized additive models with quasi-Poisson regression to estimate the exposure–health associations at lag 0–1 to lag 0–7. PM_2.5 and NO₂ exposure were associated with increased emergency room visits for total skin diseases (ICD10: L00-L99). Positive associations of PM_2.5, PM₁₀, O₃ and NO₂ with dermatitis/eczema (ICD-10: L20–30), as well as SO₂ and NO₂ with urticaria (ICD-10: L50) visits were also found. For instance, a 10 μg/m³ increase in PM_2.5 was associated with increases of 0.7% (95%CI: 0.2%, 1.2%) in total skin diseases visits at lag 0–5 and 1.1% (95%CI: 0.6%, 1.7%) in dermatitis/eczema visits at lag 0–1, respectively. For PM_2.5, PM₁₀ and CO, stronger annual associations were typically observed in the high-pollution (2014) and low-pollution (2018/2019) years. For instance, a 10 μg/m³ increase in PM_2.5 at lag 0–5 was associated with increases of 1.8% (95%CI: 1.0%, 2.6%) and 2.3% (95%CI: 0.4%, 4.3%) in total skin disease visits in 2014 and 2018, respectively. Our study emphasizes the necessity of controlling the potential health hazard of air pollutants on skin, although significant achievements in air quality control have been made in China.

Natural compounds protect the skin from airborne particulate matter by attenuating oxidative stress

Particulate matter (PM) is a common indirect indicator of air pollution and threatens public health upon prolonged exposure, leading to oxidative stress, increasing the risk of develop respiratory and cardiovascular, as well as several autoimmune diseases and cancer. Nowadays, as a first line defense against PM, skin health attracted much attention. Our review summarized the skin damage mechanism induced by PM, including damage skin barrier directly, reactive oxygen species (ROS) accumulation, autophagy, and two canonical signaling pathways. Furthermore, ROS and oxidative stress have been considered pathogenesis centers, with essential skin damage roles. Extracts from plants and natural compounds which present high antioxidant capacity could be used to treat or protect against air pollution-related skin damage. We conclude the extracts reported in recent studies with protective effects on PM-mediated skin damage. Besides, the mechanism of extracts' positive effects has been revealed partially.

The impact of air pollution on skin and related disorders: A comprehensive review

As the largest organ in the body, human skin is constantly exposed to harmful compounds existing in the surrounding environment as the first-line barrier. Studies have indicated that exposure to high concentrations of many environmental factors, such as ultraviolet (UV) radiation, outdoor air pollutants, including polycyclic aromatic hydrocarbons (PAHs), volatile organic compounds (VOCs), particulate matter (PM), heavy metals, gaseous pollutants, such as carbon monoxide (CO), nitric oxides (NO_x ), sulfur oxide (SO₂ ), ozone (O₃ ), and indoor air pollutants (solid fuels consumption), might interrupt the skin's normal barrier function. Besides, the intensity of the pollutants and the length of exposure might be a contributing factor. Air pollutants are believed to induce or exacerbate a range of skin conditions, such as aging, inflammatory diseases (atopic dermatitis, cellulitis, and psoriasis), acne, hair loss, and even skin cancers (mainly melanoma and Squamous Cell Carcinoma) through various mechanisms. The interaction between pollutants and the skin might differ based on each agent's particular characteristics. Also, damaging the skin barrier seems to be closely related to the increased production of reactive oxygen species (ROS), induction of oxidative stress, activation of aryl hydrocarbon receptor (AhR), and inflammatory cytokines. This article reviews recent studies on the correlation between air pollutants and skin diseases, along with related mechanisms.

Impact of environmental changes on Dermatology

Urbanization, pollution and the modification of natural landscapes are characteristics of modern society, where the change in human relations with the environment and the impact on biodiversity are environmental determinants that affect the health-disease relationship. The skin is an organ that has a strong interface with the environment and, therefore, the prevalence patterns of dermatoses may reflect these environmental changes. In this article, aspects related to deforestation, fires, urbanization, large-scale agriculture, extensive livestock farming, pollution and climatic changes are discussed regarding their influence on the epidemiology of skin diseases. It is important that dermatologists be aware of their social responsibility in order to promote sustainable practices in their community, in addition to identifying the impacts of environmental imbalances on different dermatoses, which is essential for the prevention and treatment of these diseases.

Air pollution and skin disorders

Air pollution is being shown to play an increasing causation role in our most common skin diseases. Acne, hyperpigmentation, atopic dermatitis, and psoriasis have been shown to be influenced by air pollution. It is important for pollution to be added as a risk factor for these skin disorders, and thus we must discuss mitigating its negative affects with patients. Air pollution is the contamination of outdoor (ambient) and indoor (household) environments by any chemical, physical, or biological agent that modifies the natural characteristics of the atmosphere. Nearly all (90%) of the world's population experience daily pollution. In 2019, air pollution was considered by the World Health Organization to be the biggest environmental health risk to humans, responsible for killing more than 7 million people prematurely every year. Preliminary studies link air pollution to COVID-19 deaths, as there were high death tolls in some of the most globally polluted areas. Air pollution affects many organ systems such as cardiovascular, pulmonary, central nervous, reproductive, and integumentary systems. In this study, we detail the current evidence linking specific skin and health disorders to air pollution.

The Skin Interactome: A Holistic "Genome-Microbiome-Exposome" Approach to Understand and Modulate Skin Health and Aging

Higher demands on skin care cosmetic products for strong performance drive intense research to understand the mechanisms of skin aging and design strategies to improve overall skin health. Today we know that our needs and influencers of skin health and skin aging change throughout our life journey due to both extrinsic factors, such as environmental factors and lifestyle factors, as well as our intrinsic factors. Furthermore, we need to consider our microflora, a collection of micro-organisms such as bacteria, viruses, and fungi, which is a living ecosystem in our gut and on our skin, that can have a major impact on our health. Here, we are viewing a holistic approach to understand the collective effect of the key influencers of skin health and skin aging both reviewing how each of them impact the skin, but more importantly to identify molecular conjunction pathways of these different factors in order to get a better understanding of the integrated “genome-microbiome-exposome” effect. For this purpose and in order to translate molecularly the impact of the key influencers of skin health and skin aging, we built a digital model based on system biology using different bioinformatics tools. This model is considering both the positive and negative impact of our genome (genes, age/gender), exposome: external (sun, pollution, climate) and lifestyle factors (sleep, stress, exercise, nutrition, skin care routine), as well as the role of our skin microbiome, and allowed us in a first application to evaluate the effect of the genome in the synthesis of collagen in the skin and the determination of a suitable target for boosting pro-collagen synthesis. In conclusion, we have, through our digital holistic approach, defined the skin interactome concept, as an advanced tool to better understand the molecular genesis of skin aging and further develop a strategy to balance the influence of the exposome and microbiome to protect, prevent, and delay the appearance of skin aging signs and preserve good skin health condition. In addition, this model will aid in identifying and optimizing skin treatment options based on external triggers, as well as helping to design optimal treatments modulating the intrinsic pathways.

Microbiome in Healthy Women Between Two Districts With Different Air Quality Index

Although the diversity and abundance of skin microbiome are mainly determined by intrinsic factors, including gender, age, anatomical site, and ethnicity, we question whether facial microbiome could be affected by long-term exposure to airborne pollution. Using 16S ribosomal RNA (rRNA) gene amplicon sequencing, we analyzed the facial bacterial microbiome of healthy and young Chinese women (25-35 years old) between two districts with different air quality indices (AQIs) in Zhejiang Province. The overall microbiome structure was obviously different between these two districts. It revealed an increase in both the abundance and diversity of facial bacterial microbiome in Hangzhou (HZ) with higher AQI compared with those in Yunhe (YH) with lower AQI. Linear discriminant analysis (LDA) and Lefse analysis identified a total of 45 genera showing significant overrepresentation in the HZ group. Furthermore, PICRUSt analysis showed that functional pathways associated with metabolism of saturated fatty acid were relatively more predominant in the HZ group, whereas those with DNA repair or mitochondrial DNA replication were more predominant in the YH group. Our present data can provide useful information for further researches on the composition and function of the skin microbiome related to air pollution factors as well as for the development of therapeutic agents targeting the microbes and their metabolites to resist damages of airborne pollutants.

A Review of Advancement on Influencing Factors of Acne: An Emphasis on Environment Characteristics

Background: Acne vulgaris is known as a commonly-seen skin disease with a considerable impact on the quality of life. At present, there have been a growing number of epidemiological, medical, demographic and sociological researches focusing on various influencing factors in the occurrence of acne. Nevertheless, the correlation between environmental factors and acne has yet to be fully investigated. Objective: To assess the impacts of individual, natural and social environmental factors on acne and to construct a framework for the potential impact of built environment on acne. Methods: A thorough review was conducted into the published social demographical, epidemiological, and environmental studies on acne through PubMed, Google Scholar and Web of Science, with reference made to the relevant literature. Results: The influencing factors in acne are classed into four major categories. The first one includes individual socio-economic and biological factors, for example, gender, age, economic level, heredity, obesity, skin type, menstrual cycle (for females), diet, smoking, cosmetics products, electronic products, sleep quality and psychological factors. The second one includes such natural environmental factors as temperature, humidity, sun exposure, air pollution and chloracne. The third one relates to social environment, including social network and social media. The last one includes built environmental factors, for example, population density, food stores, green spaces, as well as other built environment characteristics for transport. Acne can be affected negatively by family history, overweight, obesity, oily or mixed skin, irregular menstrual cycles, sugary food, greasy food, dairy products, smoking, the improper use of cosmetics, the long-term use of electronics, the poor quality of sleep, stress, high temperature, sun exposure, air pollution, mineral oils and halogenated hydrocarbons. Apart from that, there are also potential links between built environment and acne. Conclusions: It is necessary to determine the correlation between the built environment and acne based on the understanding of the impact of traditional factors (sociology of population and environment) on acne gained by multidisciplinary research teams. Moreover, more empirical studies are required to reveal the specific relationship between built environment and acne.

The impact of airborne pollution and exposure to solar ultraviolet radiation on skin: mechanistic and physiological insight

For several decades air pollution has been recognized to hit drastically the skin of human body. Air pollutants predominantly accountable for aging, oxidative damage, and inflammatory allergic reactions led to psoriasis, dermatitis, acne, and skin cancer owing to the impaired functions of DNA, proteins, and lipid biomolecules. Elevated air pollution and its detrimental effects along with variations in physiological parameters of the skin are verily the scaffold for anti-pollution assertions and could be recognized as markers. The present article encompasses the salient features of air pollution and UV radiations besides dreadful effects on human skin physiological parameters and some anti-pollution approaches.

Particulate matter pollution and hospital outpatient visits for endocrine, digestive, urological, and dermatological diseases in Nanjing, China

Clinical or pathological evidence demonstrated that air pollution could undermine other organ systems of human body besides respiratory and circulation systems. Investigations that directly relate hospital outpatient visits for endocrine (ENDO), digestive (DIGE), urological (UROL), and dermatological (DERM) diseases categories with ambient particulate matter (PM) are still lacking, particularly in heavily polluted cities. Here, we conducted a time-series analysis using 812,624, 1,111,342, 539,803, and 741,662 hospital visits for ENDO, DIGE, UROL, and DERM, respectively, in Nanjing, China from 2013 to 2019. A generalized additive model was applied to estimate the exposure-response associations. Results showed that a 10 μg/m³ increase in PM_2.5 concentration on lag 0 day was significantly associated with 0.59% (95% CI: 0.30%, 0.88%), 0.43% (0.15%, 0.70%), 0.36% (0.06%, 0.66%), and 0.65% (0.42%, 0.87%) increase for ENDO, DIGE, UROL, and DERM hospital visits, respectively. The estimated effects of PM₁₀ were slightly smaller but still statistically significant. The magnitude and significance of the associations between PM and four health outcomes were sensitive to additional adjustment for co-pollutants. Exposure-response relationships were linear for PM concentrations lower than 100 μg/m³ but the curves became nonlinear across the full range of exposures due to a flatten slope at higher concentrations. We also explored the effect modifications by season (cold or warm), age (5-18, 18-64, 65-74, or 75+ years), and sex (male or female). Results showed that the DERM-related population aged 65 years or older was more vulnerable to PM exposure, compared with the 5 to 17-year age group; the DERM-related population aged 75 years or older and 65 years or older was more vulnerable to PM_2.5 and PM₁₀ exposure, respectively, compared with the 18 to 64-year age group. Our study provided suggestive evidence that ambient PM pollution was associated with ENDO, DIGE, UROL, and DERM outpatient hospital visits in Nanjing, China.

Can Plant Phenolic Compounds Protect the Skin from Airborne Particulate Matter?

The skin is directly exposed to the polluted atmospheric environment, and skin diseases, such as atopic dermatitis and acne vulgaris, can be induced or exacerbated by airborne particulate matter (PM). PM can also promote premature skin aging with its accompanying functional and morphological changes. PM-induced skin diseases and premature skin aging are largely mediated by reactive oxygen species (ROS), and the harmful effects of PM may be ameliorated by safe and effective natural antioxidants. Experimental studies have shown that the extracts and phenolic compounds derived from many plants, such as cocoa, green tea, grape, pomegranate, and some marine algae, have antioxidant and anti-inflammatory effects on PM-exposed cells. The phenolic compounds can decrease the levels of ROS in cells and/or enhance cellular antioxidant capacity and, thereby, can attenuate PM-induced oxidative damage to nucleic acids, proteins, and lipids. They also lower the levels of cytokines, chemokines, cell adhesion molecules, prostaglandins, and matrix metalloproteinases implicated in cellular inflammatory responses to PM. Although there is still much research to be done, current studies in this field suggest that plant-derived phenolic compounds may have a protective effect on skin exposed to high levels of air pollution.

The non-homogenous distribution and aggregation of carotenoids in the stratum corneum correlates with the organization of intercellular lipids in vivo

The human stratum corneum (SC) contains an abundant amount of carotenoid antioxidants, quenching free radicals and thereby protecting the skin. For the precise measurements of the depth-dependent carotenoid concentration, confocal Raman microscopy is a suitable method. The quantitative concentration can be determined by the carotenoid-related peak intensity of a Gaussian function approached at ≈1524 cm^-1 using non-linear regression. Results show that the carotenoid concentration is higher at the superficial layers of the SC then decreases to a minimum at 20% SC depth and increases again towards the bottom of the SC. In the present work, two carotenoid penetration pathways into the SC are postulated. The first pathway is from the stratum granulosum to the bottom of the SC, while in the second pathway, the carotenoids are delivered to the skin surface by sweat and/or sebum secretion and penetrate from outside. The carotenoids are aggregated at the superficial layers, which are shown by high correlation between the aggregation states of carotenoids and the lateral organization of lipids. At the 30%-40% SC depths, the ordered and dense lipid molecules intensify the lipid-carotenoid interactions and weaken the carotenoid-carotenoid interaction and thus exhibit the disaggregation of carotenoids. At 90%-100% SC depths, the carotenoid-lipid interaction is weakened and the carotenoids have a tendency to be aggregated. Thus, the molecular structural correlation of carotenoid and SC lipid might be reserved in the intercellular space of the SC and also serves as the skeleton of the intercellular lipids.

The impact of airborne pollution on skin

Indoor and outdoor airborne pollutants modify our environment and represent a growing threat to human health worldwide. Airborne pollution effects on respiratory and cardiac health and diseases have been well established, but its impact on skin remains poorly described. Nonetheless, the skin is one of the main targets of pollutants, which reach the superficial and deeper skin layers by transcutaneous and systemic routes. In this review, we report the outcomes of basic and clinical research studies monitoring pollutant levels in human tissues including the skin and hair. We present a current understanding of the biochemical and biophysical effects of pollutants on skin metabolism, inflammatory processes and oxidative stress, with a focus on polyaromatic hydrocarbons and ground-level ozone that are widespread outdoor pollutants whose effects are mostly studied. We reviewed the literature to report the clinical effects of pollutants on skin health and skin ageing and their impact on some chronic inflammatory skin diseases. We also discuss the potential interactions of airborne pollutants with either ultraviolet radiation or human skin microbiota and their specific impact on skin health.

Air Pollution and Noncommunicable Diseases: A Review by the Forum of International Respiratory Societies' Environmental Committee, Part 2: Air Pollution and Organ Systems

Although air pollution is well known to be harmful to the lung and airways, it can also damage most other organ systems of the body. It is estimated that about 500,000 lung cancer deaths and 1.6 million COPD deaths can be attributed to air pollution, but air pollution may also account for 19% of all cardiovascular deaths and 21% of all stroke deaths. Air pollution has been linked to other malignancies, such as bladder cancer and childhood leukemia. Lung development in childhood is stymied with exposure to air pollutants, and poor lung development in children predicts lung impairment in adults. Air pollution is associated with reduced cognitive function and increased risk of dementia. Particulate matter in the air (particulate matter with an aerodynamic diameter < 2.5 μm) is associated with delayed psychomotor development and lower child intelligence. Studies link air pollution with diabetes mellitus prevalence, morbidity, and mortality. Pollution affects the immune system and is associated with allergic rhinitis, allergic sensitization, and autoimmunity. It is also associated with osteoporosis and bone fractures, conjunctivitis, dry eye disease, blepharitis, inflammatory bowel disease, increased intravascular coagulation, and decreased glomerular filtration rate. Atopic and urticarial skin disease, acne, and skin aging are linked to air pollution. Air pollution is controllable and, therefore, many of these adverse health effects can be prevented.

Ambient air pollution and the hospital outpatient visits for eczema and dermatitis in Beijing: a time-stratified case-crossover analysis

BACKGROUND

Eczema and dermatitis are a group of common skin conditions with multiple risk factors. Evidence of the effects of air pollutants on eczema and dermatitis remains limited. This study aimed to investigate the effects of short-term exposure to air pollution on eczema and dermatitis in Beijing.

METHODS

A time-stratified case-crossover design was used to assess the associations between short-term changes in air pollution and the hospital outpatient visits for eczema and dermatitis in Beijing.

RESULTS

A total of 157 595 outpatient visits for eczema and dermatitis were recorded from April 1, 2012 to April 30, 2014. All pollutants showed significant positive associations with the number of outpatient visits for eczema and dermatitis on lag 0 (the current day). Per IQR increase in PM2.5, PM10, NO2 and SO2 was associated with 3.81% (95% CI: 2.92-4.7%), 3.18% (95% CI: 2.39-3.97%), 5.43% (95% CI: 4.43-6.43%) and 5.57% (95% CI: 4.55-6.58%) increases in outpatient visits for eczema and dermatitis on lag 0. Associations of air pollutants with eczema and dermatitis outpatient visits varied with the seasons and were stronger among older people and females. Also, an association of consecutive days' high concentration pollution with increased outpatient visits was observed.

CONCLUSIONS

Exposure to air pollution increases the exacerbation of eczema and dermatitis and stronger positive associations between air pollutants and outpatient visits for eczema and dermatitis were found among the aged, females and when high concentration air pollution occurs continuously.