Air Pollution and Atopic Dermatitis, from Molecular Mechanisms to Population-Level Evidence: A Review

Abstract

Atopic dermatitis (AD) has increased in prevalence to become the most common inflammatory skin condition globally, and geographic variation and migration studies suggest an important role for environmental triggers. Air pollution, especially due to industrialization and wildfires, may contribute to the development and exacerbation of AD. We provide a comprehensive, multidisciplinary review of existing molecular and epidemiologic studies on the associations of air pollutants and AD symptoms, prevalence, incidence, severity, and clinic visits. Cell and animal studies demonstrated that air pollutants contribute to AD symptoms and disease by activating the aryl hydrocarbon receptor pathway, promoting oxidative stress, initiating a proinflammatory response, and disrupting the skin barrier function. Epidemiologic studies overall report that air pollution is associated with AD among both children and adults, though the results are not consistent among cross-sectional studies. Studies on healthcare use for AD found positive correlations between medical visits for AD and air pollutants. As the air quality worsens in many areas globally, it is important to recognize how this can increase the risk for AD, to be aware of the increased demand for AD-related medical care, and to understand how to counsel patients regarding their skin health. Further research is needed to develop treatments that prevent or mitigate air pollution-related AD symptoms.

Air pollution and global healthcare use for atopic dermatitis: A systematic review

“…However, most longitudinal studies, which employ a stronger study design, have reported positive associations for both children and adults 11,15,58,59 . Regarding molecular mechanisms, air pollutants may contribute to AD symptoms by disrupting skin barrier function, activating the aryl hydrocarbon receptor pathway, promoting oxidative stress and initiating a pro‐inflammatory response 60,61,62 . Further research is needed on the synergistic effects of combined air pollutants on AD incidence and severity, at both molecular and population levels.…”

The Efficacy and Effectiveness of the Biological Treatment of Pruritus in the Course of Atopic Dermatitis

“…In addition, a number of environmental factors have been implicated in the global increase in AD, i.e., air pollution, tobacco smoke, aeroallergens, infectious pathogens, antibiotics, poor lifestyle and diet, and increasing obesity rate, as well as changes in the gut and skin microbiome, and these may act through alterations in the expression of genes [ 12 , 15 ]. Air pollution has been found to provoke AD and the occurrence of flares in in vivo and in vitro tests and in various long-term epidemiological studies [ 16 ]. There is evidence suggesting that in the case of elderly-onset AD, lifetime exposure to air pollutants may be more significant than genetic predisposition [ 17 ].…”

Impact of climate change on atopic dermatitis: A review by the International Eczema Council

“…28 The mechanisms underlying the effects of wildfire smoke on the skin include oxidative stress, inflammation, disruption of skin barrier function, and aryl hydrocarbon receptor signaling and dysbiosis. 29,30 Wildfires produce significant amounts of air pollution, with 90% of total inhalable particle mass comprised of PM 2.5 (PMs 2.5 μm in diameter or smaller). Tracking and monitoring PM 2.5 is used to estimate public health effects from wildfire smoke, including on the skin.…”