Air Pollution Linked to Worse Atopic Dermatitis

With new data showing a stronger potential connection between atopic dermatitis (AD) and increased levels of environmental pollutants, the population burden of this chronic inflammatory skin condition that is also considered an immune-mediated disease remains significant—with potential to continue to grow.

If measures to mitigate how pollution and climate change do not improve, neither may patient outcomes, according to a new meta-analysis published in JAMA Dermatology.1 Using MEDLINE, EMBASE, and Cochrane databases, a team of investigators searched for research on correlations between AD outcomes and environmental factors—ambient air pollution, weather, and climate—from inception to June 28, 2024. These cohort, case-control, cross-sectional observations studies were of adult patients 18 years and older; ultimately, 42 studies from 14 countries and 1985 to 2024 were included, with certainty of evidence assessed using Grading of Recommendations Assessment, Development, and Evaluation.

After reviewing their findings, the authors saw an uptick in AD outpatient clinical visits per 4 ambient environmental pollutants, using 10-μg/m3 increases as measures:

• Particulate matter 10 μm in diameter or smaller (risk ratio [RR], 1.008; 95% CI, 1.003-1.012; high-certainty evidence)
• Particulate matter 2.5 μm in diameter or smaller (RR, 1.013; 95% CI, 0.999-1.027; moderate-certainty evidence)
• Sulfur dioxide (RR, 1.029; 95% CI, 1.020-1.039; high-certainty evidence)
• Nitrogen dioxide (RR, 1.014; 95%CI, 0.999-1.030; moderate-certainty evidence)

The population burden of atopic dermatitis, a chronic inflammatory skin condition that is also considered an immune-mediated disease remains significant; if measures to mitigate how pollution and climate change do not improve, neither may patient outcomes. | Image Credit: Maggie Shaw-sora.chatgpt.com

“To our knowledge, research on the association of environmental factors and atopic dermatitis has not been comprehensively synthesized alongside an assessment of the certainty of evidence,” the authors wrote. They also highlighted that these associations remain uncertain, with some studies reporting links between AD and particulate matter and harmful gas increases but others reporting no associations or that cold weather worsens the AD burden.2-6

The authors also saw a rise in emergency department (ED) visits. For every 10-μg/m3 increase in particulate matter 10 μm in diameter or smaller, there was a 1% increase in ED or clinical visits (RR, 1.008; 95% CI, 1.003-1.012; high-certainty evidence), and for every 10-μg/m3 increase in particulate matter 2.5 μm in diameter or smaller, there was “probably an increase” in ED or clinical visits (RR, 1.013; 95% CI, 0.999-1.027; moderate-certainty evidence).

Looking at adulthood specifically, there is likely no association between exposure to nitric oxide or nitrogen dioxide and AD in adulthood; no studies included in this meta-analysis showed increases in medical visits at elevated levels.

Also, accounting for temperature, 10 studies demonstrated correlations between higher temperatures in hot climates or seasons and more AD-related ED or clinical visits. This association was more likely to be seen in female individuals compared with male individuals, but for outpatient visits. Six studies also reported links between lower temperatures in cold climates and seasons and more daily AD-related ED or clinical visits.

Precipitation and sunlight were examined as well, and although the evidence was deemed low certainty, the authors saw potential connections each between high amounts of precipitation and humidity and greater AD severity.

Probable associations were seen, too, between the following and greater AD prevalence: environmental tobacco smoke and traffic-related air pollution, secondhand smoke, and traffic and industrial plants exposure.

Overall, the associations they saw indicated harmful correlations between population-level AD activity and various ambient air pollutants. These findings are strong, the authors explained, because their review synthesized evidence on broad factors and the results were generally consistent with previous reviews, including recent studies.

“These findings have direct public health implications, adding to the impetus to decrease pollution and mitigate climate change worldwide,” they concluded.

References

1. Park M, Mohsen ST, Katz T, et al. Climate conditions, weather changes, and air pollutants and atopic dermatitis: a meta-analysis. JAMA Dermatol. Published online June 25, 2025. doi:10.1001/jamadermatol.2025.1790
2. SchnassW, Hüls A, Vierk.tter A, Kr.mer U, Krutmann J, Schikowski T. Traffic-related air pollution and eczema in the elderly: findings from the SALIA cohort. Int J Hyg Environ Health. 2018;221(6):861-867. doi:10.1016/j.ijheh.2018.06.002
3. Tang KT, Ku KC, Chen DY, Lin CH, Tsuang BJ, Chen YH. Adult atopic dermatitis and exposure to air pollutants-a nationwide population-based study. Ann Allergy Asthma Immunol. 2017;118(3):351-355. doi:10.1016/j.anai.2016.12.005
4. Park SK, Kim JS, Seo HM. Exposure to air pollution and incidence of atopic dermatitis in the general population: a national population-based retrospective cohort study. J Am Acad Dermatol. 2022;87(6):1321-1327. doi:10.1016/j.jaad.2021.05.061
5. Sargen MR, Hoffstad O, Margolis DJ.Warm, humid, and high sun exposure climates are associated with poorly controlled eczema: PEER (Pediatric Eczema Elective Registry) cohort, 2004-2012. J Invest Dermatol. 2014;134(1):51-57. doi:10.1038/jid.2013.27416
6. Vocks E, Busch R, Fr.hlich C, Borelli S, Mayer H, Ring J. Influence of weather and climate on subjective symptom intensity in atopic eczema. Int J Biometeorol. 2001;45(1):27-33. doi:10.1007/s004840000077