Fine Particulate Air Pollution Tied to Higher Atopic Dermatitis Risk

People who live in areas with higher levels of fine particle air pollution face about twice the risk of developing atopic dermatitis (eczema), compared with those in areas with cleaner air, according to a new study that provides the most comprehensive look yet at this relationship in the United States.

The research, led by Gloria F. Chen of Yale School of Medicine and published in PLOS ONE, analyzed data from more than 286,000 adults across 788 locations nationwide, finding that those diagnosed with eczema lived in areas with significantly higher concentrations of fine particulate matter, or PM_2.5, which refers to airborne particles smaller than 2.5 micrometers in diameter.

“The odds of eczema increased with greater PM_2.5 concentration in this large, diverse, adult American cohort,” the study authors wrote. “Ambient air pollution is an environmental hazard that influences inflammatory skin disease, suggesting possible targeted interventions.”

Previous research on the relationship between air pollution and atopic dermatitis showed mixed results. A 2016 national survey of children found that higher annual PM_2.5 levels were actually linked to lower eczema rates overall, but more severe symptoms during cold months. A 2023 study in North Carolina showed PM_2.5was associated with more eczema cases, but only when combined with other pollutants. And following the 2018 California Camp Fire, dermatology clinics saw more eczema visits, particularly among older adults.

This new study used medical records from the National Institutes of Health's All of Us Research Program, which includes participants from traditionally underrepresented groups. The researchers matched participants' locations with air quality data and found that for every 10-unit increase in PM_2.5 concentration, the odds of having eczema approximately doubled.

The connection remained strong even after accounting for factors such as age, sex, race, income, smoking status and other allergic conditions. Similar results have also been reported from Taiwan, Germany and Australia, which all showed about twice the eczema risk with each 10-unit increase in PM_2.5.

The study found that eczema can worsen when air quality drops from "good" to "moderate" levels on the Environmental Protection Agency’s Air Quality Index, with higher pollution bringing greater risks. People with atopic dermatitis may want to stay indoors, use air filters or cover exposed skin if going outdoors when air quality hits moderate or worse levels, the study authors said.