Studies have found that people who have exposure to higher levels of certain types of pollution are more likely than other people to develop symptoms of eczema.

Eczema, also known as atopic dermatitis, is an umbrella term for chronic, inflammatory skin conditions. The hallmark of these conditions is dry, itchy skin. Since the 1970s, the incidence of eczema has increased up to three-fold in industrialized countries, making it one of the most common skin conditions in the United States.

The rise in eczema cases has been most pronounced in urban areas — to the point where some experts consider eczema an epidemic in urban populations.

A variety of lifestyle and environmental factors, including exposure to air pollution, may contribute to a high prevalence of eczema in urban populations. Studies in both children and adults have linked exposure to higher levels of certain types of pollution with an increased likelihood of developing symptoms of eczema.

In this article, experts Dr. Elizabeth Matsui and Dr. John Balmes discuss how pollution affects eczema and what this means for overall health and wellness.

Pollution can trigger inflammation in people with eczema.

Dr. Matsui is an associate chair for research in the Department of Population Health and a professor of population health and pediatrics at the University of Texas at Austin.

“Inflammation is [discoloration], swelling, and tenderness that is caused by substances that are released by the immune system,” Dr. Matsui explained.

“Eczematous skin is susceptible to [pollution] because the skin barrier — formed by cells that line the surface of the skin — is disrupted,” she elaborated. “That means that the ‘mortar’ that fills in the cracks in between the cells is broken down.”

“This allows substances in the environment, such as air pollution, to penetrate below the surface of the skin, where it can interact with immune cells.”

Dr. Balmes, a professor of environmental health sciences at the University of California in Berkeley, explained that air pollution contains reactive oxygen species that can injure the skin and result in inflammation. Inflammation causes more damage to the skin, leading to both the development and worsening of eczema symptoms.

Research has linked many types of pollutants to eczema, including:

  • fine particulate matter, which refers to particles ≤ 2.5 microns in diameter, also known as PM2.5
  • ozone
  • nitrogen dioxide
  • carbon monoxide
  • lead
  • sulfur dioxide and sulfate

These are the types of pollutants that are commonly present in large urban areas. Power plants, automobiles, construction sites, and industrial furnaces all release them into the environment.

Dr. Balmes was involved in a recent study that also found that exposure to air pollution from wildfires — which contains high concentrations of fine particulate matter — increased the likelihood of children requiring medical care for their eczema symptoms by 45%.

“There is no question that air pollution can exacerbate asthma,” said Dr. Balmes.

This is especially important for people with eczema to keep in mind. Studies suggest that more than 1 in 4 people with eczema also have asthma.

“Air pollution causes inflammation of the lungs, can lead to the development of asthma, and can trigger symptoms in people who have asthma,” Dr. Matsui explained.

Dr. Balmes added that air pollution likely also affects psoriasis, another inflammatory skin condition that people sometimes mistake for eczema.

“This is an area that is not well-understood,” Dr. Matsui explained. “However, we do know that Communities of Color experience higher air pollution exposure, and these same communities have a disproportionate burden of eczema.”

According to the American Lung Association, as of 2021, approximately 70 million people in historically marginalized groups live in areas with high levels of ozone and particulate pollution in the U.S. This may partly explain why Black and Hispanic children tend to have more severe eczema than white children in the U.S.

“Air pollution could be responsible for some of the racial and ethnic disparities in eczema, but that has not been directly studied,” Dr. Matsui clarified.

Dr. Balmes added that individuals whose work requires them to spend large amounts of time outside — such as agricultural or construction workers — have higher exposure to air pollution. Data from the Bureau of Labor Statistics suggest that Hispanic or Latinx individuals represent 25­–33% of people working in these kinds of fields.

To help keep eczema under control, Dr. Matsui recommended moisturizing regularly using creams or moisturizers with a thick consistency rather than lotions. Bathing daily is also important.

She also noted that it is important for people to use any medications that their dermatologist has prescribed to help control symptoms.

Dr. Balmes recommended wearing long-sleeved shirts and pants to protect the skin but acknowledged that this can be difficult during warm weather.

If possible, people should try to limit the time they spend outdoors when the Air Quality Index (AQI) is high. The AQI value is a measure of the levels of five major pollutants in the air, including those that are known triggers of eczema symptoms.

There is a high prevalence of eczema in urban areas with high levels of pollution. This is likely because pollution can trigger inflammation in eczema-prone skin.

“With climate change, there will be more wildfires as well as more ozone, so likely greater pollutant exposures to people with eczema,” Dr. Balmes noted.

“If we understood the connections between air pollution, eczema, and racial and ethnic disparities in eczema better, we would be in a much better position to intervene to reduce the burden of eczema among ethnic minority populations,” Dr. Matsui concluded.

Although it is clear that pollution and eczema have a connection, more work is necessary before researchers can fully understand the implications of this relationship.