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Annie Foley
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Particles in bad air trigger eczema and increase clinic visits, new study shows
Image by sruik/cgdeaw/canva
Air pollution is often blamed for asthma, strokes, heart failure and other common diseases you might imagine it could exacerbate. Your skin suffers, too, new research reveals.
Tiny particles of pollution in the air, from car exhaust, wildfires, or even plowed farm fields, donโt just hang invisibly around us. When concentrations rise, so do clinic and urgent care visits for people with atopic dermatitis, a common form of eczema. And the higher the particle levels, the greater the number of visits.
Thatโs worrisome given how common eczema is, affecting nearly one in five children and one in ten US adults. Worldwide, about 223 million people (which is roughly the population of Brazil), have eczema. If youโre one of them, your skin may be more vulnerable to whatโs in the air than you realize. That susceptibility can cause more than itchy skin, it can lead to lost sleep, missed work, and a daily fight to feel comfortable.
Another concern is that air pollution isnโt going away. Despite decades of cleaning up air pollution, more than 131 million Americans still live in places with failing grades for particle pollution. Phoenix, Houston, and Los Angeles have flunked air quality tests for decades. In fact, 11.7 million more people were exposed to harmful air this year compared to last year, according to the State of the Air report from the American Lung Association.
How dirty air damages skin
Pollutants break down the skinโs protective barrier, which results in water loss, causing dry, irritated skin. With a weakened barrier, the skin is also more vulnerable to outside irritants, which can activate inflammatory pathways. Since airborne particulate matterโโโspecks about the width of a cotton fiberโโโcan penetrate the skin, free radicals are created that damage collagen and elastin, two important skin-building blocks, leading to sagging and aging skin.
People with inflammatory conditions, such as eczema or sensitive skin are most at risk.
Weather also plays a role in skin health. Dry, low-humidity air can parch the skin, making it more susceptible to inflammation. High humidity makes sweat linger on the skin, clogging pores and trapping irritants. This buildup can also spark inflammation and often leads to flare-ups of acne or eczema.
Examining the global problem
To understand how environmental factors affect eczema, scientists pulled together 42 studies from 14 countries, involving over 20 million adults. They looked at:
- Airborne particles (large and small)
- Pollutant gases (nitrogen dioxide, sulfur dioxide, ozone, carbon monoxide)
- Weather factors: (temperature, humidity, and sunlight)
They measured three outcomes: healthcare and emergency room (ER) visits, the number of people who had or developed eczema, and how severe the symptoms were.
Pollution as a flare accelerator
An increase in office and urgent care visits was caused by the following:
1) Particulate matter
Every 10 microgram increase of small and large pollutant particles floating in one cubic meter of air, increased the relative risk of an atopic dermatitis outpatient or ER visit by 1.3% and 0.8% respectively. (A 10 microgram increase is equal to a 7% rise above the EPAโs daily safety threshold for large particles.)
That might sound like a small change, but for a city with 100,000 eczema-related visits a year, it means an extra 800 and 1,300 visits annually. Multiply that across millions of people, and the public health burden and strain on clinics becomes real.
In Chengdu, China, a 10 microgram increase of large particles in one cubic meter of air resulted in more than 1,000 additional visits per year. In Beijing, increases in small and large particulates led to a 3% to 6% spike in visits, translating to thousands of extra cases.
2) Sulfur dioxide
-Every 10 microgram increase in a cubic meter of air of sulfur dioxide increased the relative risk of an atopic dermatitis outpatient or ER visit by 1.029%, the strongest association. The other pollutants, nitrogen dioxide, carbon monoxide and ozone had little or no effect.
3) Temperature extremes
-Both high and low temperatures caused more atopic dermatitis-related visits
In Chengdu, China, temperatures below 19.6 ยฐCelsius (67 ยฐFahrenheit) or above 25.3 ยฐC (78 ยฐF) resulted in an increased relative risk of visits, and visits nearly doubled when temperatures dropped below 0 ยฐC (32 ยฐF).
Interestingly, the other two measured outcomes, the prevalence or severity of eczema didnโt change much with pollution or weather changes. Researchers think this is because pollution and weather changes act as triggers for short-term spikesโโโenough to send people to the doctor increasing office visits, but not necessarily enough to shift long-term disease rates. In short, pollution and weather extremes, act as a flare accelerator, not a root cause.
Past studies back up findings
Other studies tell a similar story.
Children exposed to wildfire pollution, like the Canadian wildfires, are 45% more likely to need medical care for their eczema, according to a study published in JAMA Network.
Children growing up in urban, polluted areas are also more likely to develop eczema, especially compared to those in rural settings, even when controlling for diet and genetics. Eczema prevalence is 6% in children from Chinaโs urban regions compared to 4% in the country.
A Korean study of greater than 10,000 patients found ER visits spiked during both freezing days and heat waves. A daily temperature swing of 14 ยฐC was associated with an increase in atopic dermatitis symptoms, and when it swung by 19 ยฐC, the severity of symptoms quadrupled.
What you can do to protect your skin
Other than moving to Finland, which consistently ranks as one of the countries with the best air quality, there are simple changes you can make to help your skin.
Cleanse thoroughly.
Wash your skin twice daily with a gentle water-based cleanser to remove particulate matter, dirt, toxins, and impurities. Micellar water is helpful for those with sensitive skin to avoid over-stripping the skin barrier. An oil-based cleanser may be needed to remove water-resistant sunscreens and makeup.
Load up on antioxidants.
Apply products rich in Vitamin C, Vitamin E, or Ferulic Acid to neutralize free radicals. Niacinamide is another powerful antioxidant that strengthens the skin barrier, reduces inflammation, and helps control acne to boot.
Donโt skip sunscreen.
Since UV radiation amplifies the negative effects of air pollution on the skin, use a broad-spectrum sunscreen with SPF 30 or higher. Sunscreens that contain titanium dioxide or zinc oxide also provide a physical barrier against pollution. Reapply sunscreen every two hours if youโre outdoors or exposed to smog.
Boost your skin barrier.
Since pollution weakens the skinโs protective barrier, moisturizers with ceramides, hyaluronic acid, and glycerin, which hydrate and reinforce the skin barrier, are excellent choices. Ingredients like shea butter or dimethicone also help seal in moisture and form a protective coating on the skinโs surface.
Check the daily air quality index (AQI). An air quality Index value of 151 or above is in the red zone and is considered unhealthy. It may be best to stay indoors as much as possible during red days. If you must go outside, avoid strenuous activities.
Air pollution and heat waves may seem like distant climate issues, but their negative effects can show up on your skin. Consider indoor pollution, too. The air inside, where the average persons spends nearly 90% of life, can be just as irritating, packed with chemicals and particles that inflame sensitive skin, studies show. Keeping an eye on the air quality, both indoor and outdoor, is one more way to protect your skin.
The Hidden Skin Cost of Dirty Air was originally published in Wise & Well on Medium, where people are continuing the conversation by highlighting and responding to this story.
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