Eczema's cause could be in the air we breathe

Rates of the itchy, inflammatory skin condition have been on the rise since the 1970s. NIH researchers found specific chemicals prevalent in eczema "hot spots."


Chemicals that spew from vehicle exhaust and are used to make a variety of common products — from spandex to memory foam mattresses — could cause eczema in infancy, according to research from the National Institutes of Health.

"We have solid data establishing that pollutants are very likely behind increasing cases of atopic dermatitis," Dr. Ian Myles, chief of the Epithelial Research Unit in the National Institute of Allergy and Infectious Diseases Laboratory of Clinical Immunology and Microbiology. (Disclosure: I participated in a clinical trial run by Myles in 2018.)

Atopic dermatitis, more commonly known as eczema, is an incredibly itchy, inflammatory skin condition that affects 31.6 million Americans. It almost always begins in the first year of life, and peaks in early childhood, according to the National Eczema Association. Allergens, such as pets, perfumes, dyes and food, can cause the condition to flare up unexpectedly, even in adults.

What causes eczema in the first place has been a mystery. Genetics play a role, but the incidence of eczema has risen two to three times in industrialized countries since the 1970s, leaving experts convinced something in the environment is behind the dramatic increase.

Myles and his team turned to eczema "hot spots" around the country — places where clinics were treating higher numbers of eczema patients — and studied toxins in the surrounding environment. They found similar chemicals called diisocyanates and isocyanates to be most prevalent.

Diiocyanates are used in the manufacturing process of many polyurethane products, such as adhesives, flexible foams, carpeting and fabrics designed to be stretchy or weather-resistant.

Other than exposures for factory workers, the Agency for Toxic Substances and Disease Registry, part of the CDC, says the chemicals are unlikely to be toxic in polyurethane products as long as those items have been cured, or dried, appropriately by the manufacturer.

But it's exhaust fumes from modern vehicles that may have been driving eczema rates for the past 50 years.

Catalytic converters work by eliminating many of the harmful chemicals found in gasoline, but in that process, they produce isocyanates as a byproduct. Catalytic converters became mandatory for all vehicles in the U.S. in 1975, coinciding with the beginning of the rise in eczema cases.

The findings were published in Science Advances in January.

Dr. Jessica Hui, a pediatric allergist and immunologist at National Jewish Health in Denver, called the research "exciting."

"I think these authors are spot on in recognizing that the incidence of allergic conditions is increasing concurrently with how different pollutants are increasing in our environment," Hui said. "We're finally understanding more about why people are getting eczema."

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