Rising Eczema Cases Linked to Car Exhaust Chemicals

The rates of eczema, an itchy, inflammatory skin condition that affects 31.6 million Americans, has been on the rise since the 1970’s. Now researchers believe that chemicals in our environment may be behind the rapid rise of eczema, also known as atopic dermatitis. These chemicals that spew from vehicle exhaust and are used in a variety of common, household products, could cause eczema in infancy, according to new 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 at the National Institute of Allergy and Infectious Diseases Laboratory of Clinical Immunology and Microbiology, told NBC News.

Myles and his team examined “hot spots” around the country where the number of cases of atopic dermatitis were highest and discovered an abundance of chemicals called diisocyanates and isocyanates in the air. These chemicals are commonly used to make polyurethane products such as adhesives, flexible foams, carpeting and fabrics designed to be stretchy or weather resistant.  The Centers for Disease Control and Prevention says that, for consumers, these products are unlikely to be toxic if they’ve been cured or dried appropriately by the manufacturer, although the factory workers themselves could be at risk.

For consumers, the most dangerous and likely source of these chemicals may be coming from exhaust fumes from modern vehicles. This could be what has been driving the increase in eczema rates over the past 50 years. The catalytic converters that became mandatory for all vehicles in the U.S. in 1975 eliminate many of the harmful chemicals found in gasoline but, in the process, they produce isocyanates as a byproduct.

The NIH researchers took the chemicals into their laboratory and tested their reaction on mice and bacterial cultures. The found that diisocyanates and isocyanates affect the skin’s microbiome in two ways. They force healthy, protective bacteria to stop making moisturizing oils, says NBC News, and they also activate a receptor on the skin that signals the brain to induce itch and inflammation. Their findings were published in Science Advances earlier this year.

While this new understanding behind what is driving the rise in eczema may lead to better treatments for the condition, there is little people can do to prevent exposure to these chemicals, the study authors admit. 

“So much of this is out of our control,” Myles acknowledged. “I mean, you can’t shut the highways down.” He added that perhaps some filtration systems will be able to remove diisocyanates and isocyanates from the environment, but more research is needed to determine which ones might do so effectively to reduce eczema risks.