How Does Air Pollution Affect Eczema?

Over the last half a century, the prevalence of eczema has dramatically increased around the world, especially in wealthier and developed regions.^[1] Although the exact reason for this increase is unclear, many researchers believe that exposure to certain chemicals in the environment may have something to do with it.^[2] Air pollutants are chemicals from both indoor and outdoor environments that may bind and penetrate the skin.  From there it can possibly reach the deeper skin and enter the bloodstream to negatively affect our health.^[3] A large part of eczema treatment revolves around reducing one’s exposure to harmful environmental triggers that may flare eczema, especially in early life. The role that several airborne pollutants may play in the development of eczema has been studied.

Tobacco Smoke 

Although tobacco smoke exposure is strongly linked to a higher risk of childhood asthma, its role in eczema is less clear.^[4] Overall, it appears that people with eczema tend to have more tobacco exposure. In a meta-analysis of 86 studies spanning 39 countries, researchers found that childhood eczema is strongly linked to smoking exposure (including second-hand smoke), but not when the mother smokes during pregnancy.^[5]

Indoor Pollution

There are many sources of indoor pollution, such as chemicals in paints, flooring, cleaning solutions, air conditioning and heating, and burning stoves.^[3] Interestingly, indoor home remodeling activities, such as changing home floor covering, wallpaper, and repainting of walls are associated with acute worsening of childhood eczema.^[6] Also, moving to a newly built home before a child turns one-year-old is a risk factor for developing eczema in elementary and middle school-aged children.^[7] Furthermore, children who live in houses (and especially bedrooms) that have lower air ventilation are more likely to develop eczema.^[8]

Outdoor Pollution

The main outdoor pollutant chemicals are carbon monoxide, nitrogen dioxide, and sulfur dioxide.^[3] They can come from many sources including dust, volcanoes, and forest fires, as well as industrial and mechanical wastes from automobiles, factories, and power plants. Researchers in Taiwan have found that traffic pollution can significantly increase the risk of eczema.^[9] In Korea, school-aged children tend to report more intense itching when outdoor air pollution levels are high.^[10,11] In Germany, the rate of childhood eczema is higher in those who live within 50 meters of main roads with heavy traffic.^[12] Researchers theorize that the higher level of toxic pollutants from automobiles in the main roads may play a role in eczema.^[12]

How Do Air Pollutants Really Affect the Skin in People with Eczema?

Researchers believe these risks may be caused by high levels of volatile organic compounds (VOCs) in the air pollutants when those come in contact with the skin.^[7] Exposure to these chemicals can trigger skin inflammation and cause damage to the skin’s natural protective barrier, causing more water to evaporate from the skin, which causes dry skin and ultimately worsens eczema.^[13,14]

Is Living in Suburban and Rural Environments Better for Eczema?

One may think that people living in urban areas are exposed to more air pollution, and therefore are more likely to get eczema than those living in suburban and rural areas. However, this is not entirely clear: although some researchers have shown that urban living is associated with a higher risk for eczema, others have found the opposite association or no association.^[15] In other words, the jury is still out on whether urban living is bad for eczema.