How Does Air Pollution Affect Eczema?
Pollution can affect skin health
Over the last half a century, the prevalence of eczema has dramatically increased around the world, especially in wealthier and developed regions. 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. 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. 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.
Although tobacco smoke exposure is strongly linked to a higher risk of childhood asthma, its role in eczema is less clear. 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.
There are many sources of indoor pollution, such as chemicals in paints, flooring, cleaning solutions, air conditioning and heating, and burning stoves. Interestingly, indoor home remodeling activities, such as changing home floor covering, wallpaper, and repainting of walls are associated with acute worsening of childhood eczema. 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. Furthermore, children who live in houses (and especially bedrooms) that have lower air ventilation are more likely to develop eczema.
The main outdoor pollutant chemicals are carbon monoxide, nitrogen dioxide, and sulfur dioxide. 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. 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. Researchers theorize that the higher level of toxic pollutants from automobiles in the main roads may play a role in eczema.
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. 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. In other words, the jury is still out on whether urban living is bad for eczema.
- Deckers IA, McLean S, Linssen S, et al. Investigating international time trends in the incidence and prevalence of atopic eczema 1990-2010: a systematic review of epidemiological studies. PLoS One.2012;7(7):e39803; https://pubmed.ncbi.nlm.nih.gov/22808063/.
- Cork MJ, Robinson DA, Vasilopoulos Y, et al. New perspectives on epidermal barrier dysfunction in atopic dermatitis: gene-environment interactions. J Allergy Clin Immunol.2006;118(1):3-21; quiz 22-23; https://pubmed.ncbi.nlm.nih.gov/16815133/.
- Ahn K. The role of air pollutants in atopic dermatitis. J Allergy Clin Immunol.2014;134(5):993-999; discussion 1000; https://pubmed.ncbi.nlm.nih.gov/25439225/.
- Burke H, Leonardi-Bee J, Hashim A, et al. Prenatal and passive smoke exposure and incidence of asthma and wheeze: systematic review and meta-analysis. Pediatrics.2012;129(4):735-744; https://pubmed.ncbi.nlm.nih.gov/22430451/.
- Kantor R KA, Thyssen J, et al. Association of atopic dermatitis, Acad wsasram-aJA, Dermatol. PMID. https://pubmed.ncbi.nlm.nih.gov/27542586/
- Lee JH, Suh J, Kim EH, et al. Surveillance of home environment in children with atopic dermatitis: a questionnaire survey. Asia Pac Allergy.2012;2(1):59-66; https://pubmed.ncbi.nlm.nih.gov/22348208/
- Lee JY, Seo JH, Kwon JW, et al. Exposure to gene-environment interactions before 1 year of age may favor the development of atopic dermatitis. Int Arch Allergy Immunol.2012;157(4):363-371; https://pubmed.ncbi.nlm.nih.gov/22123373/.
- Bornehag CG, Sundell J, Hagerhed-Engman L, et al. Association between ventilation rates in 390 Swedish homes and allergic symptoms in children. Indoor Air.2005;15(4):275-280; https://pubmed.ncbi.nlm.nih.gov/15982274/.
- Lee YL, Su HJ, Sheu HM, et al. Traffic-related air pollution, climate, and prevalence of eczema in Taiwanese school children. J Invest Dermatol.2008;128(10):2412-2420; https://pubmed.ncbi.nlm.nih.gov/18449213/.
- Song S, Lee K, Lee YM, et al. Acute health effects of urban fine and ultrafine particles on children with atopic dermatitis. Environ Res.2011;111(3):394-399; https://pubmed.ncbi.nlm.nih.gov/21367405/
- Kim J, Kim EH, Oh I, et al. Symptoms of atopic dermatitis are influenced by outdoor air pollution. J Allergy Clin Immunol.2013;132(2):495-498 e491; https://pubmed.ncbi.nlm.nih.gov/23763977/
- Morgenstern V, Zutavern A, Cyrys J, et al. Atopic diseases, allergic sensitization, and exposure to traffic-related air pollution in children. Am J Respir Crit Care Med.2008;177(12):1331-1337;https://pubmed.ncbi.nlm.nih.gov/18337595/.
- Eberlein-Konig B, Przybilla B, Kuhnl P, et al. Influence of airborne nitrogen dioxide or formaldehyde on parameters of skin function and cellular activation in patients with atopic eczema and control subjects. J Allergy Clin Immunol.1998;101(1 Pt 1):141-143; https://pubmed.ncbi.nlm.nih.gov/9449520/.
- Huss-Marp J, Eberlein-Konig B, Breuer K, et al. Influence of short-term exposure to airborne Der p 1 and volatile organic compounds on skin barrier function and dermal blood flow in patients with atopic eczema and healthy individuals. Clin Exp Allergy.2006;36(3):338-345; https://pubmed.ncbi.nlm.nih.gov/16499645/.
- Schram ME, Tedja AM, Spijker R, et al. Is there a rural/urban gradient in the prevalence of eczema? A systematic review. Br J Dermatol.2010;162(5):964-973; https://pubmed.ncbi.nlm.nih.gov/20331459/