Childhood Eczema: An Environmental Scan
Table of Contents
3.2.4 Environmental Factors
Much attention has focused on the environment and its association to eczema. In particular, factors and patterns of the environment from both the outdoor environment and the indoor microclimate have shed light on how the environment impacts individuals with eczema. Within the home, humidity levels and the level of ventilation can worsen eczema conditions. McNally and associates reported a statistically significant association between eczema in children and increased humidity in the home and excessive heat and dryness specifically in the child’s bedroom (31).
Not only are air quality issues a concern in the fight against eczema but a whole host of chemicals and toxins throughout the environment, both known and unknown are believed to play a role in the development of eczema and exacerbation of symptoms. For example, in July, 2008 the Eczema Natural Treatment website posted an information piece describing the use of dimethyl fumarate in furniture production (used to prevent mold). This highly sensitive agent is known to cause serious harm among individuals who are exposed thus, the use of dimethyl furmarate in manufacturing poses a serious risk at large and specifically for individuals who already have eczema. This is only one example of the numerous chemicals found in our everyday environments that not only affect overall health but may be particularly devastating to individuals with certain sensitizations.
Concerning the outdoor environment, for example actual weather patterns, can affect people suffering with eczema. Various seasons can impact eczema such as the cold in winter causing skin to become drier and increasingly itchy whereas, warmer temperatures and sunny conditions have promoted the remission of eczema for many. However, in very humid and hot environments sweat can increase suffering. An increase in symptoms of eczema in the spring and summer climates is likely an indication of seasonal allergies where reactions to pollen are influencing symptoms. See Appendix G: ‘Environmental Triggers’ for a list of more common environmental triggers of eczema. In Germany, researchers specifically examined the influence of daily temperatures, humidity, radiation and pollen levels in the air. Their findings showed seasonal variations are very different among children and no one pattern is applicable to all. Some children showed worse symptoms as the air temperature dropped and others were highly influenced by pollen, which made their itch symptoms much worse. Overall, the results of the study highlighted the need to more fully examine not only seasonal variations of symptoms among children with eczema but also include detailed work surrounding the relationship among climate factors and specific types of eczema to better understand the impact of different seasons (32).
There are sparse epidemiologic studies that specifically examine air pollution (outside) and climatic factors and their association with eczema. The ISSAC programme has shown an increased likelihood between air pollution and the prevalence of eczema in children (33). Similarly, very recent work completed in Taiwan supports the hypothesis that air pollution and climatic factors may impact the development and severity of eczema. Lee and associates looked at data from air monitoring stations and the prevalence of eczema among 300,000 plus school age children. Results showed eczema was associated with air pollution from traffic (the nitrogen oxides and carbon monoxide). Additionally, the relative humidity levels were also associated with eczema. Overall, their work does show an association between air pollution elements and climatic factors with respect to eczema (34).Clinicians and individuals with eczema are well aware of how eczema flare-ups and symptoms are influenced by particular seasons; however, there is little scientific research that has investigated how specifically this happens.
Another aspect of the environment under investigation is the Urban versus Rural question. Research out of New Zealand, Greece and Germany has all focused on possible exposure characteristics between living in a rural versus urban population and the development of eczema in children. As may be expected, long term exposure in the urban environment is associated with hayfever (35) and air pollution as discussed above. Conversely, there was a protective affect found when examining the prevalence of eczema in those children who had long term exposures in the rural environment where they were found to develop eczema less often.
Over 1,300 children born to mothers who lived on a farm during their pregnancy had a 50% lower risk of developing eczema and hayfever along with a reduction in asthma. Results of this study render further support for the hygienic hypothesis (see Section 3.2.2) by suggesting that children who are exposed to bacteria and animals may have their immune system challenged at the fetal stage of life; however, the protective effect may only continue if the child continues exposure after birth (36). Conversely, work out of Germany has shown there is a link between the development of child allergies and environmental pollution. Allergies such as eczema, hayfever and asthma were 50% higher in children who resided near major roads. Various factors such as climatic zones, altitude, humidity levels, pollutions levels, ground level ozone and outdoor pollen are areas where researchers are interested in continuing their investigations to uncover factors associated with the symptomology of eczema among all age groups (37).