Can The Climate Crisis Affect Eczema?

As the climate crisis escalates, the ongoing question emerges: how will it affect human health? It is likely that it will affect infectious disease transmission, heat-related illness and death, but what about other organ systems and diseases connected to them? 

by Naida Salkovi?

Skin and Protection

Eczema is the most common form of dermatitis. [1] Eczema or atopic dermatitis (AD) is characterized by episodes of itchy rash that significantly impacts quality of life. It is the most common skin disease in the world. [1, 2] Eczema is characterized by immunoglobulin E mediated sensitization to allergens, both food and environmental. [3] Therapy for AD can be treated pharmacologically with the usage of different drugs (topical corticosteroids and antihistamines) and conventionally, which includes avoidance of irritants and potential allergens. [3]  Skin is the organ that has the most contact with the environment and the main function of skin is protection. Skin protects from different external factors, microorganisms, chemicals, temperature and UV light. [4] Eczema affects skin’s ability to protect itself from environmental factors.

Eczema And Environment

Eczema outburst can be worsened by different factors. Background of eczema is complex  and AD is especially sensitive to climate factors such as heat waves and air pollution. [2] A changing climate can cause changes in seasons, causing longer springs and summer with higher temperature and higher CO2 concentrations. These can have an effect on human exposure not only to pollen but also to other allergens, which can increase cases of allergy-related problems. [5]

In addition to considering the allergic aspect of the disease, it is important to mention the impact of UV light on the skin, and the possible harmful effect on eczema. UV radiation has some benefits on human health such as mediating synthesis of vitamin D and endorphins. [6] Because of this effect, UV radiation is used as a type of therapy for some skin conditions. However, high levels of UV exposure cause DNA damage of skin cells, leading to apoptosis and ultimately, the skin barrier is impaired. [7] The International Agency for Research on Cancer (IARC) classifies UV radiation as human cancerogenic. Due to climate change, there is a decrease in stratospheric ozone layer and consequently there is an increase in UV radiation, especially in UV-B. [8] UV-B radiation are invisible rays that are part of energy that comes from the sun, UV-B radiation causes several skin conditions, such as sunburn, thickening of skin layers and is connected to melanoma and other skin cancers. [9]

Predictions for Earth’s global average temperature by the end of the 21st century is that it will rise on average by 5 °C. [10] Raising temperature and heat waves result in sweat and all of this can cause an itch-scratch cycle ending in exacerbation of eczema symptoms. 

Research Gaps

Unfortunately, there is still a gap in research with climate effects on this disease. This topic still remains under researched and with the particularity of the disease, it is challenging to design research. Considering ways of therapy, when one of the most important steps for curing eczema is avoiding pollutants, this disease could in future have even more outburst with worse clinical cases. 

References:

[1] Laughter MR et al. The global burden of atopic dermatitis: lessons from the global burden of disease study 1990–2017. Br J Dermatol. 2021; 184(2): 304-309.
[2] Langan SM et al. Atopic dermatitis. Lancet. 2020; 396(10247): 345-360.
[3] Sohn A et al. Eczema. Mt Sinai J Med. 2011 Sep-Oct;78(5):730-9. doi: 10.1002/msj.20289. 
[4] Chuong CM et al. What is the ‘true’ function of skin? Exp Dermatol. 2002 Apr;11(2):159-87. doi: 10.1034/j.1600-0625.2002.00112.x.
[5] El-Sayed A, Kamel M. Climatic changes and their role in emergence and re-emergence of diseases. Environ Sci Pollut Res Int. 2020 Jun;27(18):22336-22352. doi: 10.1007/s11356-020-08896-w.  
[6] D’Orazio J et al. UV radiation and the skin. Int J Mol Sci. 2013 Jun 7;14(6):12222-48. doi: 10.3390/ijms140612222. 
[7] Thyssen JP et al. Potential role of reduced environmental UV exposure as a driver of the current epidemic of atopic dermatitis. J Allergy Clin Immunol. 2015; 136(5): 1163-1169.
[8] European climate and health observatory. Ultraviolet radiation. 2024. https://climate-adapt.eea.europa.eu/en/observatory/evidence/health-effects/uv-radiation
[9]   IARC Working Group on the Evaluation of Carcinogenic Risks to Humans. IARC Monographs on the Evaluation of Carcinogenic Risks to Humans, No. 100D. 2012. https://www.ncbi.nlm.nih.gov/books/NBK304366/ 
[10] Copernicus: 2023 is the hottest year on record, with global temperatures close to the 1.5°C limit.”Copernicus, Jan. 9, 2024. https://climate.copernicus.eu/copernicus-2023-hottest-year-record