The impact of climate change on skin

Author: Dr Kirsten Due, General Practitioner, South Australia, Australia. Reviewed by Greg Miles, former Kakadu Chief Ranger and Park Naturalist, Northern Territory, Australia. DermNet New Zealand Editor in Chief: A/Prof Amanda Oakley, Dermatologist, Hamilton, New Zealand. December 2017.


What is climate change?

Climate change is a lasting alteration in patterns of weather caused by factors such as oceanic circulation, variations in solar radiation, plate tectonics, volcanic eruptions, and human factors. These may impact global or local temperature, humidity, rainfall, and weather extremes.

Colloquial use of the term “climate change” specifically refers to environmental changes caused by human factors, including global warming due to the production of gases that may trap heat in the atmosphere —­ carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O) and fluorinated gases.

Climate change has been called a “risk-multiplier” rather than a risk-generator or risk factor, due to it worsening pre-existing climate-related health concerns.

Climate influences a wide range of systemic diseases and conditions. Heat exposure, a combination of air temperature, humidity, air movement and heat radiation, can present an environmental hazard. The most common measures used to describe heat stress are the wet bulb globe temperature (WBGT), and universal thermal climate index (UTCI). A WBGT of 29 degrees has been shown to reduce work performance and to cause a wide variety of respiratory, cardiac and gastrointestinal diseases. 

As skin is exposed to the environment, it is especially vulnerable to increased heat and humidity. In this article, we describe the effects of a warmer environment on cutaneous infections and inflammatory diseases of the skin. 

Who are most vulnerable to the impact of a hotter environment?

  • Infants and children
  • Older people
  • Pregnant women
  • Outdoor workers and athletes
  • Indoor workers in an environment without cooling
  • Tourists or those unfamiliar with specific local heat risks
  • People with chronic medical conditions such as renal disease and alcohol dependence
  • People with diseases that impair awareness, mobility and behaviour (such as Parkinson disease, dementia, developmental delay).
  • Families and nations under financial stress and unable to adjust their environment 
  • People living in urban areas, because cities absorb, generate and retain more heat than rural areas
  • People living in homes not designed to reduce heat stress 
  • The socially disadvantaged (suffering from low economic status, homelessness or social isolation)

Cutaneous infection associated with warmer climate

Warmer conditions lead to a greater prevalence of cutaneous infections, including:

One study showed that for every 1°C rise in average temperature, the rate of hand foot and mouth disease increased by 10% and for every 1% increase in relative humidity (under 65%) the rate increased by 6.6%.

Infections prevalent in a warm climate

Vector borne disease

Mosquitoes, ticks, and fleas are vectors that carry pathogenic virusesbacteria, and protozoa, which can be transferred from one host (for example a mosquito) to another (for example a person or animal). Temperature plays an important role in the spread of vectors and vector borne disease. Warmer conditions lead to faster replication of certain viruses and vectors and increased rates of transmission.

Tick-borne infection 

Mosquito-borne infection

  • Malaria
  • West Nile virus
  • Dengue
  • Zika virus
  • California serogroup viruses 
  • Eastern equine encephalitis 
  • St. Louis encephalitis 

Flea-borne infection

Arthropod bites

Waterborne disease

Heavy rainfall and flooding often leads to outbreaks of waterborne disease, which are predicted to increase with climate change. Water sources may undergo increased contamination from flooding or become stagnant from drought. Flooding causes disease to spread as people move en masse to seek dry ground.  

Climate factors have been identified as important in outbreaks of the following waterborne diseases:

Foodborne disease

Flooding and droughts may lead to lack of fresh water for washing and cooking, especially in resource-poor nations. Warmer waters can cause outbreaks of shellfish-borne disease, such as Vibrio parahaemolyticus.

Mycotoxins

Increases in temperature and humidity cause food to decay and thus increased consumption of mycotoxins, which are metabolites of moulds. Mycotoxins may also cause disease by penetrating through the skin.

  • About 4.5 billion persons living in developing countries are chronically exposed to largely uncontrolled amounts of aflatoxin from aspergillus species (found in corn, peanuts and decaying vegetation).
  • Aflatoxin can cause liver disease, growth restriction in children and animals, cancer and immunosuppression leading to vaccination failure and decreased resistance to infectious disease.
  • Other mycotoxins have been associated with skin irritation and rashes. 

Phycotoxins

Phycotoxins are potent natural toxins produced by some marine algae and cyanobacteria species. Outbreaks or algal blooms are often colloquially known as as “red tides” or “green tides”. Seafood intended for human consumption can be contaminated in massive quantities.

    • Adverse health effects associated to phycotoxins and HABs can occur through oral, respiratory or dermal exposure.
    • Human intoxications are often misdiagnosed and therefore not reported to public health authorities.
    • Several phycotoxins are neurotoxic, potentially lethal, and associated with chronic morbidity.
    • Some cyanobacteria species produce phycotoxins that are dermatotoxins. These include;
      • Aplysiatoxins — which cause respiratory symptoms and skin irritation
      • Lyngbyatoxin — which case smooth muscle contraction and skin irritation. 
Algal blooms

Thermal injury

Warmer climate and hot surfaces, bushfires and building fires may lead to thermal burns.

Exposure to ultraviolet radiation

Measured levels of ultraviolet radiation are mainly independent of heat and humidity. However, higher outdoor temperatures in previously temperate climates might result in people wearing less clothing and spending longer periods outdoors, and thus increase exposure of the skin to ultraviolet (UV) radiation. 

UV damage includes:

Effects of ultraviolet radiation on the skin

Inflammatory skin diseases

Inflammatory skin diseases aggravated by hot conditions

Barriers to long term projections about interaction of climate factors and disease

Better early warning systems and prediction tools would enable prevention and management of disease epidemics — including those affecting the skin.

Barriers to making long term epidemiological assessments and projections include:

  • Paucity of disease data 
  • Changing health systems, socioeconomic status and land use 
  • Prolonged timescale – it is difficult to assess changes in climate without data of consistent quality over decades and centuries of weather events
  • Diagnostic inaccuracy and changing disease case definitions  
  • Poverty – the countries which support the poorest and most vulnerable populations are likely to suffer most from climate change. 

 

Related Information

References

  • Levy, S, Patz, J, 2015. Climate Change and Public Health. 1st ed. New York: Oxford University Press.
  • McMichael, A. 2017. Climate Change and The Health of Nations: Famines, fevers and the fate of populations. 1st ed. New York. Oxford University press.
  • Lupi, O, Hengge, U. 2017. Tropical Dermatology. 2nd ed. Edinburgh. Elsevier.
  • The Health Practitioners Guide to Climate Change: Diagnosis and cure. Edited by Griffiths, J, Rao, M, Adshead, F and Thorpe, A. 2009. London. Earthscan.
  • NOAA. 2012. NOAA History: A Science Odyssey [ONLINE] Available at: http://www.history.noaa.gov/index.html<. [Accessed 12 July 2017].
  • United States Environmental Protection Agency. 2017. Greenhouse Gas Emissions. [ONLINE] Available at: https://www.epa.gov/ghgemissions/overview-greenhouse-gases. [Accessed 31 July 2017]
  • Najera J, Kouznetsov R, Delacollette, C. 1998. Malaria Epidemics, Detection and Control Forecasting and Prevention.  WHO reference number: WHO/MAL/98.1084
  • Spergel, J. 2017. Role of allergy in atopic dermatitis (eczema). [ONLINE by subscription] Available at: https://www.uptodate.com/contents/role-of-allergy-in-atopic-dermatitis-eczema. [Accessed 10 May 2017]
  • Williams, J, Phillips, TD, Jolly, PE. Stiles, JK Jolly, CM Aggarwal D 2004. Human Aflatoxicosis in developing countries: a review of toxicology, exposure, potential health consequences, and interventions. American Journal Clinical Nutrition, 80(5), 1106-22.
  • Beard, C, Eisen, C, Barker, J, 2016. Vector-borne Disease: The Impacts of Climate Change on Human Health in the United States: A Scientific Assessment. U.S. Global Change Research Program, Washington. 129-156.
  • Balato, N, Ayala, F, Megna, M, Balato, A, Patruno, C 2013. Climate Change and Skin. Journal Italian Dermatological Venerology, 148(1), 135-46.
  • Handbook of Occupational Dermatology edited by L. Kanerva, P. Elsner, J.E. Wahlberg, H.I. Maibach. 2013. 1st ed. USA: Maibach Springer Science & Business Media.

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