MedicalResearch.com Interview with:
Dr. Simon G. Danby, PhD
Independent Research Fellow
Sheffield Dermatology Research,
Department of Infection & Immunity & Cardiovascular Disease,
Faculty of Medicine, Dentistry & Healthy,
University of Sheffield
MedicalResearch.com: What is the background for this study? What are the main findings?
Response: Living in a hard water area has been widely associated with a higher risk of developing atopic eczema, a chronic skin condition characterized by an intensely itchy red rash, however the reasons for this association were unclear. We therefore conducted a study to determine how hard water contributes to the development of this condition.
We found that exposing the skin to hard water damages the skin barrier – which is our defense against outside threats such as bacteria or sun burn – and increases the sensitivity of the skin to potentially irritant surfactants found in everyday wash products. This is because hard water contains high levels of calcium and magnesium ions that bind to surfactants, such as sodium lauryl sulfate (SLS) and sodium lauryl ether sulfate (SLES), making them insoluble so that they precipitate onto the skin.
Hard water also has a high alkalinity, meaning that it can help raise skin surface pH, so that it becomes more alkaline. Skin pH is normally acidic, and a shift towards alkaline pH disturbs the skins natural function as a physical barrier and leaves it prone to colonization by potentially pathogenic bacteria. By damaging the skin barrier, washing with hard water may contribute to the development of atopic eczema.
Importantly, patients with eczema were much more sensitive to the effects of hard water than people with healthy skin. This increase in sensitivity was associated with a genetic predisposition to a skin barrier defect brought about by mutations in the gene encoding filaggrin (FLG loss-of-function mutations). Filaggrin is a structural protein important for the formation of our skin’s barrier to the outside environment. Up to half of people with eczema carry a filaggrin gene. This new study illustrates the mechanism by which calcium and magnesium ions in hard water, surfactants and filaggrin interact to damage the skin barrier.
We report that removing the calcium and magnesium ions using an ion-exchange water softener could mitigate the negative effects of hard water on the skin. The implication is that using a water softener could help reduce the incidence of eczema by reducing the harmful effects of covert irritants in everyday wash products.
MedicalResearch.com: What should clinicians and patients take away from your report?
Response: That the way we care for our skin, including the products and the water we use, has a significant impact on the health of our skin. Further research is needed to identify the best approach to caring for our skin from birth.
MedicalResearch.com: What recommendations do you have for future research as a result of this study?
Response: We are now embarking on a pilot trial to investigate whether installation of a domestic water softener around the time of birth can prevent skin barrier breakdown and eczema in those living in hard water areas.
The Softened Water for Eczema Prevention (SOFTER) trial will be undertaken by Dr Flohr and his team from King’s College London and the National Institute for Health Research (NIHR) Biomedical Research Centre at Guy’s & St Thomas’ NHS Foundation Trust in collaboration with the University of Sheffield team and colleagues from the University of Dundee, the Centre of Evidence-Based Dermatology at Nottingham University, Imperial College London, the National Institute for Health (Bethesda, USA), and Amsterdam Medical Centre.
MedicalResearch.com: Is there anything else you would like to add?
Response: The study was funded by Harvey Water Softeners
The paper, The Effect of Water Hardness on Surfactant Deposition Following Washing and Subsequent Skin Irritation in Atopic Dermatitis Patients and Healthy Controls, is published in the Journal of Investigative Dermatology. DOI: 10.10.16/j.jid2017.08.037
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The Effect of Water Hardness on Surfactant Deposition Following Washing and Subsequent Skin Irritation in Atopic Dermatitis Patients and Healthy Controls
Danby SG1, Brown K2, Wigley AM3, Chittock J4, Pyae PK5, Flohr C6, Cork MJ7.
J Invest Dermatol. 2017 Sep 12. pii: S0022-202X(17)32938-X. doi: 10.1016/j.jid.2017.08.037. [Epub ahead of print]
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