Hard water can damage skin, cause eczema: study

Hard water can damage the skin barrier that protects us from external threats like bacteria and sunburns, and lead to the development of eczema, a study has shown.
Researchers from the University of Sheffield and Kings College London in the UK have discovered that exposing the skin to hard water damages the skin barrier and increases the sensitivity of the skin to potential irritants found in everyday wash products such as soap or washing powder.
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) which act as detergents or wetting agents making them insoluble, so they precipitate onto the skin.

Skin pH is normally acidic but hard water has high alkalinity which means it can raise the skin surface pH.
A shift towards alkaline pH disturbs the skins natural function as a physical barrier and leaves it prone to colonization by potentially pathogenic bacteria which can cause infection.
"By damaging the skin barrier, washing with hard water may contribute to the development of eczema - a chronic skin condition characterised by an intensely itchy red rash," said Simon Danby, from the University of Sheffield.

Patients with eczema are much more sensitive to the effects of hard water than people with healthy skin.

This increase in sensitivity is associated with a genetic predisposition to a skin barrier defect brought about by mutations in the gene encoding filaggrin.
Filaggrin is a structural protein important for the formation of our skins barrier to the outside environment. Up to half of all people with eczema carry a filaggrin gene.
The new study reveals the mechanism by which calcium and magnesium ions in hard water, surfactants, and filaggrin interact to damage the skin barrier unlocking new information about how exposure to hard water could potentially contribute to the development of eczema.
Symptoms of eczema include inflamed, dry skin and often secondary skin infections, which can affect any part of the body and every aspect of a persons life both physically and emotionally.

The team of researchers examined whether removing the calcium and magnesium ions using an ion-exchange water softener could mitigate the negative effects of hard water on the skin.
They found that using a water softener reduces the harmful effects of surfactants, potentially decreasing the risk of developing eczema.
"It is during the first few days and months of life that our skin is most susceptible to damage and most at risk of developing eczema," said Carsten Flohr from Kings College London in the UK.
"For that reason 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," said Flohr.

The study was published in the Journal of Investigate Dermatology.