Hard water can exacerbate symptoms of eczema, according to a new study.
There are 13 billion households in the UK supplied with hard water, including much of the south, south east and midlands.
Researchers at the University of Sheffield and King’s College London have found that this type of water damages the protective skin barrier, leading to the skin condition.
The skin barrier is our defence against outside threats such as bacteria or sunburn, but if it’s damaged it can increase sensitivity of the skin to potential irritants.
Traditionally these irritants have been everyday household items like soap or washing powder, but now the researchers have revealed simply washing with water could cause an issue.
This is because hard water contains high levels of calcium and magnesium ions that binds to particular surfactants – compounds used to make detergents.
It renders them insoluble, and so they precipitate onto the skin.
Because hard water is very alkaline, while skin is naturally acidic, it can raise the skin’s surface pH.
This means the physical skin barrier is disturbed, leaving bacteria to enter and 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 Dr Simon Danby, lead study author 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 skin’s barrier to the outside environment. Up to half of all people with eczema carry a filaggrin gene.
“This 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.”
Areas with soft water include Wales, Northern Ireland, Scotland, and much of the south west and north or England.
Also known as atopic eczema or atopic dermatitis, symptoms of eczema include inflamed, dry skin and often secondary skin infections.
It can affect any part of a person’s body and can severely impact on their daily life.