Hard Water and the Skin

Hard Water and the Skin
Q&A with Hard water and the skin: Dr Justine Hextall FRCP Consultant Dermatologist based at the Tarrant Street Clinic in Arundel.

1. Why do you think hard water may be linked to more cases of skin conditions? What is the possible mechanism for hard water increasing eczema for example?

The mechanism is related to the effects of hard water on the skin barrier. Firstly hard water described as such due to high concentrations of magnesium and calcium ions, tends to be more alkaline, whilst the skin barrier is naturally acidic. If the pH of skin is changed it starts to disrupt barrier function. The skin barrier is very important as it helps to hold moisture in the skin and keep irritants,
infection and allergens out. Those with an eczema prone skin, are already vulnerable due in part to genetic variations in proteins in the skin barrier such as filaggrin, which makes the skin more prone to moisture loss etc.

2. What is the mechanism for washing with hard water and soap linked to dermatitis?

Increased skin barrier impairment? When we wash with hard water, the high calcium content reduces the solubility of surfactants (detergents) in soaps and shampoos such as sodium lauryl sulphates. These surfactants therefore tend to stay on the skin causing dryness and irritation and can impair barrier function. They have a similar effect on hair, leaving dry and dull. An eczema- prone skin, will be particularly prone to irritation from this process. It makes sense therefore that studies have shown an increased prevalence in eczema in hard water areas.

3. Could higher chlorine levels in tap water also help to increase skin irritation?

I don’t believe the concentration of chlorine in tap water is enough to cause significant irritation to skin. Certainly chlorine in swimming pools will definitely cause skin dryness and irritation, as such
immediately showering after swimming is advised, especially with atopic skin.

4. Would you recommend people filtering their water or softening their supply?

There has been an interesting study called the SOFTER study that recruited pregnant women with a family history of atopy ( so higher genetic risk of the infant developing eczema) in hard water areas and
randomised to two groups. One with a water softener installed and the other group a control. There were 39 in each arm, with 15% dropping out by 6 months post partum. At 6 months overall 40% of infants had
developed eczema, 48% in the control arm and 33% in the water softener group, showing a statistically significant benefit to use of water softeners in this high risk group. As such I feel it may be a beneficial device, particularly for atopic families. I would however like to see further studies with larger cohorts.

5. What about special soaps or products that reduce the impact of hard water?

Firstly I always recommend washing sensitive facial skin after the shower, for many reasons. Firstly the heat of shower water can reduce natural oils that help to protect the skin from moisture loss. Secondly, shampoos and shower gels are not created for delicate facial skin. By using a rich hydrating cleanser after the shower these surfactants in combination with hard water may be removed. I would then advise applying a hydrating serum that contains humectants such as hyaluronic acid and glycerin to damp skin to trap moisture. Afterwards apply a facial moisturiser that has ingredients such as shea butter and ceramides that mimic the natural oils and fats found in a healthy skin. This combination is ideal for soothing and hydrating an eczema-prone skin and helping to create a more robust skin barrier that will be able to withstand external aggressors such as hard water and surfactants. There are also some cleansers and shampoos that have been created to remove unwanted minerals from hair and skin, by binding them. I don’t have personal experience , but the mechanism of action makes sense and some seem to have good reviews.