Hard Water and Eczema. What’s the Correlation?

Does hard water contribute to eczema? Yes, for some children. Can you do something about it? We need more research.

Researchers have long suspected that water hardness might impact the severity of eczema. But the results of research studies have been mixed. As early as 2007, Spanish researchers concluded that hardness of water influenced eczema outcomes for 6–7-year-olds, but the well-designed EAT study in 2011 of 1303 infants in the UK found no association.

Still, epidemiologists continued to note that geographic areas with the hardest water had a greater incidence of eczema and researchers continued to study it. A 2020 review of the literature showed “there was a positive association between living in a hard water area and AE in children” in seven studies.

So why is there such conflicting information? A 2019 study may provide an answer. Researchers looked again at the data obtained in the 2011 EAT study in the UK. But this time they looked at children with a FLG mutation who lived in hard water areas. They discovered that in kids with the mutation, common in 30-50% of eczema cases, there was a threefold increased risk of developing eczema. For children without the mutation, there was no increased risk.

The obvious solution would seem to be adding a water softening filtration system to the homes of high-risk babies if they live in a hard water area. However hard water systems for an entire home are expensive. And, so far, the 2 studies that have examined their effectiveness have shown “there is no evidence that domestic water softeners improve objective disease severity in established AE.”

With the new information about the FLG gene mutation, an interventional study is needed to see whether water softeners would reduce the risk of developing in hard water areas of the world.

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