In a literal version of “pouring salt on a wound,” a new study has found that sodium chloride may actually affect those with dry, cracked skin. The study, published in Science Translational Medicine, has shown that the skin of people with eczema, also called atopic dermatitis, contains more salt than the skin of those without the allergic condition.
Immune system cells called T-cells play an important role in allergic reactions, and with eczema, a sub-group of these cells (Th2 cells) overproduces specific proteins, leading to the parched skin itchiness that can sometimes bleed or become infected. Researchers from the Technical University of Munich demonstrated that high levels of salt can increase production of these proteins, while lower salt levels can reverse the process.
They also discovered that, during an eczema outbreak, the skin contains as much as 30 times more sodium than healthy skin. And certain bacteria (Staphylococcus aureus) – the concentration of which is elevated on skin with eczema, per previous research – thrive in a salty environment, increasing the infection risk.
What’s unclear at this point is how larger-than-normal amounts of salt make their way into the skin of people with eczema – is it how much you ingest, the way your body metabolizes it, or some other process? – so the possible effects of a high-sodium or low-sodium diet aren’t yet known.