Eczema, or atopic dermatitis, is a chronic inflammatory disorder characterized by intense itching and a compromised skin barrier function. This impairment means the skin cannot effectively retain moisture or block irritants, leading to increased sensitivity and flare-ups. The relationship between this fragile skin and salt water is confusing, as some people find it soothing while others experience immediate irritation. Understanding the concentration and mineral makeup of the water is necessary to determine its actual effect on eczematous skin.
The Dual Nature of Salt Water’s Impact
Salt water is not uniformly beneficial or detrimental to individuals with eczema; its impact depends heavily on the specific composition and concentration of dissolved minerals. Ocean water, which primarily contains high levels of sodium chloride, can initially feel therapeutic due to its mild antiseptic qualities on unbroken skin. However, the high sodium concentration often leads to significant dehydration.
Once the water evaporates, it leaves behind concentrated salt crystals that draw moisture out of the skin cells, exacerbating dryness. This drying effect can quickly lead to irritation and stinging, especially on cracked or open lesions.
In contrast, certain therapeutic salt waters, such as those used in balneotherapy, are rich in other minerals like magnesium and potassium. Magnesium, in particular, has been shown to improve the skin barrier function, enhance hydration, and reduce inflammation in atopic dry skin. Studies have demonstrated that bathing in magnesium-rich salt solutions can lead to a measurable reduction in skin roughness and redness. This suggests that the mineral content, rather than just the presence of salt, dictates the potential for true relief.
How Salt Water Affects the Skin Barrier
The skin barrier, primarily the stratum corneum, functions as the body’s protective layer, but in eczema, this layer is defective and leaky. Exposure to high-salinity water initiates a process driven by osmotic pressure. When high-salt ocean water contacts the skin, it pulls essential moisture from the skin cells to equalize the concentration gradient.
This moisture loss directly contributes to transepidermal water loss (TEWL), a measure of water escaping through the skin, which is already elevated in eczema patients. The resulting dehydration stiffens the skin and increases its susceptibility to cracking and inflammation. This effect of water being drawn out often outweighs the mild anti-inflammatory benefits that sodium chloride might offer.
The physical residue left behind also plays a role in continued irritation. As the water evaporates, microscopic salt crystals remain on the skin surface, acting as physical irritants that can mechanically chafe the already fragile epidermal layer. This abrasive action increases the likelihood of a flare-up. While salt water offers potential antiseptic properties, this benefit is often nullified by the intense drying and subsequent irritation if the salt is not promptly rinsed away.
Essential Care Before and After Water Exposure
Individuals with eczema can minimize the negative effects of salt water by incorporating a careful pre- and post-exposure routine. Before entering the water, apply a thick layer of a protective emollient or petroleum jelly, focusing on areas with active or broken skin. This creates a physical, water-resistant barrier that shields the skin from the high concentration of salt and helps lock in existing moisture.
After exiting the water, rinse the skin immediately and thoroughly with fresh, clean water to remove all salt residue. Rinsing for approximately 30 seconds helps prevent the salt from drying on the skin and starting the osmotic process of drawing out moisture. Pat the skin dry gently with a soft towel, avoiding any rubbing or friction that could irritate the skin.
The most important step is the immediate reapplication of a heavy moisturizer or prescribed emollient. This should occur within three minutes of drying the skin, often called the “3-minute rule,” to seal in the hydration absorbed during the rinse. Limiting the duration of exposure and avoiding peak sun hours also helps, as sun exposure can compound the drying effect.