Eczema and swimming — chlorine, saltwater, and the after-swim protocol

Swimming is an activity that many people with eczema approach with anxiety — sometimes abandoning it entirely after a bad reaction, sometimes managing through it without ever optimising what they do before and after.

The relationship between water, chlorine, salt, and eczema skin is nuanced, and with the right protocol around it, swimming doesn't have to be a trigger.

Chlorinated pools

Chlorine is a disinfectant and a potential irritant, but its relationship with eczema is more complicated than simply "chlorine is bad." Some studies have found that regular swimming pool exposure is associated with improved eczema outcomes in children — possibly because the controlled moist environment hydrates the skin and the cool water reduces itch. Other studies show worsening in some individuals.

The variability comes from several factors. Chlorine reacts with organic matter in the pool — sweat, urine, skin cells — to form chloramines, which are more irritating than free chlorine. Poorly maintained pools with high chloramine levels are more problematic than well-maintained ones. The distinctive "chemical" smell of a pool is chloramines, not chlorine — a strong smell indicates high chloramine levels.

pH also matters. Pool water is slightly alkaline (typically pH 7.2–7.8), which can disrupt the skin's naturally acidic pH (4.5–5.5). This pH shift reduces the skin barrier's effectiveness and increases permeability to other irritants in the water.

What to do before swimming

Apply a thick layer of emollient to all skin before entering the pool. This creates a temporary barrier that reduces chlorine contact with the skin surface and slows the barrier-disrupting effect of the water. This is not waterproof — the emollient washes off during swimming — but it meaningfully reduces the extent of contact during the swim.

Wearing a rash guard or swimming costume that covers more skin reduces the total skin surface area in contact with pool water. For eczema affecting the torso or limbs, this is a practical approach that doesn't require explaining to pool management.

What to do after swimming

Shower immediately after leaving the pool — with lukewarm water — to remove chlorine residue before it dries on the skin. A brief shower is sufficient; a long shower removes more of the skin's natural oils than the chlorine you're trying to remove.

Apply emollient generously within three minutes of drying. This is the most important post-swim step. The skin is more permeable after swimming — the protective barrier has been partially disrupted — and this window is when emollient is most effective.

Saltwater

Sea swimming is better tolerated by most people with eczema than chlorinated pools. Seawater has a natural salt concentration of approximately 3.5%, and there is some evidence that magnesium-rich saltwater — particularly in the Dead Sea — improves eczema outcomes. The mechanism is thought to involve enhanced skin hydration and anti-inflammatory effects of magnesium.

The caveat is that saltwater can also sting and irritate already broken or inflamed skin. If you have active weeping eczema, saltwater will be painful. The emollient-before, rinse-and-reapply-after protocol is the same as for pool swimming.

Managing the environment