Is Your Shower Making Your Eczema Worse?
If you have eczema, or live with someone who does, you may have noticed that flare ups sometimes seem to follow a shower rather than precede one. The skin that was manageable before a wash is red, itchy and inflamed afterwards. The natural response is to blame shower gel, shampoo or water temperature.
These are real factors, and they're worth addressing. But there's another shower related trigger that dermatologists and microbiologists have been paying increasing attention to, and it's one that most people with eczema have never been told about.
Why eczema skin is especially vulnerable
Healthy skin has a barrier function, a layer that keeps moisture in and irritants and pathogens out. In eczema, this barrier is compromised. Research has linked eczema to reduced levels of a protein called filaggrin, which plays a central role in maintaining the skin's structural integrity. When filaggrin is reduced, the skin holds moisture less effectively, becomes more permeable to irritants, and is more susceptible to infection.
The water quality factors most people know about
Hard water is increasingly well evidenced as an eczema trigger. A 2018 study from King's College London found a significant association between hard water exposure and eczema risk in children. Hard water contains higher levels of calcium and magnesium salts that deposit on the skin during showering, irritating an already compromised barrier.
Chlorine, added to mains water as a disinfectant, is another documented irritant. Research has shown that chlorine damages filaggrin, the same protein that's already compromised in eczema skin. Even in the concentrations used in domestic water supplies, regular exposure during showering can increase transepidermal water loss, meaning the skin loses moisture more readily after each shower.
The factor most people haven't considered
What receives far less attention is the bacterial content of the water as it leaves the shower head.
Research has consistently shown that domestic shower heads harbour significant bacterial communities in their internal biofilms, in concentrations more than 100 times higher than in the tap water entering them. Among the bacteria commonly found are Pseudomonas aeruginosa, Staphylococcus species and various Mycobacterium species.
Staphylococcus aureus is already well known as an eczema aggravator. Research has found that S. aureus colonises eczema affected skin far more readily than healthy skin, and its presence is strongly associated with flare up severity. Pseudomonas aeruginosa, another common shower head organism, is associated with folliculitis, an infection of the hair follicles that in people with eczema can trigger or worsen a flare.
What this means practically
If you or a family member has eczema that doesn't respond well to treatment, or that flares without an obvious explanation, your shower is worth examining as a potential contributor.
The shower head in most homes has been there for years, accumulating a bacterial biofilm that no amount of shower gel changes. Every shower exposes eczema affected skin to that bacterial community directly, through water contact, and indirectly, through the aerosol that surrounds a running shower.
Replacing a standard shower head with one that actively prevents bacterial biofilm formation won't cure eczema. But it may remove one chronic source of irritation and bacterial exposure that has been quietly contributing to the problem. It's a simple change. For families who have tried everything else, it seems worth trying this too.
Steve Bennett, Co Founder, Fereno
