Is Soap and Skincare Making Your Eczema Worse? The Skin pH Connection

If you have eczema or dermatitis, you may have tried countless creams, avoided certain foods and followed every piece of advice you could find — but have you ever considered that your soap or moisturiser could be hampering your skin's natural healing processes?

Image: hand with unidentified skin cream. What you put on your skin matters more than you might think.

 

Your skin has a natural defence system — and pH is at the heart of it

Healthy skin is naturally acidic, with a pH below 5.0 and an average of around 4.7 (Lambers et al., 2006). This acidity — known as the acid mantle — is not a quirk of biology. It is essential. It protects the skin against harmful bacteria, supports the skin barrier and helps beneficial microorganisms adhere to the skin's surface (Li et al., 2023; Lambers et al., 2006).

Even a small rise in skin pH can set off a chain reaction: the skin's natural defences against bacteria weaken, skin cells shed too quickly, and inflammation is triggered — changes that are commonly seen in eczema-prone skin (Ng et al., 2024).

What happens when skin pH rises too high?

A skin pH above 5.5 has been linked to a range of inflammatory and infectious skin conditions, including eczema, acne, dry skin, seborrhoeic dermatitis, ichthyosis vulgaris, candidiasis and nappy rash (Brooks et al., 2025; Hülpüsch, 2020).

It also creates conditions that favour the growth of Staphylococcus aureus (S. aureus) — a bacterium commonly found on eczema-prone skin that is strongly associated with flares and infection (Hülpüsch, 2020).

So what raises skin pH in everyday life? Two of the most common culprits are surprisingly ordinary: tap water and soap.

Tap water typically has a pH of 6.5–8.5, and soap ranges from 7.5–10.5 — both significantly more alkaline than healthy skin. After washing, skin surface pH can temporarily rise above 7.5, disrupting the microbiome and creating an opportunity for harmful bacteria to take hold (Lambers et al., 2006; Lukić et al., 2021; Brooks et al., 2025).

If you have eczema with recurrent skin infections, it could be a pH problem and your "pH balanced" skincare won't save your skin. It might even make it weaker.  

Does skin pH recover after washing?

Yes — but only if you have healthy skin, and not instantly, and not without consequence. While skin pH may return to its natural baseline within a few hours if your skin is healthy, that recovery window leaves the skin temporarily vulnerable to infection and irritation (Schmid-Wendtner & Korting, 2006).

For people with eczema whose skin pH may stay elevated, repeated daily exposure to alkaline soaps and skincare products may persistently impair the skin's ability to repair itself.

What about bleach baths?

Bleach baths are commonly recommended for infection control in eczema, but bleach is also highly alkaline. This raises an important question: could regular bleach baths inadvertently increase the risk of recurrent infections by disrupting the skin's microbiome?

The research has not yet fully answered this, and we are not suggesting you discard the bleach or the bath water just yet — as you can use low pH skincare to help the skin recover faster.

The surprising problem with "pH balanced" skincare

Here is something that may surprise you: skincare labelled "pH balanced" is not necessarily skin-friendly. A study on ageing skin, which shares many of the same barrier and pH challenges as eczema-prone skin, found that products labelled pH balanced (around pH 5.5) actually pushed epidermal pH into an unhealthy range. In contrast, genuinely low-pH skincare restored skin pH to within a healthy range (Blaak et al., 2011).

What about skincare not labelled 'pH balanced', are they good or bad for eczema? 

It depends. Creams and lotions that contain water will have a pH that may be even higher, like creams containing vitamin C, which are formulated at around pH 6.0 to ensure vitamin stability, which may damage the skin barrier. 

Note that some creams, like Wonder Zinc, do not have a pH as they have a very low water content — water is required to have a pH reading. These creams can be beneficial for the skin in different ways, but they won't fix a pH problem.

Occlusive ointments like paraffin (petroleum) may increase the skin pH due to their occlusive nature, so they should not be used too frequently. 

In contrast, research shows that low-pH skincare, with a pH around 4.5 to 4.7, helps to restore the skin barrier, may reduce inflammation and protect the skin's resident microbiome — making it a valuable addition to your routine, particularly after bathing (Proksch, 2018).

Table 1. Key differences between healthy and eczema-prone skin, with clinical recommendations.

Moisturisers with lactic acid: a targeted approach to infection control in eczema

S. aureus (known as "staph") colonises eczema-prone skin, with elevated levels strongly associated with flares (Kong et al., 2012). It thrives at a skin pH of 6.0–7.0 — precisely the elevated pH range commonly seen in eczema-prone skin.

So what can you do to protect your skin if you have eczema?

Look for lactic acid in your skincare products: Staph's growth is inhibited in a lactic-acid-rich environment at around pH 4.5 (Costa & Horswill, 2022; Rode et al., 2010). Lactic acid is naturally present in healthy skin as part of the skin's natural moisturising factor, but is often reduced in eczema-prone skin (Hülpüsch, 2020). When included in skincare at a low pH, lactic acid may be synergistic — a lower skin pH increases the proportion of lactic acid able to penetrate bacterial cell membranes, potentially disrupting S. aureus bacteria and reducing infection risk (Hayashi et al., 2021).

A word of caution: high concentrations of lactic acid can damage the skin barrier, so avoid scrubs and peels with lactic acid. Low concentrations, however, act as a gentle humectant and pH-adjusting agent. Look for it at the end of the ingredient list.

A low-pH moisturiser containing a low concentration of lactic acid may be a simple but meaningful addition to an eczema care routine. An example of a low pH moisturiser with lactic acid is Eczema Friend or 24-Hour Rescue. 

Important: If you suspect your rash is infected, see your doctor as infections require medical attention. Use low pH skincare to keep your skin protected during and after antibiotic use. 

A simple but overlooked piece of the puzzle

The evidence suggests that everyday cleansing and moisturising habits may be an unrecognised and easily modifiable trigger for people with eczema. Switching to a soap-free, low-pH cleanser and applying a properly formulated low-pH moisturiser twice daily, could help to reduce infection risk, support barrier repair and improve quality of life.

It is a small change, but for skin that is struggling, it could make a meaningful difference.

Shop low pH skincare at skinfriend.com 

This blog was written by Karen Fischer, nutritionist, researcher and author of The Eczema Diet and The Eczema Detox. 8 June 2026.

Skincare for eczema low pH acidification acid mantle

References

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