Scrub a dub dub, eczema in the tub – what does the research say?

Rapid Eczema Trials team have been deciding which questions about washing are most important to people with eczema. But what does research already tell us about eczema and washing?

For people with eczema, there are lots of question marks over how to wash. And as it turns out… very little evidence to guide them! As a result, people often go through a ‘trial and error’ process to work out what works for them.

Science is about more than trial and error. It is about well-designed studies that help us learn what works for most people, most of the time. That doesn’t mean it will work for everyone – but it gives us a better chance of starting with the best option. To do this, we use ‘randomised controlled trials’. Trials randomly allocate people to treatments or strategies, and then look to see how outcomes in the groups receiving different treatment or strategies compare to each other. Laura (one of our researchers) and Devin (one of our citizen scientists) have teamed up to share with you what we’ve learnt about the evidence on bathing and eczema…

First up, here is Laura’s run-down of the randomised controlled trial evidence for the top three burning questions about eczema and bathing prioritised by the Rapid Eczema Trials community:

How often to wash?

Does anyone else remember the childhood torture of ‘bath day’? I still remember the exasperated faces of my parents as they wrestled me and my sister into the bath. For us, once a week was one bath too many, so I was surprised to learn from others in the Rapid Eczema Trials team that there can be a ‘mothers’ guilt’ if not bathing children daily. These days I am more partial to a bath and use an evening soak to unwind at the end of the day. How we wash is influenced by both cultural and familial practices, and I was really fascinated to hear from dermatologist Dr Michael Perkins who joined us one evening and spoke of how regular washing is a modern phenomenon – our ancestors wouldn’t be washing hardly as much. But what does this do to our skin?

Dr Van Halewijn and colleagues (1) found that international eczema guidelines offer conflicting advice. Whilst some guidelines suggest regular bathing to cleanse and moisturise skin, others caution that it can dehydrate the skin and cause irritation. Dr Koutroulis and colleagues [2]) published a study in 2014 that asked children (6 months to 10 years) with eczema to either wash twice a week or daily for 2 weeks. They found no difference in the children’s eczema, but we can’t take too much from these results as there was only 28 children included in the study. A more recent study by Dr Cardona (3) and colleagues in 2019 found that children (6 months – 11 years) twice daily washing followed by moisturising made eczema symptoms better compared to less frequent washing (twice weekly followed by moisturiser). Again, this is quite a small study with only 42 children taking part. We also have the extra question of whether it was more frequent washing or more frequent moisturising that helped improve the eczema.

What to wash my clothes with?

I always use non-bio, I don’t have eczema, but my mum told me that when I was a kid my skin would react to bio – so I have avoided it since. Member of the Rapid Eczema Trials team also had strong preferences for washing powders – this didn’t necessarily fall into camp bio or camp non-bio though, and seemed to be something that was personal, and everyone found a particular brand or type that worked for them and stuck to it.

A study by Dr Anderson and colleagues (4) asked adults with eczema (people taking part were white, mostly female and severe eczema was excluded) to use either bio or non-bio washing powder for 1 month and then they switched over to the other for a month and found that it made no difference to eczema symptoms or how often people needed to use their eczema treatment. Again, this was a small study of 25 people.

Use soap?

Based on conventional wisdom and guidance (5), lots of people with eczema tend to feel like they should avoid soap, and doctors will often recommend this too, but we haven’t come across any clinical trials that have tested whether this is true.

Here are some reflections on what this evidence means to Devin as a person living with eczema:

There is a very good chance that if you do not suffer from eczema yourself then you almost certainly know someone who does. So, with it being such a common issue, not just in the UK but globally, and it being widely reported that bathing has a likely effect on the skin and its condition, you might think there would be extensive research and guidance out there to help us. To the surprise of myself and the rest of the Rapid Eczema Trials team there unfortunately was not. Instead, the advice and information we found seemed to be contradicting and unclear, due to a lack of evidence backed information.

For some people, bathing is a regular part of their lives and it is part of their daily routine whether they have a shower, bath or a strip wash. The lack of clear answers means some of us could be making our condition worse without realising it. This is why it is so very important that the eczema community have evidence backed guidance to improve our wellbeing. With so much time and energy being spent on avoiding triggers to flare-ups, it would be amazing to have to worry about one less thing.

So where does this leave us?

The Rapid Eczema Trials team were left with a wide variety of choices when it came to designing their own research about bathing – previous studies haven’t been enough to provide conclusive answers and there are so many unanswered questions! Over the coming months, we will be working together to design an online trial that will answer at least one of these questions in a large, high-quality clinical trial – so do sign-up to receive our Rapid Eczema Trials news updates and keep in touch if you would like to find out more.

Written by Laura Howells (Senior Research Fellow at the Centre of Evidence Based Dermatology) and Devin Patel (RAPID Eczema Trials Citizen Scientist)

Originally published at blogs.nottingham.ac.uk

    References:
    1. Van Halewijn, K. F., et al. (2022). “Recommendations for emollients, bathing and topical corticosteroids for the treatment of atopic dermatitis: a systematic review of guidelines.” European Journal of Dermatology 32(1): 113-123.

    2. Koutroulis I, Petrova K, Kratimenos P, Gaughan J. Frequency of Bathing in the Management of Atopic Dermatitis: To Bathe or Not to Bathe? (2014) Clinical Pediatrics 53(7):677-681. doi:10.1177/0009922814526980

    3. Cardona, I. D., et al. (2020). “Frequent Versus Infrequent Bathing in Pediatric Atopic Dermatitis: A Randomized Clinical Trial.” J Allergy Clin Immunol Pract 8(3): 1014-1021.

    4. Andersen, P. H., et al. (1998). “Skin symptoms in patients with atopic dermatitis using enzyme-containing detergents. A placebo-controlled study.” Acta Derm Venereol 78(1): 60-62.

    5. National Institute for Health and Care Excellence (2007). “Atopic eczema in under 12s: diagnosis and management.” Retrieved 22 November 2022, from https://www.nice.org.uk/guidance/cg57.