RCGP Research Paper of the Year 2018: The BATHE Study

01 November 2019

Dr Miriam Santer, GP and Associate Professor in Primary Care Research at the University of Southampton. Parent of children with mild eczema. 

The BATHE study, which informed the RCGP Research Paper of the Year, was a randomised controlled trial that included 482 children aged one to 11 years across 96 general practices in England and Wales over a 12-month period and was by far the largest trial of emollient bath additives to date.

Children were randomly allocated to two groups: one group was asked to use bath additives for a whole year and the other was asked not to use them for a whole year. Families or carers completed short questionnaires known as a patient-oriented eczema measure (POEM) weekly for the first 16 weeks, then every four weeks from 16 to 52 weeks.

Most children had mild or moderate eczema, 62 had severe eczema, and half were using corticosteroid cream.

Only 74% of the intervention group used emollient bath additives at every bath, raising questions around adherence to treatment, both within and outside of the trial environment. The control group were asked not to use emollient bath additives, though 7% did.

Key messages and implications for clinical practice

The BATHE trial found that pouring emollient additives into the bath provided no additional benefit over standard eczema care; there was no difference in outcomes between the two groups included in the study.

Standard care in the BATHE trial included advice to use leave-on emollient as a soap substitute to standardise washing. Therefore, the trial did not compare the effectiveness of different regimens of soap substitution and the authors concluded that further research is needed into optimal regimens for leave-on emollient and soap substitutes.

It is crucial that children with eczema continue to receive leave-on emollients on prescription, as these have been shown to reduce flare-ups and reduce the need for topical corticosteroids. Families also need advice on soap avoidance, either through using leave-on emollients or soap substitute emollients. But we no longer need to tell them to pour emollient bath additives into the bath.


We strongly object to the implication that the BATHE trial provides evidence to stop prescribing all bath and shower products, as suggested by some Clinical Commissioning Groups (CCGs).

To be clear, we support initiatives to reduce the prescribing of emollient bath additives poured directly into the bath water, but not a reduction in the ability of patients to obtain appropriate prescriptions for soap substitutes.

Further information

Links to a short video summary, the BMJ article and the authors’ response to recent NHS England guidance can be found on the BATHE website: www.southampton.ac.uk/bathe  


This work was funded by the National Institute for Health Research Health Technology Assessment Programme (11/153/01)

The views and opinions are those of the authors and do not necessarily reflect those of the HTA, NIHR, NHS or the Department of Health & Social Care


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