A multicentre pragmatic randomised trial of the clinical effects of emollient bath additives (EBAs) in children with eczema has concluded that their benefits are at best limited.

Overall 483 children with eczema, aged 1 to 11 years, were enrolled in the trial from 96 practices in England and Wales. Children with very mild or inactive eczema over the past year were excluded. All participants had a Nottingham eczema severity score >5 ¹ and had a bath at least once a week.

A total of 265 were randomised to using EBAs and 218 to not using EBAs for a one-year period. The mean age of children was five years in both groups. Standard advice on leave-on emollient and soap substitute use and use of topical steroids was given to both groups.

The primary outcome was severity of eczema measured each week using the Patient-Oriented Eczema Measure (POEM) questionnaire.² Higher scores equate with more severe disease.

There was one withdrawal in the EBA group. There was no significant difference in POEM scores between the groups at 16 weeks. The POEM score was 0.41 points higher in the no-EBA group (95% CI: -0.27 to -1.10). Only scores >3 points are considered clinically significant.

Secondary outcomes were measured up to 52 weeks and included adherence to protocol, dermatitis family impact, quality of life measures, as well as number of eczema exacerbations, use of topical corticosteroids and topical calcineurin inhibitors (e.g. tacrolimus, pimecrolimus). No significant differences between the groups were identified. Protocol adherence was high in both groups.

Although no overall benefit was seen in the EBA group it is possible that EBAs may have had limited benefit in very frequent bathers (more than five baths per week), and in children under five years of age. The POEM scores in the no-EBA children in these sub-groups were 2.27 points (95% CI: 0.63-3.91) and 1.29 (95% CI: 0.33-2.25) higher respectively. However, the number of children in these subgroups was small. No significant difference in POEM scores with EBA use was observed between children with moderate or severe eczema.

No statistically significant difference in side effects was seen between the groups either.

Currently the mainstay of childhood eczema management requires the regular application of topical leave-on emollients, the use of soap substitutes, and the use of EBAs. While the evidence for the first two is robust that for the use of bath emollients is thin.

These findings suggest that EBAs are neither clinically effective nor cost effective. It has been estimated that EBAs account for one third of the cost of eczema treatments in the UK.

The study authors conclude:

‘This trial provides strong evidence that emollient bath additives provide minimal or no additional benefit beyond standard eczema care in the management of children with eczema.’

They add: ‘We cannot exclude the possibility of a small benefit among children bathing more than five times a week or among children aged less than five years, but differences are sufficiently small to be unlikely to be useful.’

Dr Chris Barclay

Santer M, Ridd MJ, Francis NA et al. Emollient bath additives for the treatment of childhood eczema (BATHE): multicentre pragmatic parallel group randomised controlled trial of clinical and cost effectiveness. BMJ 2018;361:k1332