Do eczema bath products actually work?

Parents looking to help relieve their child’s eczema may as well leave additives out of the tub and stick with topical moisturizers and soap avoidance, concludes a new large-scale study.

Researchers investigated whether bath emollient additives are effective in treating eczema. Previously, there was little evidence on the efficacy of emollients in treating eczema, and Miriam Santer, MBBChir, MRCGP, PhD, associate professor of Primary Care Research at the University of Southampton, United Kingdom, and co-author of the report, says this is the largest trial to date conducted on the intervention.

The Bath Additives for the Treatment of Childhood Eczema (BATHE) trial was funded by the National Institute for Health Research (NIHR), and led by the University of Southampton, which worked in partnership with the University of Bristol, Cardiff University (Wales), and the University of Nottingham, United Kingdom. Published in the BMJ, the study enrolled 482 children across 96 medical practices. For the first 16 weeks of the study, families completed weekly questionnaires, then repeated the process every 4 weeks for the remainder of the year.

Children in the study were randomly allocated to 2 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.

Researchers found no significant difference in eczema severity between the 2 groups over the course of the study.¹ They also found no significant difference in bathing problems, such as redness or stinging, which affected about a third of the children in each group.

“The important point is that both groups were advised to continue with all other standard eczema treatments including soap avoidance, regular leave-on emollients, and corticosteroid ointments when required,” Santer says. “We found no difference in eczema outcomes between these 2 groups.”

Children in the study were given several emollient bath additives to try, and 31% bathed less than 3 times per week during the study, 33% bathed 3 to 4 times a week, and 36% bathed 5 or more times a week. The only difference noted was a small benefit in the use of bath additives in the children who bathed with bath additives 5 or more times per week, but this is unlikely to be clinically significant. There was no difference among children who bathed less frequently with additives, according to the report.

Another finding from the study was that 35% of children in each group reported at least 1 adverse event per week, including slipping in the tub or stinging and redness, for the first 16 weeks of the study, indicating no significant difference between the groups.

Although the study didn’t find evidence of additional relief from emollient bath products, Santer says the silver lining may be cost-savings and simplicity for parents and children.

“This is important for families of children with eczema as it simplifies treatment in that they no longer need to use emollient bath additives, although they should continue to use their other treatments, including leave-on emollients (moisturizers),” Santer says. “We hope that our findings will help clinicians and families to find simpler and more cost-effective regimens for managing with childhood eczema.”

Economically, the report found that annual treatment costs between the 2 groups were $240 US dollars per year in the group that added bath emollients, and $221 US dollars in the group that used no bath additives. Quality of life measurements were no different between the 2 groups, the report notes, revealing that families using bath additives would do so at a higher economic cost without any real benefit.

Whereas the study revealed that there is little benefit to using emollient bath additives, topical (leave-on) emollients are still recommended for eczema. “Families should be advised to continue to use leave-on emollients and any products that help them to avoid soap, such as emollients designed to be used as soap substitutes,” Santer says.

More research is needed to determine the comparative efficacy of different leave-on emollients and methods of washing in eczema, according to the report.

References:

1. 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.