Weekly versus daily bathing for people with eczema: results of the Eczema Bathing online randomized controlled trial

Abstract

Background Questions about washing are a high priority for people with eczema (also known as atopic dermatitis and atopic eczema), but they are rarely the focus of randomized controlled trials (RCTs). Objectives To assess the impact of weekly vs. daily bathing in people with eczema in the first of a series of eczema citizen science online trials in the UK. Methods This was a pragmatic two-arm parallel-group superiority RCT. People with self-reported eczema aged ≥ 1 years were eligible, excluding those with very mild eczema [Patient Orientated Eczema Measure (POEM) score ≤ 2]. Participants were allocated (1: 1) using minimization, balancing on eczema severity (POEM), age and usual method of bathing to either the weekly bathing group (bath or shower once or twice weekly) or the daily bathing group (bath or shower ≥ 6 times weekly) for 4 weeks. Participants were not blinded to their allocation. The primary outcome was participant-reported eczema symptoms collected weekly over 4 weeks using POEM (range 0–28, where higher scores indicate more severe eczema). The trial was registered with ISRCTN on 22 November 2023 (https://www.isrctn.com/ISRCTN12016473). Results In total, 438 people with eczema (108 of whom were aged < 16 years) were randomized between 29 January and 8 July 2024: 218 to daily bathing and 220 to weekly bathing. The primary analysis included 195 participants (89.4%) allocated to daily bathing and 193 (87.7%) to weekly bathing who completed at least one follow-up questionnaire. Mean (SD) POEM scores at baseline and at 1, 2, 3 and 4 weeks were 14.5 (5.7), 11.7 (5.9), 12.2 (5.9), 11.7 (6.7) and 11.6 (6.5), respectively, in the daily bathing group and 14.9 (6.3), 12.1 (6.8), 11.3 (6.7), 10.5 (7.0) and 10.6 (7.2), respectively, in the weekly bathing group. The adjusted difference in mean POEM score over 4 weeks for weekly vs. daily bathing was –0.4 (95% confidence interval –1.3 to 0.4; P = 0.30). Process evaluation data highlighted participants’ experiences of making changes to bathing routines, including barriers to following the allocated routine. No serious unintended effects or harms were reported. Conclusions The trial found no evidence of a difference in eczema symptoms between bathing or showering weekly vs. daily. These results are helpful for people with eczema, giving them the freedom to choose what suits them best.