Bleach bathing is a common adjunctive treatment recommended to treat atopic dermatitis (AD), but its efficacy, safety and mechanism of action is uncertain. 

We searched MEDLINE, EMBASE, CENTRAL, GREAT from inception to December 29, 2021, for randomized controlled trials (RCTs) assigning patients with AD to bleach versus no bleach baths. Paired reviewers independently and in duplicate screened records, extracted data, and assessed risk of bias (Cochrane version 2) and GRADE quality of evidence. We harmonized individual patient data and did Frequentist and Bayesian random effects meta-analyses. PROSPERO registration CRD4202123848.

10 RCTs (6 published, 4 unpublished) enrolled 307 participants (mean of mean age across trials 8.5 years [range of means, 4.7-12.0], EASI baseline mean of means 27.57 (median standard deviation (SD) across trials, 10.74)) for a median duration of 6 weeks [range 6 – 12]. Bleach baths probably improve AD severity compared to water baths (ratio of means 0.78 [95% credible interval (CrI) 0.59-0.99]; EASI mean difference -6.04 [95% CrI -11.30, -0.28]; moderate certainty) and lead to little to no difference in skin Staphylococcus aureus bacterial growth (relative risk (RR) 0.91 [95% confidence interval (CI) 0.75, 1.11]; risk difference (RD) -0.06 [-0.19, 0.06]) or adverse events (RR 0.98 [95% CI 0.60, 1.61]; RD 0.03 [95% CI -0.05, 0.10]); all low certainty. Adverse events, mostly dry skin and irritation, along with itch, patient-reported disease severity, sleep quality, AD-related quality of life, and risk of AD flares were not clearly different between groups and of low to very low certainty. ​

In patients with moderate to severe AD, bleach baths reduce clinician reported severity by 22% compared to baseline. One in 10 will likely improve severity by 50%. The evidence for other patient-oriented outcomes such as adverse events, patient reported itch, patient-reported disease severity, sleep quality, AD-related quality of life, or risk of AD flares are uncertain. These findings support the need for a larger clinical trial to fully inform the benefits and harms of this common and easily available intervention.