Bleach baths may help patients with mild to severe atopic dermatitis

Regular use of bleach baths modestly improved atopic dermatitis severity among most patients with a good safety profile, according to a systematic review and meta-analysis published in Annals of Allergy, Asthma & Immunology.

Layla Bakaa, OSSD, a neuroscience student at McMaster University in Ontario, Canada, and colleagues wrote that bathing in dilute bleach — typically 0.25 to 0.5 cups of 5% to 6% bleach in a full bathtub (approximately 40 gallons of water) for a final concentration of 0.005%, applied for 10 minutes, two to three times per week — is a common adjunctive treatment for atopic dermatitis (AD).

To evaluate the safety and efficacy of bleach baths for AD, Bakaa and colleagues reviewed 12 reports that represented 10 randomized control trials. The trials comprised a total of 307 patients (median of mean age, 7.2 years; interquartile range, 4.7-12; 50.5% female) with mild to severe AD.

Based on data from eight studies, the researchers concluded that bleach baths “probably” improve AD severity compared with no bleach baths (ratio of means [RoM] = 0.78; 95% credible interval [CrI], 0.59-0.99). The studies showed effects as soon as 4 weeks from baseline.

The pooled probability for AD severity to improve by 50% from baseline was 32% among patients who used bleach bathing compared with 22% among controls (RR = 1.45; 95% CrI, 1-2.14).

From an analysis of seven studies, the researchers found, with low certainty, that bleach may slightly decrease the chance of having a positive Staphylococcus aureus skin culture (RR = 0.89; 95% CI, 0.73-1.09).

Another analysis of seven studies showed bleach-based interventions appeared to cause few if any adverse events (RR = 0.98; 95% CI, 0.6-1.61). Most reported adverse events were mild, including dry skin and irritation. One patient who used bleach bathing was hospitalized, which the study researchers attributed to incompliance and the development of a skin infection.

The researchers noted that findings for itch, sleep quality, risk for AD flares and quality of life were not clearly different between groups, with analyses showing low to very low certainty.

“Our findings are consistent with mechanistic data showing that bleach baths exert beneficial anti-inflammatory effects,” Bakaa and colleagues wrote. “The relation between this and the microbiome, however, is less clear.”

Among limitations, the researchers noted high levels of heterogeneity among the studies and small population sizes.

“This review, synthesizing the totality of evidence to date and with no more trials registered, provides moderate quality evidence bleach baths two to three times per week probably improves AD severity by a modest amount and possibly promotes little to no adverse events,” Bakaa and colleagues concluded. “These findings support patients, clinicians, researchers and policy makers in striving for optimal outcomes for patients with AD.”