Abstract
BACKGROUND: Patients with atopic dermatitis (AD) are prone to skin infections, with microbes such as Staphylococcus aureus suspected of contributing to pathogenesis. Bleach baths might improve AD by reducing skin microbial burden. OBJECTIVE: We sought to characterize the microbiota of lesional and nonlesional skin in young children with AD and control subjects and compare changes after treatment with a topical corticosteroid (TCS) alone or TCS + dilute bleach bath. METHODS: In a randomized, placebo-controlled, single-blinded clinical trial in 21 children with AD and 14 healthy children, lesional and nonlesional AD skin was examined at baseline and after 4-week treatment with TCS alone or TCS plus bleach bath. Microbial DNA was extracted for quantitative polymerase chain reaction of predominant genera and 16S rRNA sequencing. RESULTS: At baseline, densities of total bacteria and Staphylococcus, including Staphylococcus aureus, were significantly higher at the worst AD lesional site than nonlesional (P = .001) or control (P < .001) skin; bacterial communities on lesional and nonlesional AD skin significantly differed from each other (P = .04) and from control (P < .001). After TCS + bleach bath or TCS alone, bacterial compositions on lesional skin normalized (P < .0001), resembling nonlesional skin, with microbial diversity restored to control skin levels. LIMITATIONS: The 4-week time period and/or the twice-weekly baths may not have been sufficient for additional impact on the cutaneous microbiome. More detailed sequencing may allow better characterization of the distinguishing taxa with bleach bath treatment. CONCLUSIONS: Treatment with a TCS cream suffices to normalize the cutaneous microbiota on lesional AD; after treatment, bacterial communities on lesional skin resemble nonlesional skin but remain distinct from control.