Topical ozone therapy restores microbiome diversity in atopic dermatitis (eczema)

Background

Atopic dermatitis - the most common form of eczema - is a chronic, relapsing inflammatory skin condition marked by intense itching and a disrupted skin barrier. Affected skin usually carries an altered microbial community, with an overgrowth of Staphylococcus aureus and a loss of the microbial diversity found on healthy skin. Researchers have become interested in whether treatments that rebalance this community, rather than simply suppressing inflammation, might help ease symptoms. This study examined topical ozone - delivered as ozone hydrotherapy followed by ozonated oil - as one such approach.

Study design

The trial enrolled 12 patients with moderate-to-severe atopic dermatitis, aged 6 to 28, who had roughly symmetrical lesions on both sides of the body. It used a split-body design: on each patient, one side received ozone hydrotherapy (ozone concentration around 3.0 mg/L) followed by ozonated oil twice daily, while the matching area on the opposite side received tap water and plain, non-ozonated oil as a control. Treatment ran for three days. The researchers scored disease severity with SCORAD and a modified Eczema Area and Severity Index (EASI), assessed inflammatory infiltration using reflectance confocal microscopy, and characterised the skin bacterial community through 16S ribosomal DNA sequencing alongside bacterial culture.

Findings

After three days, the ozone-treated sides showed a fall in SCORAD of roughly 22% relative to baseline, together with a reduction in inflammatory cells on confocal imaging. The proportion of Staphylococcus in lesions was correlated with disease severity; ozone treatment lowered Staphylococcus aureus, although this particular reduction did not reach statistical significance. At the same time, the proportion of Acinetobacter - a genus the authors associate with anti-inflammatory activity - rose significantly. Overall microbial diversity, which was lower in lesional than in non-lesional skin at the outset, increased on the treated sides.

What the authors concluded

The authors concluded that topical ozone therapy can rapidly relieve the symptoms of atopic dermatitis, including itching and inflammation, and that it appears to act in part by shifting the balance of the skin microbiome - reducing Staphylococcus while increasing Acinetobacter - and so helping to restore microbial diversity in affected skin.

Limitations of this study

This was a small, short study: only 12 patients were followed over three days, which limits how far the results can be generalised and leaves the durability of any effect untested. Skin microorganisms also vary considerably between individuals and with environmental conditions, so a larger sample would be needed to account for that variation. The authors further note that the 16S rDNA V4 sequencing method they used can under-represent some organisms (such as Staphylococcus epidermidis and Propionibacterium) and over-represent others (such as Staphylococcus aureus), which may affect the precise microbial proportions reported. The findings are best read as an early, exploratory signal rather than as definitive evidence.