What does the research say about the skin microbiome?

The skin microbiome is the collective community of microorganisms—bacteria, fungi, and viruses—that live on the skin. It is not a single entity but a dynamic ecosystem. Research has examined its composition and function in relation to skin barrier integrity, inflammatory skin disease, and systemic conditions. The studies summarised here are registered clinical trials and observational protocols; they measure microbiome parameters as outcomes, but they do not establish that altering the microbiome prevents or treats any disease.

The work centres on the relationship between skin barrier function, cutaneous inflammation, and microbial communities. Several trials focus on the skin microbiome as a secondary or exploratory endpoint alongside clinical and biochemical markers.

Research Studies

Vernix caseosa retention and atopic dermatitis prevention in newborns

Vernix caseosa is a naturally occurring, white, creamy substance that covers the skin of newborns at birth and forms during the last trimester. A clinical trial is investigating whether retaining vernix caseosa on newborn skin can prevent atopic dermatitis (AD), also known as eczema. AD is a chronic inflammatory skin disease that usually begins in infancy and causes itching, discomfort, and sleep disturbance. It affects up to one in five children worldwide. Research has shown that genetic and environmental factors contribute to its development, especially those related to skin-barrier integrity and the skin microbiome during early life. Preventing AD before it starts—known as primary prevention—has become an important goal. This study is registered but results are not yet available [1].

Skin barrier restoration and microbiome change in older adults

A randomized, investigator-blinded, self-controlled pilot study is examining the physiologic response to topical moisturizers among older adults with dry skin. The overarching hypothesis is that skin barrier decline is an important source of chronic inflammation, and that skin barrier restoration with moisturizers can reduce serum biomarkers of inflammation. The primary objective is to determine the feasibility for a larger trial. Secondary objectives include determining the extent to which measures of serum inflammation, skin barrier function, and the skin microbiome change in response to moisturizers. Participants apply one of two topical moisturizers that are widely available. This study is ongoing; no results are reported in the registry entry [3].

Topical ivermectin and the skin microbiome in rosacea

A single-site, 16-week open-label study at the University of California, San Diego, is assessing the role of topical ivermectin 1% cream and its effect on protease and antimicrobial peptide expression and on the skin microbiome in rosacea. Investigators first measure serine protease activity, cathelicidin, and the skin microbiome of all subjects. All subjects then receive ivermectin topical cream and are instructed to apply it daily for 12 weeks. Participants return for monthly visits during which clinical symptoms of facial redness and number of facial papules are scored. The study is registered but results are not yet posted [4].

Biological profile of lymphedema: inflammatory and lymphatic markers

An observational, cross-sectional study aims to characterize the biological profile of primary and secondary lymphedema by investigating five interconnected biological domains: T helper 2 (Th2)-related inflammation, endothelial activation, metabolic dysfunction, lymphatic biology, and tissue fibrosis. Lymphedema is traditionally considered a disorder of impaired lymphatic drainage resulting in the accumulation of interstitial fluid. However, increasing evidence suggests that its development and progression involve chronic inflammation, endothelial dysfunction, metabolic alterations, abnormal lymphatic signaling, adipose tissue accumulation, and progressive tissue fibrosis. The skin microbiome is not a stated focus of this study, but the inflammatory and barrier-related pathways overlap with those examined in microbiome research. This study is registered; results are not yet available [2].

Summary of study designs and outcomes

Limitations and evidence gaps

All four studies are registered protocols; none report results in the evidence provided. The evidence does not include animal-only or in vitro studies, nor does it provide data on the efficacy of any intervention for altering the skin microbiome or treating disease. The studies measure microbiome parameters as exploratory or secondary outcomes, and their findings are not yet available. No conclusions can be drawn about causation or clinical benefit from these registered trials alone.

If you are reading this for personal health reasons

The materials and information described here are for laboratory research use only. We do not provide dosing, medical guidance, or recommendations for personal use. Anyone considering a compound or intervention for themselves should speak to a licensed clinician.

Sources

• [1] Retention of Vernix Caseosa in Newborns for Primary Prevention of Atopic Dermatitis — ClinicalTrials.gov
• [2] Biological Profile of Primary and Secondary Lymphedema: Inflammatory, Endothelial, Metabolic, Lymphatic, and Fibrotic Markers — ClinicalTrials.gov
• [3] Skin Barrier Function and Inflammation in Aging: The BIA Study — ClinicalTrials.gov
• [4] Evaluation of the Inhibitory Effects of Topical Ivermectin on Markers of Rosacea Specific Inflammation — ClinicalTrials.gov