The Skin Microbiome & Eczema: How Tiny Organisms Shape Our Skin Health

When it comes to eczema, what you can’t see on the skin may be just as important as what you can. Scientists have been diving deep into the world of the skin microbiome—the trillions of bacteria and microbes living on our skin—to understand how they influence the onset and severity of eczema. One bacterium keeps stealing the spotlight: Staphylococcus aureus (S. aureus).

The Skin Microbiome and Eczema

Research has revealed that people with eczema have a disrupted microbiome, often dominated by S. aureus. This shift plays a key role in worsening the condition. By contrast, healthy skin thrives on diversity—a mix of beneficial bacteria that help strengthen the skin barrier and regulate immune responses.

Interestingly, even age seems to matter. Young children with eczema have more diverse microbiomes than teenagers or adults, suggesting that maintaining bacterial variety is linked to better skin health.

And it may start from birth: infants with S. aureus colonization early on were more likely to develop eczema later in childhood.

When Bacteria Talk to the Immune System

S. aureus doesn’t just sit on the skin—it digs deeper. Using enzymes called proteases, it breaks through the skin barrier, triggering immune messengers (interleukins like IL-4 and IL-13) that lead to redness, swelling, and itching.

Fortunately, treatments that repair the skin barrier, such as moisturizers or advanced biologics like dupilumab, can restore balance. These not only reduce inflammation but also increase microbial diversity, helping healthy bacteria flourish again.

The Power of Microbial Balance

Healthy skin bacteria don’t just coexist—they fight back. Strains like S. epidermidis and S. hominis produce natural compounds that block S. aureus from causing harm. In fact, babies with more of these “friendly” bacteria were less likely to develop eczema later on.

This natural cross-talk has inspired researchers to explore therapies that add beneficial microbes back to the skin—like probiotics, bacterial transplants, or even lotions infused with commensal bacteria.

New Frontiers in Treatment

So far, traditional methods like antibiotics and bleach baths haven’t offered long-term solutions, since they wipe out good bacteria along with the bad. The new frontier is bacteriotherapy: purposefully adding protective bacteria or their products to restore balance.

Early clinical trials are promising. For example, applying S. hominis A9—a bacteria naturally found on healthy skin—helped reduce S. aureus levels and inflammation in both mice and humans. While these studies are still small, the potential for targeted microbiome therapies is enormous.

Key Takeaways

• Microbiome diversity = healthy skin. A wide variety of bacteria supports the skin barrier and immune system.

• S. aureus is the main culprit. Its overgrowth is linked to eczema flares and severity.

• Barrier repair and biologics help. Treatments that restore skin function also promote healthier bacterial balance.

• Future therapies may be bacterial. From probiotics to bacteriotherapy, supporting “good” microbes could change the way we treat—and maybe even prevent—eczema.

Final Thoughts: The skin is more than just a protective covering—it’s an ecosystem. By learning how to nurture that ecosystem, scientists hope to open up new possibilities for living well with eczema.