How Tiny Microbes Shape Eczema
Imagine your skin not just as a smooth surface, but as a vast, varied landscape teeming with life.
It's home to a complex community of billions of bacteria, fungi, and viruses—a dynamic ecosystem known as the skin microbiome 9 . For most people, this invisible world exists in harmonious balance, quietly working to protect and maintain healthy skin. But for the millions of children and adults living with atopic dermatitis (AD), the most common form of eczema, this delicate balance is disrupted 2 .
This discovery is opening up new treatment approaches that aim to heal the skin by restoring its microbial balance.
The skin microbiome consists of all the microorganisms that live on our skin. More than 1,000 different bacterial species have been identified, along with various fungi and viruses 9 . This isn't a random collection of germs; it's a highly organized community where different microbes prefer specific skin environments.
In atopic dermatitis, the rich, diverse microbial community on the skin collapses into a state of dysbiosis—a scientific term for microbial imbalance 1 . This collapse has two key features: a dramatic loss of bacterial diversity, and the aggressive takeover by the harmful bacterium Staphylococcus aureus (S. aureus) 1 2 .
It releases toxins and proteases that damage the skin's protective outer layer, much like tearing down a protective wall 2 .
Its presence triggers alarm signals that activate immune cells, leading to the inflammation and itching characteristic of AD 9 .
It outcompetes beneficial bacteria for space and resources, further reducing microbial diversity 2 .
To understand how modern treatments affect the skin microbiome, researchers conducted a detailed cross-sectional analysis of 464 AD patients from the ProRaD cohort study 7 . This research aimed to decode the relationship between different therapeutic regimens and the microbial communities living on AD skin.
Patients with moderate AD who were receiving systemic immunomodulatory treatment showed a significantly lower relative abundance of S. aureus on their lesional skin compared to those receiving only topical treatments 7 .
Patients receiving dupilumab showed a reduced S. aureus abundance compared to those on conventional immunosuppressive treatments or systemic glucocorticoids 7 .
| Tool/Reagent | Primary Function | Application in Skin Microbiome Research |
|---|---|---|
| Sterilized Distilled Water | Non-disruptive sample collection | Collecting microorganisms from skin via gentle rinsing 4 |
| 0.22 µm PES Filters | Trapping microbial cells | Concentrating bacteria from rinse solutions for analysis 4 |
| DNA Extraction Kits | Isolating microbial genetic material | Preparing bacterial DNA for sequencing 4 |
| 16S rRNA Gene Sequencing | Identifying and quantifying bacteria | Determining microbial community composition 7 |
| Illumina MiSeq Platform | High-throughput sequencing | Processing multiple samples simultaneously to generate microbiome data 7 |
The growing understanding of the skin microbiome's role in AD has sparked exciting new approaches to treatment that focus on restoring balance rather than simply suppressing inflammation.
Researchers are exploring the use of beneficial bacteria as living medicines. In early-stage clinical trials, applying carefully selected strains of Roseomonas mucosa directly to the skin of AD patients led to decreased disease severity, reduced topical steroid needs, and a lower burden of S. aureus 9 .
Another promising approach involves Staphylococcus hominis A9, a commensal bacterium that produces antimicrobial molecules specifically targeting S. aureus. This bacterium is found in 21% of healthy people but only 1% of AD patients 9 .
For those cautious about applying live bacteria, researchers are developing alternatives:
The exploration of the skin microbiome has transformed our understanding of atopic dermatitis from a condition driven solely by internal immune dysfunction to one deeply intertwined with the invisible world of microbes living on our skin.
This perspective doesn't just offer new treatment options—it fundamentally changes our relationship with the microorganisms that call us home.
Rather than waging war against all microbes, the future of AD management appears to lie in fostering a healthy, diverse skin ecosystem.
By supporting the beneficial bacteria that naturally protect our skin, we can potentially break the cycle of inflammation and barrier damage that makes AD so persistent and distressing.