Microbiome and Eczema​

 

Atopic dermatitis (AD), commonly known as eczema, is a prevalent and chronic inflammatory skin disease affecting millions of people worldwide. While the exact causes and mechanisms behind AD remain elusive, emerging research points to the microbiome as a significant contributor to disease development and progression.

 

The Microbiome and AD

The microbiome refers to the diverse community of microorganisms, including bacteria, fungi, and viruses, that reside on and within the human body. These microscopic inhabitants play a crucial role in maintaining overall health, particularly in supporting immune function and contributing to the development and maturation of the immune system. In the context of AD, mounting evidence suggests that individuals with this skin condition have a disturbed and less diverse microbial composition compared to those without AD. The lack of microbial diversity can lead to an imbalance in the skin and gut microbiota, potentially contributing to the onset and progression of the disease.

 

The Hygiene Hypothesis: Explaining the Microbiome-AD Connection

The hygiene hypothesis offers a compelling explanation for the relationship between the microbiome and AD. This hypothesis proposes that modern-day sanitization and reduced microbial exposure in early life result in inadequate immune priming. In simpler terms, our cleaner and more sanitized living environments may lead to underdeveloped immune systems in children, making them more susceptible to allergic conditions like AD.

In the early stages of life, a child's microbiota plays a protective role in priming and training the immune system, preventing it from becoming overly sensitive to allergens. This protective influence helps maintain a balanced and healthy immune response, reducing the risk of immune-related conditions like AD. Conversely, an imbalance or poor development of the microbiome may disrupt the immune system's response, leaving children more prone to immune disorders like AD.

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The Complex Interplay: Barrier Defects and Microbial Composition

The relationship between AD and the microbiome is multifaceted. It remains unclear whether changes in the microbial composition observed in AD patients are a consequence of skin barrier defects or if they are the cause of barrier dysfunction and inflammation. Some researchers speculate that compromised skin barriers in individuals with AD may create an environment conducive to an imbalanced microbiome, while others propose that alterations in the microbiome could directly contribute to skin barrier disruption and immune dysregulation.

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Potential Therapeutic Approaches: Modulating the Microbiome

The intriguing concept of modulating the skin and gut microbiome as a preventive and therapeutic measure for AD has gained attention. This approach involves using moisturizers containing nonpathogenic biomass or supplementing with probiotics during early childhood to promote a more diverse and balanced microbiota. By doing so, it is hypothesized that the immune system could receive better priming, potentially reducing the risk of allergic conditions like AD. However, despite the promise of such interventions, the evidence supporting their efficacy is currently limited. 

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The connection between the microbiome and AD has emerged as an exciting area of research, shedding light on the complex interplay between our microbial inhabitants and immune system function. Disturbances in the skin and gut microbiota have been implicated in AD development and atopic march, highlighting the importance of maintaining a diverse and balanced microbial community.

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Resources:​

• NIH 2019