Unlocking Eczema Solutions: How DNA Testing for Good Bacteria Can Help Diagnose Your Condition

New Diagnostic Method for Childhood Eczema

Understanding the Skin Microbiome

Scientists have introduced an innovative approach to diagnose childhood eczema by examining the various bacteria present on the skin. The skin is home to a diverse range of microorganisms, including viruses, fungi, mites, and bacteria, collectively referred to as the skin microbiome. While this may seem unsettling, these microorganisms play a crucial role in supporting the immune system’s ability to fend off infections.

The composition of bacteria on an individual’s skin varies significantly from person to person. This variation is influenced by multiple factors, including environment, age, sex, diet, geographic location, clothing choices, occupation, cosmetic products, and antibiotic usage. Consequently, the skin can be likened to an ecosystem, containing numerous habitats with distinct microorganisms.

The Impact of Microbiome Disruption

Disruptions to either the host or the microbiome may lead to infections and skin disorders. Atopic dermatitis, commonly known as eczema, is a prevalent inflammatory skin condition in children, affecting approximately 5-20% of infants globally. Although the exact causes of eczema remain unclear, the skin microbiome is believed to play a significant role.

Research indicates that low diversity of skin bacteria correlates with increased disease severity. Specifically, the proliferation of the Gram-positive bacterium Staphylococcus aureus has been linked to skin flare-ups and heightened symptom severity.

Innovative Research on Eczema Diagnostics

Study Overview

A recent study conducted in China, published in mSystems, aimed to determine whether alterations in the skin microbiome could lead to a non-invasive diagnostic tool for eczema. The researchers compared the skin microbiomes of children with eczema to those of healthy controls. The participants, aged three to twelve, were selected from Beijing, Qingdao, and Denver.

Samples were collected from both lesion and non-lesion sites, typically on the forearms or legs, and compared to samples from healthy children. The bacterial types in each sample were identified through DNA sequencing.

Findings on Bacterial Composition

The researchers investigated various factors affecting the skin microbiome’s composition and discovered that geographical location and the presence of eczema had the most significant impact on bacterial colonization. They created a diagnostic model tailored to each city, taking into account the bacteria specific to each region. The diagnostic accuracy was found to be 91.3% in Beijing, 89.4% in Qingdao, and 79.2% in Denver.

When these models were tested in different cities, accuracy decreased, prompting the researchers to explore the possibility of developing a generalized model for diagnosing eczema. By combining data from healthy and eczema samples across all three cities, they identified a list of twenty-five bacterial types that effectively distinguished between healthy and eczema-affected samples, leading to the creation of the Microbial Indicator of Skin Health (MiSH) with a diagnostic accuracy of 86.4%.

Identifying Suboptimal Health States

Using their diagnostic tool, the team identified a subset of children who exhibited no eczema symptoms but had a skin microbiome indicative of a disease state. This group was categorized as being in a “suboptimal health state,” suggesting a potential risk for developing eczema in the future.

Tracking Treatment Responses

The researchers also sought to determine whether the skin microbiome would change post-treatment and if MiSH could monitor these changes. In a treatment phase, children in Beijing received corticosteroids for four weeks, with subsequent skin samples taken. Results indicated that the skin microbiome reverted to a healthy state following treatment.

Furthermore, the team was able to predict which patients would respond favorably to treatment based on their skin’s bacterial composition.

Considerations and Future Directions

While this new diagnostic tool for eczema represents a significant advancement, several limitations must be acknowledged. The MiSH requires further validation due to the small sample sizes used in this study. Testing the diagnostic tool in a more diverse population of children would also enhance its applicability. Additionally, it is important to recognize that DNA sequencing can identify bacterial populations but cannot differentiate between living and dead bacteria.

References

1. Grice, E. A. & Segre, J. A. The skin microbiome. Nature Reviews Microbiology 9, 244 (2011).
2. Salava, A. & Lauerma, A. Role of the skin microbiome in atopic dermatitis. Clinical and translational allergy 4, 33 (2014).
3. Williams, M. R. & Gallo, R. L. The role of the skin microbiome in atopic dermatitis. Current allergy and asthma reports 15, 65 (2015).
4. Grice, E. A. in Seminars in cutaneous medicine and surgery. 98 (NIH Public Access).
5. Fyhrquist, N., Salava, A., Auvinen, P. & Lauerma, A. Skin biomes. Current allergy and asthma reports 16, 40 (2016).
6. Weyrich, L. S., Dixit, S., Farrer, A. G., Cooper, A. J. & Cooper, A. J. The skin microbiome: associations between altered microbial communities and disease. Australasian Journal of Dermatology 56, 268-274 (2015).
7. Sun, Z. et al. A Microbiome-Based Index for Assessing Skin Health and Treatment Effects for Atopic Dermatitis in Children. mSystems 4, e00293-00219 (2019).