Does the Skin Microbiome and Host Genetics Affect Atopic Dermatitis?

We know that the body’s microbiome, that is the bacteria, viruses, and fungi that inhabit the human body, can affect the host cells and immunity. Therefore, understanding the interplay between host cells and resident bacteria is important to recognize how the microbiome interacts with dermatological conditions. This knowledge helps to further refine how we approach treatment strategies in conditions such as atopic dermatitis.

A recent study looked at whether the skin microbiome in patients with atopic dermatitis (AD) was associated with disease severity and filaggrin gene mutations. For patients with AD, the microbiome is heavily populated by Staphylococcus aureus (S aureus) and is less diverse than is seen in healthy skin. Filaggrin gene (FLG) mutations are the strongest identified genetic risk factor for the development of AD. A total of 56 patients with AD and 45 healthy controls were included in the study.

The results showed that there were FLG mutations present in 17 patients with AD. Using skin and nose swabs, the study showed that there were differences in the microbiome composition between AD and controls, both for skin and nose samples, and there were also differences in composition between AD lesional and nonlesional skin. A difference in the microbiome composition between patients with AD who had FLG mutations and patients with AD without FLG mutations was found for nonlesional skin in those patients. In addition, they found decreased diversity in the microbiome composition of lesional skin compared with nonlesional skin. The more severe the AD, the less diverse the microbiome. These alterations in the diversity show the global effects of AD on the microbiome in patients.

The study also was able to make an association between FLG mutations and the microbiome composition of AD nonlesional skin. This link is more evidence of a possible association between the skin microbiome and host genetics.

The authors conclude that this study confirms that the skin microbiome is significantly different in patients with AD. They state that more research into the functional mechanisms of the microbiome will help us understand if microbes can cause or alter skin diseases like AD.