The Skin Microbiome and its Significance for Dermatologists

The skin is a physical and immunological barrier to the external environment. Its large surface area is colonized by diverse communities of microorganisms, including bacteria, viruses, fungi, and Demodex species mites. These microorganisms and their genetic material together create the skin microbiome. Physiologic and anatomic properties of skin sites create biogeographical habitats (dry, moist, and sebaceous) where distinct microbiota communities reside. Although, in general, the composition of these habitats is maintained from person to person, the skin microbiome of an individual also has unique microbial features. Dysbiosis occurs when the normal abundance, composition, or location of the microbiota is changed, most notably there is a decrease in flora diversity. Certain skin diseases, including atopic dermatitis, rosacea, and psoriasis are associated with cutaneous dysbiosis, and even disruption of the gut microbiota. Studies have shown that current treatments for these dermatologic conditions can alter/stabilize the skin microbiome, and there is emerging research detailing the impact of prebiotics, probiotics, and postbiotics on these conditions. Although clinical guidelines do not currently exist, clinical studies support the safety and possible benefits of using topical prebiotics and postbiotics and oral probiotics for a variety of skin conditions. Until such guidelines exist, utilizing carefully designed clinical studies to inform clinical practice is recommended.