The skin microbiome and atopic dermatitis: a review

Abstract

Atopic dermatitis is a common chronic inflammatory skin disease that may be accompanied by food allergy, allergic rhinitis or asthma. The pathogenesis of atopic dermatitis is complex and based on interaction between an impaired epidermal barrier, immune dysregulation of both innate and adaptive immunity and the skin microbiome. The skin microbiome plays an essential role in the development and, consequently, normal functioning of the skin immune system. The term microbiome is used to describe the collection of microorganisms and its genomic elements in a particular ecological niche. These microbial communities comprise a variety of microorganisms, including eukaryotes, archaea, bacteria, viruses and skin mites. The bacterial community of the skin is conditionally divided into two groups. Resident bacteria belong to a group of microorganisms that live relatively permanently on the surface of the skin. They are often referred to as commensal bacteria, which are necessary for the normal development and maintenance of the bodys immune defenses. In turn, transient microorganisms that temporarily inhabit the surface of the skin enter it from the environment and persist from several hours to several days. Under normal conditions, with proper hygiene and normal integrity of the skin barrier, resident and transient microbes are not pathogenic. Thus, cutaneous dysbiosis can lead to immune system overactivity as well as inflammatory skin conditions. It has been shown that the relationships between microbes within the skin surface play an important role in the development of atopic dermatitis. Moreover, exacerbations of the atopic dermatitis are associated not only with the loss of microbial diversity but also with the predominance of Staphylococcus aureus. Further skin microbiome studies and thus understanding of its role in atopic dermatitis could provide an effective therapeutic approach to restore well-balanced skin microbiome.