The microbiome and atopic eczema: More than skin deep.

Discoveries in the defective molecular composition of the epidermal barrier, such as the epidermal protein filaggrin, in those with atopic eczema (or atopic dermatitis [AD]) have proved crucial in understanding this disease, but its aetiology remains to be fully elucidated. The epidermal barrier is just one interface between the microbial world and our immune system. Recent advances in molecular technology have demonstrated for the first time the true scale of the normal human microbiome and changes seen in disease states. In this review article we discuss the role of the human microbiome in the aetiology and maintenance of AD. The role of Staphylococcus aureus within the skin microbiome is examined, in addition to the role of other bacteria and fungi, identified using novel culture-independent methods. The significant contribution of the gut microbiome and its manipulation via probiotic use is also reviewed. We emphasise that the microbiome of separate systems, including the gut, has a significant role to play in the manifestation of this cutaneous disorder. To date, there has been a lack of studies investigating whether changes to the lung microbiome may play a role in AD. An early interaction between the microbiome and immune system via multiple routes (skin-gut-lung) could feasibly affect the risk of a subsequent development of atopic diseases. When making management decisions for AD patients, clinicians must be mindful of the role of the microbiome.