The skin contains a diverse microbial ecosystem, which is seeded at birth, but evolves until a person reaches sexual maturity.
The skin is a largely dry and nutrient-poor environment, but some microbes such as Staphylococcus epidermidis and Cutibacterium acnes are able to survive. These skin residents communicate with host cells and help to defend against infection and injury2.
Turf wars lead to disease
The bacterium Staphylococcus aureus is associated with atopic dermatitis, a form of eczema common in children that can give rise to other allergies later in life. Several beneficial species of Staphylococcus normally protect against S. aureus, but genetics, and possibly environmental and lifestyle factors, can mean this balance of power is disturbed in some individuals, making them susceptible to the condition.