Higher inflammatory skin protein levels and changes of the skin microbiome precede and characterize childhood atopic dermatitis

Atopic dermatitis (AD), also known as atopic eczema, is the most common inflammatory skin disease in children. However, we are currently unable to reliably predict if or when AD might occur during childhood. This study aimed to find changes of skin proteins and skin microbiome that happen before AD occurs and those that are typical of early childhood AD. The study also aimed to use the least invasive methods possible by using skin swabs and tape strips.

50 infants of parents with a history of AD were included in a clinical trial on early emollient (moisturiser) use for AD prevention.

13 of these infants developed AD until month 24 with children being an average age of 10 months when AD began. In these 13 children, levels of multiple important inflammatory skin proteins (IL-1Ra, TNFβ, IL-8, IL-18, IL-22, CCL2, TARC, TSLP and VEGFa) increased even before AD occurred. Levels of some of these proteins (IL-1Ra, TNFβ and VEGFa) already increased shortly after birth. Further, these children displayed a delayed maturation and differentially composed skin microbiome prior to AD onset compared to children that never developed AD. When AD occurred, we found that levels of important skin proteins were again higher, and many healthy skin bacteria (i.e. multiple Streptococcus species) were reduced, whereas the potentially harmful Staphylococcus epidermidis was increased.

Our results tell us that higher inflammatory skin protein levels and changes of the skin microbiome happen before a child experiences AD and are typical of childhood AD when it occurs.