Nasal and skin microbiomes are associated with disease severity in paediatric atopic dermatitis

Summary Background Alterations of the skin microbiome have been associated with atopic dermatitis (AD) and its severity. The nasal microbiome in relation to AD severity is less well studied. Objectives We aimed to characterize the nasal and skin microbiomes in children with AD in relation to disease severity. In addition, we explored the differences and correlations between the nasal and skin communities. Methods We characterized the microbial composition of 90 nasal and 108 lesional skin samples cross‐sectionally from patients with AD, using 16S‐rRNA sequencing. In addition, a quantitative polymerase chain reaction was performed for Staphylococcus aureus and Staphylococcus epidermidis on the skin samples, and AD severity was estimated using the self‐administered Eczema Area and Severity Index. Results We found an association between the microbial composition and AD severity in both the nose and skin samples (R2 = 2·6%; P = 0·017 and R2 = 7·0%; P = 0·004), strongly driven by staphylococci. However, other species also contributed, such as Moraxella in the nose. Skin lesions were positive for S. aureus in 50% of the children, and the presence and the load of S. aureus were not associated with AD severity. Although the nose and skin harbour distinct microbial communities (n = 48 paired samples; P < 0·001), we found that correlations exist between species in the nose and (other) species on the skin. Conclusions Our results indicate that both the nasal and the skin microbiomes are associated with AD severity in children and that, next to staphylococci, other species contribute to this association. What's already known about this topic? Changes in the skin microbiome have been associated with atopic dermatitis (AD) and its severity. Although the anterior nares could be an important reservoir for self‐contamination and bacterial spread from the nose to the skin or vice versa, research on the relation between the skin and nasal microbiome in AD is limited. What does this study add? Both the nasal and the skin microbiome are associated with the severity of AD in children. Next to staphylococci, other species contribute to the association between the microbiome and AD severity. Linked Comment: Clausen and Agner. Br J Dermatol 2019; 181:661–662. Respond to this article