Effect of excimer light therapy on canine atopic dermatitis using 16S V1V3 microbiome sequencing.

Canine atopic dermatitis (AD) is a common chronic, allergic dermatitis and difficult to manage for various reasons (medical cost, owner compliance, response to treatment). To investigate the effects of 308nm excimer light therapy on canine AD using microbiome analysis, assessment of skin barrier function and clinical outcomes, this study employed Client-owned dogs with canine AD (n=10). The skin microbiome, skin barrier function (trans-epidermal water loss, TEWL; stratum corneum hydration, SC hydration) and clinical outcomes (Canine Atopic Dermatitis Extent and Severity Index version 4, CADESI-04; Pruritus Visual Analog Scale, PVAS) evaluated pre- and post-excimer light therapy in canine AD. The excimer light therapy increased the relative abundance of the phylum Actinobacteria and Cyanobacteria in canine AD. And the therapy decreased the relative abundance of Staphylococcus pseudintermedius in canine AD. In the assessment of skin barrier function, TEWL normalized with excimer light therapy, but SC hydration did not improve. Furthermore, the excimer light therapy improved CADESI-04 and PVAS in canine AD. These results suggest the excimer light therapy is new, effective treatment options for canine AD. This work provides that the skin microbiome analysis could be a strategy to confirm the therapeutic effect for canine AD.