TLR7 and viral infectious disease: In recent years, research on psoriasis pathogenesis has largely expanded our knowledge of the skin microbiome; one of the proposed mechanisms is that antimicrobial peptides (AMPs) secreted by keratinocytes in response to bacterial/viral infections or injury can bind to self‐DNA/RNA fragments released from affected keratinocytes to stimulate pDCs through TLR7/8,27 then release high amounts of TNF‐α, IL‐12 and IL‐23.28