We searched the published literature from PubMed and ClinicalTrial.gov with the search terms including ‘IL-17,’ ‘psoriasis,’ ‘atopic dermatitis,’ ‘hidradenitis suppurativa,’ ‘alopecia areata,’ ‘pityriasis rubra pilaris,’ ‘pemphigus,’ ‘systemic sclerosis,’ ‘secukinumab,’ ‘ixekizumab,’ ‘brodalumab,’ ‘bimekizumab,’ ‘ustekinumab,’ ‘tildrakizumab,’ ‘guselkumab,’ and ‘risankizumab’. This evidence concerns the gene IL17A and psoriasis.