Currently, treatment of psoriasis involves topical medicines (corticosteroids, vitamin D analogs and acitretin), systemic drugs (methotrexate, dexamethasone and cyclosporine), phototherapy (UVA and UVB), and biological medicines (TNF-α antagonists, Janus kinase inhibitors, anti-IL-23 agents and anti-IL-17 agents) (Greb et al., 2016). This evidence concerns the gene IL17A and psoriasis.