In terms of its association with diabetes, there is increasing evidence of the positive effects of anti-diabetic drugs on psoriasis including glucagon-like peptide-1 (GLP-1) receptor agonists, dipeptidyl peptidase-4 (DPP-4) inhibitors, thiazolidinedione and biguanide [35,36,37,38,39,40]. Here, DPP4 is linked to psoriasis.