A case of type 2 diabetes mellitus with psoriasis vulgaris effectively treated with liraglutide

We herein report a 72-year-old woman who had type 2 diabetes mellitus for 23 years. She received treatment with 1-mg glimepiride and 50-mg vildagliptin, and her glycated hemoglobin level was 11.9 %. She also had a 10-year history of psoriasis vulgaris, which was being treated with phototherapy and external medicine but was poorly controlled. She was admitted to the hospital for glycemic control, so we discontinued all her medicine and started her on 0.3 mg/day of liraglutide, which we later reduced to 0.3 mg/week. On day 9, her subjective symptoms ameliorated, and her Psoriasis Area and Severity Index score improved from 11.3 to 4.2. Psoriasis vulgaris is a chronic inflammatory disease, and recent reports have found that biological products that target cytokines such as TNF-α are effective as its therapy. GLP-1 inhibitors reportedly affect immune cells and participate in cytokine regulation. The ameliorating effect on psoriatic skin lesions in this case might be related to the GLP-1 inhibitor' s immunological mechanism.