“…Higher prevalence of BP may be due to the increasing mean age of the population, more frequent use of provoking drugs, such as loop diuretics, penicillin or PD-1/PD-L1 inhibitors, increased incidence of associated diseases (e.g., neurological diseases or hematologic malignancies), and recognition of atypical types of the disease [ 3 , 4 , 5 , 6 , 7 , 8 ]. However, some studies showed a higher prevalence of diabetes mellitus and a higher number of antidiabetic dipeptidyl peptidase 4 inhibitor (DPP4i) taking patients among BP patients [ 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 ]. An increasing number of studies showed association of DPP4i and bullous pemphigoid, but the exact mechanism of this association remains unclear [ 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 ].…”