Dipeptidyl peptidase‐4 inhibitor‐associated bullous pemphigoid in a patient with acquired reactive perforating collagenosis

Bullous pemphigoid ( BP ) is a common autoimmune blistering disorder with unknown etiology. Recently, increasing numbers of BP cases which developed under the medication with dipeptidyl peptidase‐4 inhibitors ( DPP 4i), widely used antihyperglycemic drugs, have been reported in published works. Here, we report a case of DPP 4i (teneligliptin)‐associated BP that developed in a 70‐year‐old Japanese man. Interestingly, the patient had acquired reactive perforating collagenosis ( ARPC ), which is also known to be associated with the onset of BP . In the present case, clinical, histopathological and immunological findings suggested that DPP 4i rather than ARPC was associated with the onset of BP .