雙基胜肽酶抑制劑（dipeptidyl peptidase 4 inhibitor, DDP-4i）是臨床上廣泛使用的口服血糖藥物，具有很高的安全性。然而其仍然可能發生罕見且嚴重的藥物不良反應。本案例是一位76歲男性病人，因為皮膚反覆水泡而入院，經進一步之詳細藥史檢視後，高度懷疑為藥物相關類天疱瘡（drug-related bullous pemphigoid），經抗基底膜抗體（anti-basement membrane zone antibody, Anti-BMZ Ab）檢驗仍然無法確定診斷。進一步進行皮膚切片（skin biopsy）與病理免疫螢光檢查（immunofluorescence）報告後，與皮膚科及病理科醫師討論完後才確定診斷為類天疱瘡，並依據症狀給予用藥治療後改善。臨床上許多的疾病，診斷上賴於身體評估或單純血液檢驗是不足的，經常需要進一步釐清用藥史甚至進行組織切片，並與多專科醫師共同討論，才可以得到正確的診斷給予及時的治療。

Dipeptidyl Peptidase 4 Inhibitor (DDP-4i) is a clinically widely used oral hypoglycemia agents with high safety. However, rare and serious adverse drug reactions can still occur. This case is a 76-year-old male patient who was admitted to the hospital for recurring bullous. After a detailed review of his medication history, drug-related pemphigoid (bullous pemphigoid) was highly suspected. We checked several times of serum antibody, a definitive diagnosis could not be established. After the skin biopsy and direct immunofluorescence (DIF), discussed with the dermatologist and pathologist, bullous pemphigoid was diagnosed. The patient's condition improved with appropriate treatment based on the symptoms. For many clinical diseases, the diagnosis of many diseases often requires more than physical assessment or simple blood tests. It often involves clarifying medication history or tissue biopsy, and collaborating with multiple specialists to reach a correct diagnosis and provide timely treatment.