DPP4 and urticaria: Angiotensin-converting enzyme inhibitors and dipeptidyl peptidase-4 inhibitors should not be used concurrently because dipeptidyl peptidase-4, like an angiotensin-converting enzyme, is a critical enzyme in the breakdown of bradykinin-utilization of liquid steroids in individuals with severe angioedema and urticaria combined with severe dysphagia due to anaphylaxis.