Potential safety concerns with DPP-4 inhibitors include post-marketing reports of hypersensitivity reactions, including anaphylaxis, angioedema, rash, urticaria, and exfoliative skin conditions such as Stevens–Johnson syndrome.76 It is speculated that these conditions may result from the blockade of GIP degradation, as well as that of other peptides, such as the glucagon secretin family hormones, pancreatic polypeptide proteins, neuropeptides, and chemokines. Here, DPP4 is linked to urticaria.