Urticaria can be frustrating for patients and physicians alike. Its triggers may be medications, food allergies, insect stings, or physical stimuli and are often difficult to determine, especially when the urticaria has become chronic. In this article, Dr Varadarajulu gives an overview of both acute and chronic urticaria and the angioedema that accompanies it in about 40% of patients. She also outlines an approach to help evaluate and manage these common conditions.