Urticaria (hives) are a very common eruption. They are both allergic and nonallergic causes. Hives are classified as acute and chronic. Hives lasting longer than 6 weeks are arbitrarily classified as chronic urticaria. Acute urticaria is often caused by exposure to medication or foods. The cause however in many cases is never determined. Angioedema is a hive-like reaction that occurs deeper and the skin. Angioedema may be caused by medications such as ACE inhibitors (lisinopril). There are rare hereditary forms of angioedema. Angioedema may be severe with airway obstruction which can be fatal.


Hives. An extensive case showing swelling with a uniform and poly-cyclic pattern.


Angioedema is a type of hive that occurs deeper in the skin. These can be found on any skin surface but are commonly found on the lips and palms.