Angioedema is a deeper skin wheal. While in the case of hives, liquid emerges from the vessels just under the skin surface, the “leak” in angioedema is in the deeper skin layers.
Angioedema (angio = vessel, oedoema = water retention in the tissue) is characterized by:
- a sudden, severe swelling of the deeper layers of the skin
- sometimes pain, rarely itching
- frequent involvement of the mucous membranes – a regression that lasts up to 72 hours longer than with hives.
The resulting bump has a less prominent rim and is often indistinguishable from normal skin in color. Angioedema often occurs in the facial area, especially around the eyes and on the lips, and the hands and feet. Most of the swellings, in a broader sense are allergy-related and are mediated by the neurotransmitter histamine. But there are also other non-allergic and non-histamine-mediated causes of skin and mucosal swelling.