Abstracts, JCMS, Vol. By clinical description it is a typical wheal and flare response characterized by blanchable, ery-thematous, and edematous cutaneous lesions. Urticarial lesions are usually tran-sient and infrequently persist longer than 24 to 48 hours. Often associated with urticaria is a deeper subcutaneous swelling called angioedema. A cause is rarely identified, hence the term chronic idiopathic urticaria.
Mast cells play a central role in the pathophysiology of urticaria.
When activated, mast cells release potent inflammatory mediators into the extracellular cutaneous compartment. The stimulation of free nerve end-ings is responsible for the primary symptom of itching and burning. Mast cell mediators may be released by a number of different mechanisms. Immunologic activation may occur when IgE antibodies bound to the mast cell surface recep-tors are bridged by specific allergen. However, this is only the tip of the iceberg.