Angioedema is a transient and self limiting process, involving the subcutaneous and submucosal tissues. Patients often present with localized skin swelling (urticaria). The swelling can also occur in other organs and systems, such as the upper respiratory tract, gastrointestinal tracts, etc. The swelling is due to increased vascular permeability (extravascular leakage) of fluid into the interstitial tissues of these areas.
Angioedema often has an acute onset, lasting hours to days, and in many circumenstances, they recur and become chronic. The symptoms are troublesome, sometimes disabling, and rarely can be life-threatening. Extravascular leakage is mediated by histamine or bradykinin. While histamine mediated angioedema is responsive to antihistamine or steroid therapy, bradykinin mediated angioedema is not= triggered by allergies, therefore these remedies are often ineffective.
Hereditary angioedema (HAE) is a rare genetic condition. It is an inherited prototype of bradykinin-mediated angioedema. HAE is due to genetic variations that result in complement 1 esterase inhibitor (C1-INH) deficiency or dysfunction. Lacking of this critial regulating protein and/or its fucntion leads to bradykinin accumulation and angioedema. Diagnosis relies on combination of various factors, such as clinical presentation, family history, C1INH assays (protein levels and function), C4 , c1q, and testing for known genetic variants that are associated with HAE. Bradykinin is the principal mediator in the pathophysiology of HAE. Higher than normal concentration of bradykinin is associated with HAE. Measruement of bradykinin may assist in the differential diagnosis of HAE and patient managment. Please refer Resources Page for more information.