Histamine-mediated angioedema

Histamine-mediated angioedema

Histamine-mediated wheals in a patient with urticaria

Angioedema is frequently seen in association with urticaria (hives) or allergic reactions. Very typically, the swelling is accompanied by the development of wheals and pruritus (itching). For more information, see www.urtikaria.net).

During an allergic reaction, the body releases a mediator known as histamine. Among its many actions, histamine acts to temporarily increase the permeability of the vascular walls, allowing increased amounts of fluid to escape from the blood vessels and enter the surrounding tissues. This results in swelling. Histamine also causes dilatation (widening) of the blood vessels, increasing blood flow. This produces erythema, or redness, of the skin. In Allergy-related angioedema, histamine is released as a result of exposure to substances one is allergic to (allergens).Angioedema in patients with urticaria is also mediated by histamine, but the release of histamine ist not caused by allergens. The most common causes of angioedema in patients with chronic spontaneous urticaria are infections, intolerance reactions (often due to medications such as aspirin or similar analgesics), and autoreactivity (pathological reaction of body against itself.Histamine-mediated angioedema normally responds well to treatment with  antihistamines, corticosteroids (“cortisone”) or adrenalin. Further information about histamine-mediated swellings can be found at www.urtikaria.net or www.allergie-centrum-charite.de.