The term angioedema refers to inflammation (edema) of the skin, mucosa, and submucosal tissues of the patient. In this clinical picture, the face, lips, tongue, larynx, extremities and practically any part of the body can be seen asymmetrically involved. It is associated with allergic conditions, but this is not always the case.
In the United States, approximately 100,000 patients present to emergency departments annually with clinical signs of angioedema; in many cases, associated with an allergic-type disorder. The World Allergy Organization estimates that 20% of the world’s population suffers from hives or angioedema at some point in their life.
Angioedema that does not involve the respiratory system is usually uncomfortable, but relatively harmless. However, if airway blockages occur, the patient’s life can be in serious danger. If you want to know everything about this complex and interesting clinical entity, keep reading.
What is angioedema and what are its types?
As we have said, angioedema is the swelling of the most extensive areas of the subcutaneous tissue, which usually affects the face and sometimes the throat. It is a reaction similar to hives (only more internalized) and often occurs alongside it.
The mechanism that activates angioedema is related to histamine or bradykinin. Histamine is an imidazole amine involved in allergic responses that, in this clinical picture, are caused by insect bites, drugs, foods, and other potential allergens.
On the other hand, bradykinin is a physiological peptide that causes vasodilation. In the case of angioedema, the version related to this substance is usually hereditary, due to the consumption of certain drugs or lymphoproliferative diseases (abnormal production of lymphocytes).
There are various types of angioedema, depending on the causative agent and the physiological nature of the event. Thanks to the information provided by the Missouri Medicine portal and other sources, we tell you its peculiarities.
1. Acute allergic angioedema
In this case, angioedema occurs directly and acutely by the activation of mast cells, specialized cells of the immune system. When immunoglobulin E (IgE) antibodies – membrane receptors on these cells – bind to an allergenic substance, the mast cell releases mediators of the allergic response, such as histamine.
The histamine released in the dermis of the skin causes vasodilation and extravasation of the intravascular fluid, which favors the formation of the edema itself. This reaction is very similar to that of urticaria, but in the latter case the immune response is more superficial and occurs near the pain receptors, so it manifests itself with itching.
As you can see, we are describing a typical allergic reaction. In this case, angioedema usually appears together with hives within 1 to 2 hours of exposure.
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