How does hereditary angioedema differ from “normal” angioedema?
Angioedema is a symptom that occurs in the context of two different diseases. The strict differentiation of the two clinical pictures is important because the development and also the treatment of the diseases are clearly different. While hereditary angioedema is a hereditary disease caused by a lack of inactivation or excessive activation of the complement system, “normal” angioedema, also known as Quincke’s edema, often occurs in the context of hives (urticaria).
It can be a concomitant symptom of urticaria, but it can also occur in isolation. The angioedema that occurs in the context of urticaria is histamine-mediated. They therefore occur in the context of an allergic reaction.
The body reacts allergic and an increased histamine release occurs. Histamine leads to an increased permeability of the blood vessels (vascular permeability) and there is an increased flow of fluid from the vessels into the tissue.Both forms of angioedema therefore have in common that there is increased leakage of vascular fluid into the tissue. This results in swelling of the affected areas.
However, the tissue hormone that triggers the swelling differs: histamine in “normal” angioedema versus bradykinin in hereditary angioedema. While hereditary angioedema often causes symptoms for the first time before the age of 20, “normal” angioedema often manifests itself only in adulthood. In “normal” angioedema, the histamine effect not only causes swelling but also redness and itching in the swollen areas.
In hereditary angioedema, on the other hand, the swelling is not reddened but skin-colored and itching is rare. The cause of “normal” angioedema can be infections or medication. In many cases, however, the cause remains unexplained.
In “normal” angioedema, in most cases no pathological laboratory values are found, while in the hereditary form certain values are conspicuous. While hereditary angioedema occurs in the face, but often also in the gastrointestinal tract, “normal” angioedema usually only affects the facial area (especially the mouth and eye area). In both forms of the disease there is a risk of swelling of the airways, the laryngeal edema.
This is acutely life-threatening and requires immediate emergency treatment. However, the type of emergency therapy – as well as the standard therapy – differs between the two forms. The “normal” angioedema responds well to therapy with antihistamines or steroids/corticoids, such as prednisolone, and adrenaline as part of emergency therapy. In hereditary angioedema, on the other hand, these drugs are ineffective and special drugs must be used.
