Angioedema

Definition

Angioedema is a well-circumscribed, nonpitting swelling of the subcutaneous tissues of the skin and mucosa, which is typically nonpruritic. Sites of involvement include eyelids, lips, tongue, larynx, palms, soles, genitalia, and gastrointestinal tract. The condition results from the activity of inflammatory mediators that cause dilation and enhanced permeability of venules and capillaries. Sources of these inflammatory mediators include:

• Increased activity of the kinin pathway

• Abnormalities of complement metabolism

• Activation of mast cells in the dermis

The latter is typically associated with urticaria and pruritis. Angioedema may be distinguished clinically from other types of edema (e.g., congestive heart failure, hypoalbuminemia) by the rapidity of onset (minutes to hours) and by a distribution that is asymmetric and not localized to dependent areas of the body.

Both acquired and inherited forms of the illness exist. Acquired angioedema (AAE) may be acute or chronic (longer than 6 weeks in duration) whereas hereditary angioedema (HAE) is typically chronic and recurrent. Acute AAE is reported to occur in approximately 10% to 20% of the population, while HAE is reported to occur in approximately 0.01% of the population. However, the frequency of angioedema is likely higher than reported because of the self-limited nature of most attacks. Read the rest of this entry »

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