**Pseudoangioedema**

Sevgi Akarsu and Ecem Canturk

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/67850

#### **Abstract**

Angioedema is a rapid, localized and temporary subcutaneous edema, which targets the lips, eyelids, gastrointestinal and respiratory mucosa resulting in abdominal pain, asthma and even serious life‐threatening conditions like airway obstruction. There are several other disorders such as allergic contact dermatitis, drug rash with eosinophilia and systemic symptoms (DRESS), superior vena cava syndrome (SVCS), orofacial granu‐ lomatosis and so on, which manifest with subcutaneous swelling and masquerade as angioedema and are known as 'pseudoangioedema' in the literature. Knowledge of pseu‐ doangioedema for healthcare professionals is crucial to avoid potentially serious results of misdiagnosis such as further investigations, unnecessary applications and delayed diagnosis. We aim to discuss differential diagnosis of angioedema and help physicians recognize the typical features of angioedema and its differential diagnosis in this chapter.

**Keywords:** angioedema, pseudoangioedema, angioedematous, pseudoangioedematous, angioedema differential diagnosis, angioedema mimickers, swellings mimic angioedema, masquerading as angioedema, angioedema similar disease

#### **1. Introduction**

Angioedema is defined as a rapid, localized and temporary swelling of the skin and/or mucous membranes caused by increased endothelial permeability and extravasation of intravascu‐ lar fluid into the interstitial tissues. It has predilection sites, including the lips, tongue, eye‐ lids, gastrointestinal and respiratory mucosa [1, 2]. Angioedema represents one of the most common airway emergencies, so quick diagnosis and intervention mean the life of a patient. Although coexistence with urticaria is frequent (50%), angioedema without urticaria is defined

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as a distinct disease. Angioedema without urticaria, called Quincke's edema/angioneurotic edema, is classified into two main categories: hereditary and acquired angioedema [1–3]. Hereditary angioedema is a severe and rare form caused by genetic mutations in the comple‐ ment C1 inhibitor, factor XII gene or unknown etiology. Four types of acquired angioedema are identified: idiopathic histaminergic angioedema, idiopathic non‐histaminergic angioedema, acquired angioedema related to angiotensin‐converting enzyme inhibitors and acquired angioedema with C1 inhibitor deficiency [3]. Several disorders can cause subcutaneous swell‐ ing and are often misdiagnosed as angioedema. These conditions which mimic angioedema are known as 'pseudoangioedema' in the literature [2, 4]. Misdiagnosis may lead to life‐threat‐ ening results because of ineffective management of these serious medical conditions. There are some clues help distinguish angioedema from other causes of swelling. Angioedema is characterized by asymetric and transient swelling, typically lasting 24–48 hours. It is essential to be aware of angioedema mimickers for healthcare professionals in both the emergency and outpatient setting [1, 2, 4].

## **2. Research design**

This chapter based on a literature search in Pubmed using the keywords 'angioedema', 'pseudo‐ angioedema', 'angioedematous', 'pseudoangioedematous', 'angioedema differential diagnosis', 'angioedema mimickers', 'swellings mimic angioedema', 'masquerading as angioedema' and 'angioedema similar disease'. Case reports, clinical trials, cohort studies, systematic reviews and meta‐analyses associated with these keywords published up until now were evaluated.
