Angioedema

Angioedema

Angioedema of the lips

Angioedema affecting the face

Severe angioedema of the face

Angioedema is a medical condition characterized by the rapid swelling of the dermis, subcutaneous tissue, mucosa, and submucosal tissues. It is similar to urticaria (hives), but angioedema occurs deeper in the skin. The swelling is often localized and can affect various parts of the body, including the face, lips, tongue, throat, and extremities.

Etiology

Angioedema can be classified into several types based on its etiology:

• Allergic Angioedema: This type is often associated with allergic reactions to foods, medications, insect stings, or other allergens. It is mediated by immunoglobulin E (IgE) and is often accompanied by urticaria.

• Hereditary Angioedema (HAE): A rare genetic disorder caused by a deficiency or dysfunction of the C1 inhibitor protein, leading to excessive production of bradykinin, a peptide that increases vascular permeability.

• Acquired Angioedema: Similar to hereditary angioedema but occurs later in life and is often associated with autoimmune diseases or lymphoproliferative disorders.

• Drug-Induced Angioedema: Commonly associated with the use of angiotensin-converting enzyme inhibitors (ACE inhibitors), which can increase bradykinin levels.

• Idiopathic Angioedema: When no specific cause can be identified.

Pathophysiology

The pathophysiology of angioedema involves the release of mediators that increase vascular permeability, leading to fluid leakage into the interstitial tissues. In allergic angioedema, histamine is the primary mediator, while in bradykinin-mediated angioedema (such as HAE), bradykinin is the key mediator.

Clinical Presentation

Patients with angioedema typically present with sudden onset of swelling in the affected areas. The swelling is usually non-pitting and can be painful or itchy. In severe cases, especially when the airway is involved, angioedema can be life-threatening and requires immediate medical attention.

Diagnosis

Diagnosis of angioedema is primarily clinical, based on the characteristic swelling and patient history. Laboratory tests may include:

• Measurement of C4 and C1 inhibitor levels for hereditary angioedema.
• Allergy testing for allergic angioedema.

Management

The management of angioedema depends on the underlying cause:

• Acute Management: Involves airway protection, administration of antihistamines, corticosteroids, and epinephrine for allergic angioedema.

• Long-term Management: For hereditary angioedema, prophylactic treatments such as C1 inhibitor concentrates, bradykinin receptor antagonists, or kallikrein inhibitors may be used.

Prognosis

The prognosis of angioedema varies depending on the type and severity. Allergic angioedema often resolves with treatment, while hereditary angioedema requires ongoing management to prevent attacks.

Also see

• Urticaria
• Anaphylaxis
• Bradykinin
• C1 inhibitor